mar vasto final article

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Pure and Applied Geophysicspageoph ISSN 0033-4553Volume 168Combined 3-4 Pure Appl. Geophys. (2010)168:543-582DOI 10.1007/s00024-010-0164-3

Hazard Evaluation in Valparaíso: theMAR VASTO Project

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Hazard Evaluation in Valparaıso: the MAR VASTO Project

MAURIZIO INDIRLI,1 HOBY RAZAFINDRAKOTO,2,3 FABIO ROMANELLI,4 CLAUDIO PUGLISI,1 LUCA LANZONI,5

ENRICO MILANI,6 MARCO MUNARI,7 and SOTERO APABLAZA8

Abstract—The Project ‘‘MAR VASTO’’ (Risk Management in

Valparaıso/Manejo de Riesgos en Valparaıso), funded by BID/

IADB (Banco InterAmericano de Desarrollo/InterAmerican

Development Bank), has been managed by ENEA, with an Italian/

Chilean joined partnership and the support of local institutions.

Valparaıso tells the never-ending story of a tight interaction

between society and environment and the city has been declared a

Patrimony of Humanity by UNESCO since 2003. The main goals

of the project have been to evaluate in the Valparaıso urban area

the impact of main hazards (earthquake, tsunami, fire, and land-

slide), defining scenarios and maps on a geo-referenced GIS

database. In particular, for earthquake hazard assessment the real-

istic modelling of ground motion is a very important base of

knowledge for the preparation of groundshaking scenarios which

serve as a valid and economic tool to be fruitfully used by civil

engineers, supplying a particularly powerful tool for the prevention

aspects of Civil Defense. When numerical modelling is success-

fully compared with records (as in the case of the Valparaıso, 1985

earthquake), the resulting synthetic seismograms permit the gen-

eration of groundshaking maps, based upon a set of possible

scenario earthquakes. Where no recordings are available for the

scenario event, synthetic signals can be used to estimate ground

motion without having to wait for a strong earthquake to occur

(pre-disaster microzonation). For the tsunami hazard, the available

reports, [e.g., SHOA (1999) Carta de Inundacion por Tsunami para

la bahia de Valparaıso, Chile, http://www.shoa.cl/servicios/

citsu/citsu.php], have been used as the reference documents for

the hazard assessment for the Valparaıso site. The deep and

detailed studies already carried out by SHOA have been

complemented with (a) sets of parametric studies of the tsunami-

genic potential of the 1985 and 1906 scenario earthquakes; and (b)

analytical modelling of tsunami waveforms for different scenarios,

in order to provide a complementary dataset to be used for the

tsunami hazard assessment at Valparaıso. In addition, other tar-

geted activities have been carried out, such as architectonic/urban

planning studies/vulnerability evaluation for a pilot building stock

in a historic area and a vulnerability analysis for three monumental

churches. In this paper, a general description of the work is given,

taking into account the in situ work that drove the suggestion of

guidelines for mitigation actions.

Key words: Hazard, vulnerability, risk, GIS, earthquake sce-

nario, tsunami.

1. Introduction

1.1. The Project ‘‘MAR VASTO’’ and its Partnership

‘‘MAR VASTO’’ (MAR VASTO, 2007; http://

www.marvasto.bologna.enea.it), funded by BID/

IADB (Banco InterAmericano de Desarrollo/Inter-

American Development Bank), has been coordinated

by ENEA (Italian Agency for New Technologies,

Energy and the Environment), with the participation

of several partners (Italy: Ferrara University,

Departments of Architecture and Engineering; Padua

University, Department of Structural and Transpor-

tation Engineering; Abdus Salam International Centre

for Theoretical Physics/Trieste University; Chile:

Technical University Federico Santa Maria of

Valparaıso, Civil Works Department; University of

Chile in Santiago, Division Structures Constructions

Geotechnics), and support of local stakeholders.

Valparaıso being included since 2003 in the UNE-

SCO Word Heritage List of protected sites, the

project’s main goals have been the following: to

collect and elaborate existing information and artic-

ulate a satisfactory evaluation of main hazards; to

1 ENEA (Italian National Agency for New Technologies,

Energy and Sustainable Economic Development), Bologna and

Rome, Italy.2 Laboratory of Seismology and Infrasound, Institute and

Observatory of Geophysics, Antananarivo, Madagascar.3 ICTP (The Abdus Salam International Centre for Theoret-

ical Physics), Trieste, Italy.4 Department of Geosciences, University of Trieste, Via

Weiss 4, 34127 Trieste, Italy. E-mail: [email protected] IUSS (University Institute for Higher Studies), University

of Ferrara, Ferrara, Italy.6 Department of Engineering, University of Ferrara, Ferrara,

Italy.7 Department of Structural and Transportation Engineering,

University of Padua, Padua, Italy.8 Board of Architects of Chile, Valparaıso, Chile.

Pure Appl. Geophys. 168 (2011), 543–582

� 2010 Springer Basel AG

DOI 10.1007/s00024-010-0164-3 Pure and Applied Geophysics

Author's personal copy

develop a geographic information system (GIS) dig-

ital archive that is user-friendly and easily

implemented, including hazard maps and scenarios;

to provide a vulnerability analysis for three historical

churches (La Matrız, San Francisco del Baron, Las

Hermanas de la Divina Providencia, made of various

materials—masonry, concrete, wood and adobe—and

located in different city sites) and for a building stock

in the Cerro Cordillera (partially inside the UNESCO

area); and to suggest guidelines for future urban

planning and strengthening interventions.

1.2. The Support of Local Institutions

During the work, many Chilean Organizations

cooperated with the Italian team: above all, the

Valparaıso Municipality, providing logistic and tech-

nical support; the Regional Authority (Intendencia V

Region Valparaıso); the Church (Archbishop of

Valparaıso and Franciscan Order of Friars Minors);

the Civil Defense (OREMI); the Chilean Navy

Hydrographic and Oceanographic Service (Servicio

Hidrografico y Oceanografico de la Armada de Chile,

SHOA); the PRDUV (Programa de Recuperacion y

Desarrollo Urbano de Valparaıso); the Firemen

(Bomberos) and the Sea Rescue (Bote Salvavidas)

Corps of Valparaıso; the Valparaıso Board of

Architects, several professionals and other universi-

ties; the Police (Carabineros de Chile); and the

Valparaıso Italian Community. Also important was

the contribution of Geocom Santiago, providing the

survey laser-scanner equipment. Moreover, qualified

professionals of the Valparaıso Municipality have

been provided short fellowships in Italy, funded by

the Italian Latin American Institute (IILA, Istituto

Italo Latino Americano).

2. The Project

2.1. A Brief Description of Valparaıso

The Valparaıso Bay was reached by the Spanish

conquerors in 1536, who first settled in the ancient

nucleus of the ‘‘Puerto’’, and then expanded into the

Almendral area (Fig. 1). The city represents a

distinctive case of growth, inside a remarkable

landscape, of an important Pacific Ocean seaport

(over the XIX-XX centuries). It achieved strategic

importance in shipping trade, but declined after the

Panama Canal opening (1914). Valparaıso tells the

never-ending story of a tight interaction between

society and environment, stratifying different urban

and architectonic layers, sometimes struck by disas-

ters and always in hazardous conditions.

Valparaıso’s morphology can be roughly divided

into two main sectors: a flat harbour area (growing on

lands reclaimed over centuries, see Fig. 2) and the

Figure 1Valparaıso: origin (left) and present situation (right)

544 M. Indirli et al. Pure Appl. Geophys.


hill quarters. Large neoclassic masonry buildings,

some previous colonial style constructions (some of

which are still standing, spared by earthquakes and

following fires) and more recent architecture occupy

the commercial district, with straight streets, high-

ways and rail tracks parallel to the coast. A wide area

is occupied by the port facilities up to the waterfront.

Otherwise, the steep forty-nine hills, cut by ravines

(quebradas) and climbed by narrow and snaky lanes,

are deeply populated by small and squat houses,

typically constructed of wooden frames, adobe panels

and covered by zinc tinplate (calamina). In addition

to these pervading clustered homes, notable historical

buildings are also present (Figs. 3, 4, 5, 6). In fact,

Valparaıso shows an irregular urban tissue and its

building inventory is very inhomogeneous. There-

fore, it is possible to say that Valparaıso is a city

‘‘with and without architects’’ (Fig. 7), in which the

work of anonymous citizens has accumulated,

together with the construction of remarkably

designed buildings, sometimes copies of European

ones but built with different materials.

Several old cable cars (ascensores) ascend the

slope (Fig. 8). The historic district (Barrio Puerto,

protected by UNESCO) lies in Southern Valparaıso

and embraces a sector which, starting from the flat,

reaches the hills (red line, Fig. 9). Furthermore, the

Valparaıso Municipality declared all the city lying

Figure 2Growth of Valparaıso on reclaimed lands

Figure 3Valparaıso: the flat area and the harbor

Vol. 168, (2011) Hazard Evaluation in Valparaıso 545


within the hills amphitheatre to be a protected area

(green line, Fig. 9). Certainly, the city is subjected to

various natural hazards (seismic events, but also

tsunamis, landslides, etc.) and anthropic calamities

(mainly wild and human-induced fires). These fea-

tures make Valparaıso a paradigmatic study of hazard

mitigation, and risk factors must be very well

evaluated during future restoration phases.

2.2. The Project Architecture

‘‘MAR VASTO’’ can be summarized as shown by

Fig. 10: horizontal lines give the ‘‘general purpose’’

activities, while targeted investigations are reported

in the two columns.

As it would be impossible to manage deep

investigations for the entire Valparaıso historic area

(due to limited resources in funds and time), a common

decision with Chilean partners and stakeholders has

been taken on structures/areas to be investigated, with

the highest priorities identified as:

– a building stock in the Cerro Cordillera (partially

included in the UNESCO zone);

– three important historical churches (‘‘La Matriz’’,

‘‘San Francisco del Baron’’, ‘‘Las Hermanas de la

Divina Providencia’’), made of different materials

and located in different city sites (Fig. 11).

3. The GIS Database

The first ‘‘general purpose’’ activity was the

organization of a Geographic Information System

Figure 4Valparaıso: buildings in the flat area

Figure 5Valparaıso: the hills quarters



(GIS) geo-referenced database encompassing all of

Valparaıso, building (at ENEA) a detailed Digital

Elevation Model (DEM) of the Valparaıso area

by generating ortho-photos from the very helpful

aerial photos provided by SHOA. Digital carto-

graphy (streets, buildings, quoted points, and other

Figure 6Valparaıso: buildings in the hills

Figure 7Valparaıso: a city ‘‘with and without architects’’

Figure 8Examples of Valparaıso cable cars



information) provided by the Valparaıso Municipal-

ity, often not very accurate, did not match the aerial

photos of the Valparaıso area. Therefore, a field

survey using Differential Global Positioning System

(DGPS) was been carried out in situ (a pattern of 33

points) in order to check aerial photos and

Figure 9Valparaıso: hazards and safeguarded areas

Figure 10Brief description of the ‘‘MAR VASTO’’ Project



cartography, verifying the GIS database from the

topographic point of view, removing uncertainties,

and clarifying unequivocally the real geographic

positions. The GIS platform organized in clear and

user-friendly maps a huge amount of data of general

interest, including aerial and satellite photos; car-

tography and topo-bathymetry; GIS urban layers such

as buildings, open spaces and viability; geo-refer-

enced historic maps, etc. (see examples in Fig. 12).

The GIS also includes information targeted on spe-

cific hazards and the building inventory of the Cerro

Cordillera pilot study sector (MAR VASTO, 2007;

INDIRLI, 2009).

All the details are in DGPS survey (2008) and

GIS database, (2008) (http://www.marvasto.bologna.

enea.it).

4. Hazard Maps

4.1. Introduction

Hazard maps have been developed for natural

(earthquake, tsunami, landslide) and anthropic (fire)

disasters and then stored in the GIS database (MAR

VASTO, 2007; INDIRLI, 2009). In this article more

attention is given to earthquake and tsunami hazards,

while the others are briefly described.

4.2. Seismic Hazard

4.2.1 General Information

Chile is one of the most earthquake-prone countries

in the world; it was struck by the most powerful

seismic event ever recorded (1960 Valdivia earth-

quake and tsunami). Valparaıso has been hit by other

major earthquakes (Table 1). In particular, the 1906

event was the most destructive; the damages (clas-

sified using 1906 pictures) were concentrated mostly

in the ‘‘El Almendral’’ neighborhood of the Valpa-

raıso harbor (Fig. 13a). Chilean partners have

provided microzonation studies (performed in order

to identify local soils effects), new evaluation of

earthquake intensities, isoseismal maps in the dam-

aged area. Three 1906 centennial undamaged

surviving buildings also survived 1985 Chile earth-

quake (see Fig. 13b; ASTROZA, 2007; SARAGONI, 2007;

STURM, 2008).

Specific studies on seismic hazard have been

carried out. It is worth noting that the neo-determin-

istic approach (PANZA et al., 2001) has been followed

Figure 11Location of the selected churches in Valparaıso



in the ‘‘MAR VASTO’’ Project, in order to evaluate

the seismic input in the Valparaıso area for certain

earthquake scenarios (in general), and in some

sections underneath the churches locations (in par-

ticular). A complete description of the methodology,

from the definition of the hazard to the seismic input

calculation for the design of a building, is given in

ZUCCOLO et al. (2008). Case studies indicate the limits

of probabilistic seismic hazard analysis (PSHA), the

currently used methodology, supplying indications

that it can be useful but not sufficiently reliable

(DECANINI et al., 2001; INDIRLI et al., 2006; KLUGEL

et al., 2006). Though deeply rooted in engineering

practice, PSHA has been called into question by

recent examples (the earthquakes of: Michoacan

1985, Kobe 1995, Bhuj 2001, Boumerdes 2003,

Bam 2003 and E-Sichuan 2008 events), that acted as

catalysts for the use of zoning in seismic risk

management. A drastic change is required in the

orientation of zoning, which must be a pre-disaster

activity performed to mitigate the effects of the next

earthquake using all available technologies. Seismic

zoning can use scientific data banks, integrated in an

expert system, by means of which it is possible not

only to identify the safest and most suitable areas for

urban development, but also to define the seismic

input that is going to affect a given building.

Figure 12Organization of the GIS database for Valparaıso

Table 1

Strong earthquakes striking Valparaıso (e.g. LOMNITZ, 1971; 1983)

Date Location M

Year Month Day

1647 05 13 Valparaıso, Chile 8.50




1965 03 28 La Ligua, North Valparaıso, Chile 7.10

1971 07 09 Valparaıso Region, Chile 7.50

1985 03 03 Offshore Valparaıso, Chile 7.80



Seismic hazard assessment, necessary to design

earthquake-resistant structures, can be performed in

various ways, following a probabilistic or a deter-

ministic approach. National seismic codes and

zonations are often based on seismic hazard assess-

ments computed with PSHA (CORNELL, 1968;

SSHAC, 1997; GSHAP; TANNER and SHEDLOCK,

2004). An example for Chile using the PSHA

approach is shown by Fig. 14.

Nevertheless, the PSHA cannot be sufficiently

reliable to completely characterize the seismic hazard,

because of the difficulty in defining the seismogenic

zones and in correctly evaluating the occurrence of

earthquakes (frequency–magnitude relations) and the

Figure 13The Valparaıso 1906 earthquake


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propagation of their effects (attenuation laws). A more

adequate description of the seismic ground motion can

be achieved following a neo-deterministic approach,

which allows for a realistic description of the seismic

ground motion due to an earthquake of given distance

and magnitude (PANZA et al., 2001). This approach,

which can be feasibly applied at urban scales, is based

on modelling techniques that have been developed

from the knowledge of the seismic source generation

and propagation processes. It is very useful because it

permits engineers to define a set of earthquake

scenarios and to compute the associated synthetic

signals, without having to wait for a strong event to

occur.

• Synthetic signals can be produced in a short time and

at a very low cost/benefit ratio, and can be used as

seismic input in subsequent engineering analysis

aimed at the computation of the seismic response of

structures. Modelling can be done at different levels

of detail, depending on the available knowledge of

geological, geophysical, seismological and seismo-

tectonical setting. The realistic modelling of the

ground motion is a very important base of knowl-

edge for the preparation of groundshaking scenarios

that represent a valid and economic tool to be

fruitfully used by civil engineers, supplying a

particularly powerful tool for the prevention aspects

of Civil Defense (pre-disaster microzonation).

Where the numerical modelling is successfully

compared with records (as in the case of the

Valparaıso 1985 earthquake), the synthetic seismo-

grams permit the generation of groundshakingmaps,

based upon a set of possible scenario earthquakes.

Concerning the seismic input, the major goal of

the ‘‘MAR VASTO’’ Project has been to provide a

dataset of synthetic time series representative of the

potential ground motion at the bedrock of Valparaıso,

especially at selected sites (e.g. the three important

churches located in the Valparaıso urban area: La

Matriz, San Francisco, Las Hermanas de la Divina

Providencia), for four scenarios, taking into account

two fault rupture typologies (unilateral and bilateral)

in the urban Valparaıso area, whose magnitudes are

reported in Table 2. The occurrence periods and risk

levels in Table 2 are intended solely for an engineer-

ing analysis and not in the sense of a return period

(for this purpose see e.g. COMTE et al., 1986).

The characteristics of the calculated signals (e.g.

amplitude, frequency content and duration of shaking)

are determined by the earthquake source process and

the wave propagation effects of the path between the

source and the site. The generation and selection of

realistic time series for design is essentially a problem

of choosing appropriately from among a number of

Figure 14Seismic hazard map (PGA in m/s2 with 10% probability of

exceedence in 50 years) of Chile using the probabilistic approach

(see http://www.seismo.ethz.ch/gshap/)

Table 2

Earthquakes scenarios for Valparaıso

M Occurrence period

7.5 Scenario

event

Occasional Tm & 120–

140 years

Strong

7.8 1985 event Sporadic Tm & 200–

250 years

Very strong

8.3 1906 event Rare Tm & 500 years Disastrous

8.5 Scenario

event

Exceptional Tm & 1,000 years Catastrophic


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future earthquake scenarios, whose most important

characteristics are their magnitude and the distance to

the site. From hazard maps, it is possible to define the

scenario earthquakes to be used in planning exercises

and earthquake engineering studies. Such an analysis is

accomplished by hazard deaggregation, in which the

contributions of individual earthquakes to the total

seismic hazard, their probability of occurrence and the

severity of the ground motions are ranked in the order.

Using the individual components (‘‘deaggregating’’

the events driving the hazard at the target region) of

these hazard maps, the user can properly select the

appropriate scenarios given their location, regional

extent, and specific planning requirements. Thus, the

definition of earthquake scenarios depends on many

factors (e.g. historical seismicity, seismotectonic stud-

ies, engineering considerations) and is not intended as

an earthquake prediction. That is, no one knows in

advancewhen or how large a future earthquakewill be,

but making assumptions about the size and location

of a hypothetical future earthquake, one can make

a reasonable prediction of the effects (e.g. ground-

shaking) for planning and preparedness purposes.

Intermediate-termmiddle-range earthquake prediction

is possible at different scales (PERESAN et al., 2005).

One of the most difficult tasks in earthquake

scenario modeling is the treatment of uncertainties,

since each of the key parameters has an uncertainty

and natural variability, which often are not quantified

explicitly. A possible way to handle this problem is to

vary the modeling parameters systematically. Actu-

ally, a severe underestimation of the hazard could

come by fixing a priori some source characteristics

and thus the parametric study should take into account

the effects of the various focal mechanism parameters

(i.e. strike, dip, rake, depth, etc.). The analysis of the

parametric studies will allow the researcher to gen-

erate advanced groundshaking scenarios for the

proper evaluation of the site-specific seismic hazard,

with a complementary check based on both probabi-

listic and empirical procedures. Once the gross

features of the seismic hazard are defined and the

parametric analyses have been performed, a more

detailed modelling of the ground motion can be

carried out for sites of specific interest. Such a detailed

analysis should take into account the source charac-

teristics, the path and the local geological and

geotechnical conditions. This neo-deterministic

modelling goes well beyond the conventional deter-

ministic approach taken in hazard analyses—in which

only a simple wave attenuation relation is invoked—

in that it includes full waveform modelling.

4.2.2 Seismic Hazard at Regional Scale

Neo-deterministic seismic zoning (PANZA et al., 1996;

PANZA et al., 2001) is one of the newest and most

advanced approaches; it has been applied success-

fully to many areas worldwide (e.g. PARVEZ et al.,

2003). It can be used as a starting point for the

development of an integrated approach that combines

the advantages of the probabilistic and deterministic

methods, thus minimizing their respective drawbacks.

This approach addresses some issues largely

neglected in PSHA, namely how crustal properties

affect attenuation: ground motion parameters are not

derived from overly simplified attenuation functions,

but rather from synthetic time histories. Starting from

the available information on the Earth’s structure,

seismic sources, and the level of seismicity of the

investigated area, it is possible to estimate peak

ground acceleration, velocity, and displacement

(PGA, PGV, and PGD) or any other parameter

relevant to seismic engineering, which can be

extracted from the computed theoretical signals. This

procedure allows us to obtain a realistic estimate of

the seismic hazard in those areas for which scarce (or

no) historical or instrumental information is available

and to perform the relevant parametric analyses.

Synthetic seismograms can be constructed to

model ground motion at sites of interest, using

knowledge of the physical process of earthquake

generation and wave propagation in realistic media.

The signals are efficiently generated by the modal

summation technique (PANZA and SUHADOLC, 1987;

PANZA et al., 2001), so it becomes possible to perform

detailed parametric analyses at reasonable costs. The

flowchart of the procedure is shown in Fig. 15. The

first problem to tackle in the definition of seismic

sources is the handling of seismicity data. Basically,

what is needed is an evenly spaced distribution of the

maximum magnitude over the territory, but the data

available from earthquake catalogues are widely

scattered. Furthermore, earthquake catalogues are



both incomplete and affected by errors, so a smoothed

distribution is preferable (PANZA et al., 2001).

Specific seismograms have been computed at the

nodes of a grid, with step of 0.2�, that covers the

region of the Central Chile territory. 107 events have

been selected from the dataset collected by the

Servicio Sismologico Universidad de Chile (http://

ssn.dgf.uchile.cl/home/terrem.html), that have been

considered as the most representative between the

destructive earthquakes occurred in Chile, from 1570

till present, with a magnitude greater than 7. Four

different seismogenic zones have been defined using

the information about the seismicity and tectonics of

the area. The seismicity is discretized into

0.2� 9 0.2� cells, assigning to each cell the maxi-

mum magnitude recorded within it; a smoothing

procedure is then applied to account for spatial

uncertainty and for source dimensions. Since the aim

of this step is the average regional definition of

seismic input, a double-couple point source was

chosen, with a focal mechanism consistent with the

regime of the pertinent seismogenic zone (PANZA

et al., 2001), as shown in Fig. 16.

To define the physical properties of the source-site

paths, the territory is characterized by a structural

model composed of flat, parallel anelastic layers that

represent the average lithosphere properties at a

regional scale. We have defined the regional bedrock

structural model (the elastic and anelastic parameters

of the uppermost layers are shown in Table 3)

starting from the model proposed by MENDOZA et al.

(1994) and the related references.

The seismograms have been computed for an

upper frequency content of 10 Hz and the point

sources were scaled for their dimensions (Size Scaled

Point Source) using the relatively simple spectral

scaling laws by GUSEV (1983). Such a simple source

model gives a reliable upper bound of the PGA and,

at the same time, permits a realistic estimate of the

PGD and PGV. In Figs. 17, 18, 19 and 20 only some

examples of the wide set of results are shown. Next,

we focused (deaggregating the hazard) on the two

most important earthquake scenarios for Valparaıso:

the 1985 and 1906 events, belonging to seismogenic

zone 4. These events were chosen not only because of

their large magnitude, but also because of the damage

that they generated in Valparaıso (Saragoni, 2006).

We used the simple model of source (SSPS) to define

the upper bound of PGA for the entire study region; it

turns out to be about 1.2 or 0.5 g (after deaggrega-

tion), in good agreement with the Intensities values

reported for the 1906 event (Saragoni, 2006; ASTRO-

ZA, et al., 2006). The use of microzonation,

considering more complex and realistic sources,

allowed us to better delimit the zones at an urban

scale where the largest PGA can be expected.

Therefore, our procedure consisted of: (a) expeditious

and low-cost determination of hazard using simple

and easily available information about seismic

sources and their surrounding medium (this section),

(b) more realistic modeling (next sections) focused on

items of special interest for which more expensive

procedures are necessary and fully justified by the

exposed value.

4.2.3 Extended Source Models

A further step towards realism, would be to consider

the rupture process at the source and the related

directivity effect (i.e. the dependence of the radiation

SITES ASSOCIATEDWITH EACH SOURCE

EXTRACTION OFSIGNIFICANT

GROUND MOTION PARAMETERS

TIME SERIESPARAMETERS

P-SVSYNTHETIC

SEISMOGRAMS

SHSYNTHETIC

SEISMOGRAMS

HORIZONTALCOMPONENTS

FOCALMECHANISMS

EARTHQUAKECATALOGUE

SEISMIC SOURCES

REGIONALPOLYGONS

VERTICALCOMPONENT

STRUCTURALMODELS

SEISMOGENICZONES

Figure 15Flow-chart of the neo-deterministic procedure for seismic hazard

assessment at regional scale (see Panza et al., 2001). The vertical

component is routinely not used



at a site on its azimuth with respect to the rupture

propagation direction). To this end, extended source

models have been considered, using the algorithm for

the simulation of the source radiation from a fault of

finite dimensions, named pulse-based wideband syn-

thesis (PULSYN), developed by GUSEV and PAVLOV

(2006). The seismic waves due to an extended source

are obtained by approximating it with a rectangular

plane surface, corresponding to the fault plane on

which the main rupture process is assumed to occur.

Effects of directivity and of the energy release on the

fault can be easily modeled, simulating the wide-band

radiation process from a finite earthquake source/

fault. To represent an extended source, PULSYN

uses the main features of the HASKELL (1964) model

and discretizes the rectangular fault plane with a

grid of point sub-sources. The arrival of the rupture

front at a subsource switches its slip. However,

unlike Haskell model, the spatial distribution of slip

and the rupture velocity are treated as a random

process and characterized in a stochastic manner. In

fact, the small-scale details of the rupture process,

connected to heterogeneities in the stress distribu-

tion, though, in general, too complicated to be

date mag strike dip rake Zone 1 16/10/1981 7.2 345 86 -93 Zone 2 28/03/1965 7.3 350 80 -100 Zone 3 06/07/1979 6.0 11 54 105 Zone 4 16/08/1906 8.2 3 15 117

Figure 16Seismogenic zones and their representative events

Table 3

Elastic and anelastic parameters of the uppermost layers of the bedrock structural model

Thickness

(km)

Density

(g/cm3)

P-wave velocities,

Vp (km/s)

S-wave velocities,

Vs (km/s)

P-waves quality

factor, Qp

S-waves quality

factor, Qs

1.0000 1.70 4.000000 2.310000 100.00 50.00

3.0000 2.00 4.750000 2.740000 200.00 100.00

4.0000 2.30 5.560000 3.210000 400.00 200.00

8.9000 2.50 6.070000 3.500000 500.00 250.00

5.5000 2.65 6.530000 3.770000 600.00 300.00

15.000 2.80 7.000000 4.040000 600.00 300.00

30.000 3.28 8.000000 4.500000 600.00 300.00



exactly characterized, generate high frequency

waves when reached by the rupture front. In this

way the code PULSYN generates a source (phase

and amplitude) spectrum, which is close in ampli-

tude to GUSEV’S (1983) empirical curves and

reproduces the directivity effects (see Fig. 21) as

in the theoretical Haskell model.

With this approach we can simulate the time

histories using (1) Extended Source (ES) and (2)

Space and Time Scaled Point Source (STSPS)

methods. In the ES case, the source is represented

as a grid of point subsources, and their seismic

moment rate functions are generated, considering

each of them as realizations (sample functions) of a

non-stationary random process. Specifying in a

realistic way the source length and width, as well as

the rupture velocity, one can obtain realistic source

time functions, valid in the far-field approximation.

Finally, to calculate the ground motion at a site,

Green functions are computed with the highly

efficient and accurate modal summation technique,

for each subsource–site pair, and then convolved with

the subsource time functions and, at last, summed

over all subsources. Furthermore, assuming a realistic

kinematic description of the rupture process, the

stochastic structure of the accelerograms can be

reproduced, including the general envelope shape and

peak factors. The extended seismic source model

allows us to generate a spectrum (amplitude and

phase) of the source time function that takes into

accounts both the rupture process and directivity

effects, also in the Near Source region. In the second

case (STSPS), we use a mixture of extended and

point sources. We sum up the source time functions

generated by the distributed (point) subsources in

order to obtain the equivalent single source, repre-

sentative of the entire space and time structure of the

extended source, and the related Green Function. In

this way it is possible to perform expeditious

parametric studies useful for engineering analysis

(ZUCCOLO et al., 2008) to investigate the dependence

of the ground motion (in the time and frequency

domain) on source parameters (geometry, energy

release, etc.).

Figure 17Horizontal PGD distribution and Period in seconds of its maximum



4.2.4 Parametric Tests

The synthetic signals database has been greatly

expanded by performing a parametric study of ground

motion, taking into account variations due to the

choice of focal mechanism parameters. Varying the

geometry of the seismic source, different ground

motions at the Valparaıso site have been studied in

order to consider maximum excitation in both

longitudinal (P-SV motion) and transverse (SH

motion) direction, and in order to consider (starting

from the Maximum Historical Earthquake) both the

Maximum Credible Earthquake and the Maximum

Design Earthquake.

Computations of synthetic seismograms (dis-

placements, velocities and accelerations for the

radial, transverse and vertical components) were

carried out with a cut-off frequency of 10 Hz. All

the focal mechanism parameters of the original

source models obtained from the seismic catalogues

were varied in order to find the source mechanism

which produces the maximum amplitudes of the

various ground motion components. The preliminary

parametric test was performed to estimate the

dependence of the radiation pattern on the orientation

of the fault plane. This analysis allows for limited

changes in the assumed strike-receiver angle (which

is uniquely determined by the strike of the fault and

the coordinates of the epicentre and the receiver) to

avoid the case when one of the three components of

motion corresponds to a minimum of radiation. The

conventions adopted are explained in Fig. 22.

Firstly, the hypothetical receiver was taken to be

at an epicentral distance of 100 km; two focal

mechanisms have been adopted as starting models:

the one proposed by CHOY and DEWEY (1988), with

strike of 360�, dip 35�, rake 105� and the result given

by the CMT Catalogue of Harvard (http://www.

globalcmt.org/).

Then, the hypothetical receiver was taken to be at

an epicentral distance of 60 km; one focal mecha-

nism has been adopted as starting model, given by the

CMT Catalogue of Harvard (http://www.globalcmt.

org/), but with depth 25 km.

Figure 18Horizontal PGV distribution and Period in seconds of its maximum



To simulate the 1906 event at Valparaıso, the

receiver was taken to be in the Valparaıso urban area,

at an epicentral distance of about 48 km. The results

of these parametric studies allowed us to fix some of

the focal mechanism parameters for the computation

of synthetic signals along detailed profiles for this

scenario earthquake: the same values of dip and rake

(respectively 15 and 105�) were adopted; but, for thestrike receiver, we used values of 230� and 300�,respectively, for the transverse and radial components

of motion, corresponding to the maximum ground

motion amplitude.

To simulate the 1985 event at Valparaıso, the

receiver was taken to be in the Valparaıso urban area,

at an epicentral distance of about 30 km. The results

of these parametric studies allowed us to fix some of

the focal mechanism parameters for the computation

of synthetic signals along detailed profiles for this

scenario earthquake.

Details of this procedure are given in Earthquake

hazard (2008) (http://www.marvasto.bologna.enea.it).

Quantitative validation of the neo-deterministic

results was made using the only available observed

signals in Valparaıso urban zone, i.e., the ones

recorded during the 1985 earthquake at the El

Almendral (ALMEN) and Universidad Santa Maria

(UTFSM) recording stations (SARAGONI, 2006). Fig-

ure 23 shows an example of extended source model,

with the geographical reference. Many investigators

have studied the source parameters of the Chilean

earthquake of March 3, 1985 (BERESNEV and ATKIN-

SON, 1997; SOMERVILLE et al., 1991); in this study, we

have chosen the one proposed by CHOY and DEWEY

(1988), with a strike of 360�, a dip 35�, a rake of 105�and the result given by the CMT Catalogue of

Harvard (http://www.globalcmt.org/).

4.2.5 Comparison between Computed Results

and Recorded Signals

Figure 24a shows the first ‘‘blind test’’ simulated

seismograms (respectively displacement, velocity and

acceleration) along the NS and EW components using

the extended source models embedded in the bedrock

structural model and calculated at the El Almendral

station. The signals recorded at such a station, located

Figure 19Horizontal PGA distribution and Period in seconds of its maximum


personal copy

on a sedimentary cover, are shown in Fig. 24b and

confirm that the extended source and bedrock models

allow us to reproduce the observed amplitude and

duration of the ground motion. The comparison

between the simulated and the recorded signals and

the related response spectra at the UTFSM station

(located on bedrock) are shown in Fig. 25, and

demonstrate excellent agreement. Table 4 summarizes

the results of this ‘‘blind test’’, i.e., without any tuning

process or validation procedure, confirming that the

extended source and bedrock models are successfully

validated for the computation of the seismic input. Of

course, the visible differences reported in Table 4

between the observed and simulated maximum values

of the ground motion (i.e. acceleration, velocity and

displacement) would be reduced with a more targeted

inversion procedure.

4.2.6 Seismic Input at Urban Scale

The methodology explained above allowed us to

generate a set of groundshaking scenarios at bedrock

in the urban area of Valparaıso associated to different

‘‘scenario’’ earthquakes. The scenario earthquakes

can be classified, according to their different: (a)

magnitude, (b) occurrence period, Tm, and (c) risk

level (see Table 2). These are intended solely for an

engineering analysis and not in the sense of a return

period (for this purpose see e.g. COMTE et al., 1986).

For every scenario two rupture styles (unilateral

North to South and bilateral) have been considered and

the synthetic signals (displacements, velocities and

accelerations) for the two horizontal components of

motion (N–S and E–W) have been computed at a dense

grid (step of approximately 0.02 km) of sites in the

Valparaıso urban area. The peaks of the groundmotion

and their period of occurrence, have been extracted in a

matrix form; these results have been GIS processed

and graphically rendered in a set of 96 maps. The

results (see an example in Fig. 26) are extremely

important, since the information they carry can be

mapped in terms of intensity scenarios, allowing

comparison with the available measured intensities

for the 1985 and 1906 scenarios. PANZA et al. (1997)

Figure 20Horizontal PGA distribution and Period in seconds of its maximum after deaggregation



have produced new relations between Intensity I and

the peak values of acceleration, velocity and displace-

ment, valid for the Italian territory (see Table 5). They

used two different versions of the GNDT earthquake

catalogue (NT3.1 and NT4.1.1) and two sets of

observed intensity maps for the Italian territory (ING

and ISG data) and exploited advanced modelling

methods for seismic wave propagation (PANZA et al.,

2001). The results obtained for accelerations do not

differ significantly from the earlier results of CANCANI

(1904). From Tables 5, 6 and 7, it is evident that the

generated groundshaking scenarios at bedrock match

very well with the average intensities measured in

Valparaıso for the 1985 (VIII MSK) and the 1906 (IX

MSK) events as reported by SARAGONI (2006) and

Astroza et al. (2006).

Figure 21a Unilateral and bilateral rupture processes, b directivity effect and c an example of source spectra for a unilateral rupture at three different

sites, in the case of forward (red), neutral (green) and reverse (blue)


personal copy

4.2.7 Seismic Input along Selected Profiles: Site

Response Estimation

Coordinates of three sites collected during the in situ

DGPS campaign, see DGPS survey, 2008 were

selected as strategic targets for the whole project.

These were the locations of the three churches: La

Matriz, San Francisco and Las Hermanitas de la

Providencia (see Fig. 11) The full seismic input

(acceleration time histories and related response

spectra) at the bedrock was specifically computed

for these three locations. As an example (Fig. 27) the

time histories computed for the 1906 scenario (uni-

lateral rupture) at the La Matriz church are shown; it is

the only one located (see Fig. 28) on a bedrock site,

while the other two churches are located near the El

Almendral area characterized by the presence of a

sedimentary basin. Thus, the computation of the

seismic input at these sites can be affected by local

soil amplifications (as discussed later).

To deal both with realistic source and structural

models, including topographical features, a hybrid

method has been developed that combines modal

summation and the finite difference technique (FAH

and PANZA, 1994), and optimizes the use of the

advantages of both methods. Wave propagation is

treated by means of the modal summation technique

from the source to the vicinity of the local, hetero-

geneous structure that we want to model in detail. A

laterally homogeneous anelastic structural model is

adopted which represents the average crustal proper-

ties of the region. The generated wavefield is then

introduced into the grid that defines the heteroge-

neous area and is propagated according to the finite

differences scheme. With this approach, source, path

and site effects are all taken into account, and it is

therefore possible to conduct a detailed study of the

wavefield that propagates even at large distances

from the epicentre. This methodology has been

successfully applied to many urban areas worlwide

Figure 22Seismic source parameters and conventions adopted



(PANZA et al., 1999; ZUCCOLO et al., 2008), and to

strategic buildings and lifelines (ROMANELLI et al.,

2003, 2004; VACCARI et al., 2005).

In the hybrid scheme (see Fig. 29), two local

heterogeneous models have been coupled with the

average regional model used in the initial analysis for

the detailed modelling of earthquake ground motion

by computing synthetic seismograms in laterally

heterogeneous media. The two profiles, eachabout

2 km long and 0.2–0.4 km deep, have been selected

according to the available information and to their

representativeness of the most important areas of the

municipality (see Fig. 28). To define the sub-surface

topography of the sedimentary layers, we used

(VERDUGO, 1995, 2006a, b) the information given by

ESPINOZA (2000), elaborated for the bedrock model.

We then performed some parametric tests, i.e. (a)

including (or not) some very superficial layers, (b)

changing the values of elastic and anelastic param-

eters, (c) choosing different bedrock models and (d)

adopting the different scenarios previously defined.

In the following we show the results related to the

two profile models shown in Fig. 30, together with

the values of the adopted elastic and anelastic

parameters. The minimum S-wave velocity present

in the models shown is 660 m/s, and the mesh used

for the finite differences is defined with a grid spacing

of 7 m. This allows us to carry out the computations

at frequencies as high as about 10 Hz The synthetic

time signals (displacements, velocities and accelera-

tions) have been calculated for the three components

of motion, adopting a STSPS seismic source model

for the 1985 earthquake scenario.

Site effects are then evaluated as spectral ampli-

fications, described by the ratios (2D/1D) of the

acceleration response spectra, with 5% damping,

computed along the bedrock model (1D) profile and

along the one containing the local model (2D).

The amplification factors computed for the hor-

izontal components (up to 4) explain very well the

pattern of the measured intensities in the Valparaıso

urban area associated to the 1985 and the 1906

events, as reported for example by SARAGONI (2006)

and ASTROZA et al. (2006). In fact, a general result of

our investigation is that the local effects due to the

thickening of the sedimentary basin (up to 300 m) in

the El Almendral zone can cause an increment greater

than 1 unit in the seismic intensity experienced with

respect to the average intensity affecting the urban

area as a whole (see Fig. 13).

More details are given in Earthquake hazard

(2008) (http://www.marvasto.bologna.enea.it).

4.3. Tsunami Hazard

4.3.1 General Information

A tsunami occurs after a huge mass of water is

displaced by some force from its equilibrium config-

uration. Gravity acts as a restoring force, tending to

bring the displaced mass of water back to its original

equilibrium state. Most tsunamis are generated by

submarine earthquakes, but possible sources are also

inland/coastal earthquakes, landslides and meteoric

impacts. Due to their generation mechanism, periods

and wavelengths associated with tsunamis are longer

than those associated with ordinary wind-driven sea

waves; for large submarine earthquakes their ampli-

tudes can be very impressive, especially when the

waves approach the shorelines.

Figure 23Source and station geometry for the 1985 Valparaıso, Chile,

earthquake: map view showing horizontal projection of fault;

numbers in fault elements represent slip in meters (modified from

Somerville et al., 1991)



Figure 24El Almendral station: horizontal (N50E) component of acceleration, velocity and displacement for the 1985 event: a computed; b recorded

(thanks to R. Saragoni and S. Ruiz)



The Chilean coast is currently exposed to the

effects of tsunamis generated in the Pacific Ocean

(GUTIERREZ, 2005), and Valparaıso has been inun-

dated several times in the past. For instance,

catastrophic events of the nineteenth century, 1868

and 1877, overwhelmed the coast of the northern

region of the country. During the twentieth century,

the most important disaster was the 1960 earthquake

and tsunami in Valdivia, in the south of the country.

This event had a great impact on the coasts of most of

the neighbouring countries in the Pacific Ocean,

primarily in the Hawaiian Islands and Japan. The last

important event recorded along the Chilean coast was

the ‘‘good tsunami’’ which occurred in Antofagasta,

Figure 251985 event at UTFSM station: a Horizontal recorded accelerations; b simulated accelerations; c comparison of response spectra: this study,

recorded, and the one simulated by SOMERVILLE et al., 1991

Table 4

Peak ground motion values for (blind) simulated and observed signals

Receivers Components CHOY CMT OBS

Amax (g) Vmax (cm/s) Dmax (cm) Amax (g) Vmax (cm/s) Dmax (cm) Amax (g) Vmax (cm/s) Dmax (cm)

ALMEN N50�E 0.1516 23.05 9.16 0.128 12.07 6.22 0.2907 28.59 5.37

S40�E 0.1640 14.07 6.10 0.122 15.23 5.32 0.1621 16.89 2.81

UTFSM N70�E 0.1467 20.49 7.55 0.112 11.38 5.79 0.1767 14.70 3.26

S20�E 0.1399 14.07 4.54 0.139 18.94 5.68 0.1625 6.40 1.33

CHOY CHOY and DEWEY (1988), CMT centroid moment tensor, http://www.globalcmt.org/, OBS Observed



1995. This historic situation has contributed to an

awareness of the risk involved, and therefore to the

development of research on the subject in Chile. The

organization in charge of detecting and issuing the

warning is the Hydrographic and Oceanographic

Service of the Chilean Navy (SHOA; http://www.

shoa.cl). The tsunami warning head office is located

in the Department of Oceanography of SHOA. In the

last few years, new developments in technology have

made it possible to improve the quality of information

used in assessing the potential risk of a tsunami event

off theChilean coast. Since 1995, a TREMORSSystem

has been operating in Chile. This is system comprises

seismic monitoring equipment that improves the

existing seismic network and tsunami warning system

in Chile, giving information in real time of seismic

parameters and their relationship with some of the

parameters of tsunami generation in order to estimate

risk. A good example of the application and utility of

the technology was the tsunami warning issued by

SHOA for the 1996 Chimbote earthquake in Peru.

Figure 26Groundshaking scenario at the bedrock level in the Valparaıso urban area for the 1985 event. NS component of velocities for bilateral rupture

Table 5

ING–NT4.1.1 (MCS) (horizontal components)

Intensity Displacement (cm) Velocity (cm/s) DGA (g)

V 0.1–0.5 0.5–1.0 0.005–0.01

VI 0.5–1.0 1.0–2.0 0.01–0.02

VII 1.0–2.0 2.0–4.0 0.02–0.04

VIII 2.0–3.5 4.0–8.0 0.04–0.08

IX 3.5–7.0 8.0–15.0 0.08–0.15

X 7.0–15.0 15.0–30.0 0.15–0.30

XI 15.0–30.0 30.0–60.0 0.30–0.60

DGA design ground acceleration

Table 6

ISG–NT4.1.1 (MCS) (horizontal components)

Intensity Displacement (cm) Velocity (cm/s) DGA (g)

VI 1.0–1.5 1.0–2.0 0.01–0.025

VII 1.5–3.0 2.0–5.0 0.025–0.05

VIII 3.0–6.0 5.0–11.0 0.05–0.1

IX 6.0–13.0 11.0–25.0 0.1–0.2

X 13.0–26.0 25.0–56.0 0.2–0.4

DGA design ground acceleration



As a very important complement to the operative

work, SHOA has been working actively in the process-

ingof inundationmapsby tsunamis for theChilean coast

using the TIME project technology. Since 1996, after

theTIME training course inChile, theNationalTsunami

Warning System has been producing inundation charts

of the main ports to help the Civil and Maritime

Authorities to plan for and mitigate the effects of a

tsunami. During the period 1997–2004, twenty-eight

charts were produced under the project ‘‘Processing of

Inundation Maps by Tsunamis for the Chilean Coast’’.

The cities included in these charts (http://www.

shoa.cl/servicios/citsu/citsu.php) are: Arica, Iquique,

Tocopilla, Mejillones, Antofagasta, Taltal, Caldera,

Chanaral, Huasco, Coquimbo, La Serena, Los Vilos,

Papudo, Quintero, Valparaıso, Vina del Mar, Algar-

robo, San Antonio, Constitucion, Talcahuano, Penco,

Lirquen, Tome, San Vicente, Coronel, Lebu, Corral y

Ancud. Inundation maps have being used for tsunami

hazard planning by the national civil protection

agency (ONEMI) and other government institutions.

The SHOA report (SHOA, 1999), discussed by

the Italian team at the SHOA headquarters during the

in situ visit, should be used as the reference document

for the tsunami hazard assessment for the Valparaıso

site. The objective of this work is to complement the

deep and detailed studies already carried out by

SHOA, with (a) sets of parametric studies about the

tsunamigenic potential of the 1985 and 1906 scenario

earthquakes; (b) analytical modelling of tsunami

waveforms for different scenarios, in order to provide

a complementary dataset to be used for the tsunami

hazard assessment at Valparaıso.

4.3.2 Tsunami Simulation: Theory and Modelling

The traditional approach to model tsunami genera-

tion is based on solving hydrodynamic equations

Table 7

Comparison of seismic intensity scales

MM RF JMA MCS MSK

I I

II I

I II III II

II

III VI III III

IV IV

II V IV V

V IV III VVI

IV IIV VI IVVII

VII VIII

V

VIII VII IX

IIIV IIIV

IX X

IX VI

IX XI

X

X

X XII

XI VII

XI

IIX IIX

Adapted from Dolce et al. (2005)

MM Modified Mercalli, RF Rossi-Forel, JMA Japanese Meteorological Agency, MCS Mercalli–Cancani–Sieberg, MSK Medvedev–Spon-

heuer–Karnik



with boundary conditions at the ocean floor corre-

sponding to a static displacement caused by the

earthquake source (HAMMACK, 1973; LEE and CHANG,

1980; OKAL, 1982; COMER, 1984a, b). Another well-

developed approach is based on the modal theory

(POD’YAPOLSKY, 1968; WARD, 1980; COMER, 1984a,

b; PANZA et al., 2000). The former approach assumes

the ocean and solid Earth to be partially coupled,

whereas according to the latter they are fully

coupled. Though the modal theory gives a solution

corresponding to the exact boundary conditions, and

it may be easily extended to models with slightly

varying thickness of the water layer, it can be

applied only when a source is located under the

ocean. However, there are indications that sources

near a coastline, and even inland, may cause intense

tsunami waves. For the analysis of such a case a

suitable approach may be that based on the Green’s

function technique, as proposed firstly by KAJIURA

(1963) for the analysis of tsunamis excited by an

impulsive source.

4.3.3 Modal Summation Technique: Tsunamis

Generated by Offshore Earthquakes

The approach we use here for modelling tsunamis

generated by offshore earthquakes is an extension

(PANZA et al., 2000) to the case of tsunami propaga-

tion, of the well-known modal theory (POD’YAPOLSKY,

1968; WARD, 1980; COMER, 1984a, b) and therefore

we simply refer to it as ‘‘modal method’’. In this

approach it is assumed that the ocean and the solid

Earth are fully coupled. From the mathematical point

of view, in the modal approach the equations of

motion are solved for a multi-layered model structure

(according to HASKELL, 1964), so the set of equations

is converted into a matrix problem in which to look

for eigenvalues and eigenfunctions. In general, the

modal theory gives a solution corresponding to the

exact boundary conditions, and so it is easily

extended to models with slightly varying thickness

of the water layer. Therefore, the modal method

allows us to calculate synthetic signals for both

Figure 27Example of seismic input computed at the La Matriz church: 1906 scenario, unilateral rupture. Displacements, velocities and accelerations for

the two horizontal (North–South, NS, and East–West, EW) components of motion



Figure 28Bedrock model (depth) at El Almendral (VERDUGO, 1995; SARAGONI, 2006) and the position of the two profiles

Reference layered model

Zone of high attenuation, whereQ is decreasing toward theartificial boundary.

Artificial boundaries, limitingthe FD grid.

Adjacent grid lines, where the wavefield is introduced into the FD grid. Theincoming wave field is computed withthe mode summation technique. Thetwo grid lines are transparent forbackscattered waves (Alterman andKaral, 1968).

Site

SourceA

Distance from the source

A

Dep

th

Local heterogeneous model

Free surface

Figure 29Scheme of the hybrid (modal summation plus finite differences scheme) method (e.g. PANZA et al., 2001)



laterally homogeneous (1D) and laterally heteroge-

neous (2D) structures. For the 2D case, the structural

model is parameterized by a number of 1D structures

arranged in series along the profile from the source to

the receiving site. The liquid layer is considered to

be homogeneous and incompressible, no vertical

stratification of the water is considered. The param-

eterization of the bathymetry is important for the

longer source-site paths, since it can strongly influ-

ence travel times. In our calculations the number of

model structures varies from 2 to 14, depending

mainly on the number of slope-trending variations

along each path. It is a useful rule to keep the

parameterization as simple as possible. The modal

method has a major limitation: due to its intrinsic

mathematical formulation, it can be applied only

when a source is located under the ocean (i.e. is

applicable only to the offshore source case).

4.3.4 Green’s Function Approach: Tsunamis

Generated by Inland/Coastal Earthquakes

There are several indications that sources near, or

even inside, a coastline may cause intense tsunami

waves. For the analysis of such cases, a suitable

approach to compute synthetic mareograms has been

developed by Yanovskaya et al. (2003) with the

Green’s function technique, which solves the prob-

lem of modelling tsunamis generated by inland/

coastal sources. This method uses the representation

theorem together with the Green’s function as first

proposed by KAJIURA (1963) for the calculation of

tsunamis generated by an extended source under an

infinite water layer of constant thickness. This case is

then extended with the addition of a coastline,

considering a semi-infinite water layer of constant

thickness. The exact solution for the Green’s function

in the liquid layer is represented in an integral form,

and therefore, to solve the problem, it is necessary to

adopt an approximation. The approximation adopted

is the well-known asymptotic representation of the

integral solution by Hankel’s functions, which allows

calculation only for the far-field case.

A rough evaluation, in the case of tsunamis in a

shallow water domain, fixes the lower limit for

source-site distances that can be considered in this

approximation at about ten kilometers.

4.3.5 Wave Propagation

Since we use two-dimensional and one-dimensional

models, we can compute mareograms only along

Figure 30Local profiles (top: red line of Fig. 28; bottom: blue line of Fig. 28) with their elastic and anelastic parameters



straight segments from the source to the receiver

sites, neglecting all three-dimensional effects, such as

refraction and diffraction; this is a limitation of our

method. When analyzing the results one has to take

into consideration that variations of the sea depth can

cause refraction and thus focusing or de-focusing of

the wave in some regions. Diffraction of the wave

front may also play a significant role in the presence

of obstacles such as an island or a peninsula.

Moreover, a number of local effects can generally

occur in proximity to the coast due to the thinning of

the liquid layer, strongly influencing both travel time

and maximum amplitude. The ensamble of this

phenomena is often called shoaling and is responsible

for the final tsunami run-up. The major contribution

is the amplification of the wave approaching the coast

due to the progressive thinning of the water layer.

The principle of conservation of energy requires that

the wave energy, when the tsunami reaches shallow

waters, is redistributed into a smaller volume, which

results in a growth of the maximum amplitude.For the

shoaling amplification factor linear theory gives a

simple expression, known as Green’s law. Typically

the shoaling factor ranges from 1 (no growth) up to

several units (amplification) depending on the con-

sidered domain (WARD, 2002). Shoaling amplification

acts until the wave amplitude is approximately less

than half the sea depth (WARD and DAY, 2008), then

nonlinear phenomena cause the waves to break and

eventually turn them backward. WARD and DAY

(2008) suggest that due to complications of wave

refraction and interference, runup is best considered

as a random process that can be characterized by its

statistical properties. Models and observations hint

that runup statistics follow a single skewed distribu-

tion spreading between 1/2 and 2 times its mean

value. Another phenomenon contributing to the wave

amplification is the overlapping of the signal, due to

the fact that waves travel more slowly in shallow than

in deep waters, so the front of the wave packet that

first reaches shallow waters, is overtaken by the tail

of the signal. This often results in a growth of the

maximum amplitude.

When dealing with very long source-site distances

(hundreds of kilometers), an additional effect on

tsunami maximum amplitude becomes relevant due

to the phenomenon of dispersion, i.e., the fact that the

components at low frequency of the signal travel

faster than the higher ones. After a certain distance

the slower high-frequency components tend to

migrate to the tail of the wavetrain where they no

longer contribute to the main peak amplitude.

4.3.6 Hazard Scenarios

The main purpose in modelling a hazard scenario is

to assess the maximum threat expected from a studied

phenomenon in a certain area and to give specific

directives to the local authorities in order to prevent

and mitigate serious consequences on the population,

the infrastructures and the environment. By means of

modelling, we have calculated the maximum ampli-

tude of the vertical displacement of the water

particles on the sea surface and the travel time of

the maximum amplitude peak, since they are the most

relevant aspects of the tsunami wave and also are the

only characteristics always recorded in the chronicles

and therefore in catalogues. The horizontal displace-

ment field has been calculated, too, and, in average, it

exceeds the vertical one by approximately an order of

magnitude (this accounts for the great inundating

power of tsunami waves with respect to wind-driven

waves). To calculate tsunami hazard scenarios

(see Table 8) we have first adopted the scenario

events (1985 and 1906) and the source model

described by SHOA (SHOA, 1999) and then we

proceeded to model the tsunami for other possible

scenarios.

It is important to mention that the extremely

efficient analytical modelling techniques (computa-

tion times are of the order of seconds and are bound

to decrease with the natural rate of improvement of

computers) for real time simulations can be utilized

also for a Tsunami Warning System, since they can

be compared with real time incoming open-sea level

data, in order to validate, or close, an impending

alarm.

4.3.7 Parametric Studies

The quick, accurate and efficient analytical model-

ling techniques are used to generate a preliminary

dataset of synthetic mareograms, performing para-

metric studies to define the influence of the focal



mechanism (strike, dip, rake and focal depth) on

the tsunamigenic potential of the seismic sources

associated to the scenario events. In particular, the

modal technique is used for the most significant

tsunami events with source located offshore (whose

hypocentre is located under the sea bottom).

Varying the geometry of the seismic source,

different tsunamis at the Valparaıso site have been

studied, in order to consider the maximum tsunami-

genic excitation and in order to consider (starting

from the Maximum Historical Earthquake) both the

Maximum Credible Earthquake and the Maximum

Design Earthquake. All the focal mechanism param-

eters of the original source models obtained from the

seismic catalogues were varied in order to find the

source mechanism producing the maximum ampli-

tude of the tsunami. A preliminary parametric test

was performed to estimate the dependence of the

radiation pattern on the orientation of the fault plane

(see Fig. 22 for the convention adopted in the focal

mechanism parameters). The starting source model is

the one proposed by SHOA for the 1985 and 1906

Valparaıso earthquakes (SHOA, 1999), as shown in

Table 9.

The calculations were performed using the 1985

scenario as the reference event and a laterally

homogeneous oceanic model with a water layer of

1.5 km. The value of 1.5 km for the thickness of the

oceanic layer represents the average bathimetric

depth from the source area to the Valparaıso site,

taken to be at a distance of about 50 km. This simple

model gives a reliable upper bound of the height of

the tsunami (about 3 meters) and the signal computed

with this configuration represents the ‘‘reference’’

signal for the other simulations.

Details are given in Tsunami hazard (2008)

(http://www.marvasto.bologna.enea.it).

4.3.8 Laterally Heterogeneous Oceanic Models

With the modal approach it is very easy to perform

expeditious computations for laterally heterogeneous

oceanic models (PANZA et al., 2000; PAULATTO et al.,

2007) and we computed the tsunami signals at the

Valparaıso site for different cases; the results are

shown in Fig. 31. In such a 2D case, the structural

model is parameterized by a number of 1D structures

arranged in series along the profile from the source to

the receiving site.

Details are given in Tsunami hazard (2008)

(http://www.marvasto.bologna.enea.it).

4.3.9 Extended Sources

For source-site distances comparable with the dimen-

sion of the source (near-source), the space extension

of the fault may be relevant. In that case the point

source approximation may be too crude for the

Table 8

Tsunami scenarios for Valparaıso

M Occurrence period

7.0 Scenario event Frequent Tm & 70–80 years Moderate/strong

7.5 Scenario event Occasional Tm & 120–140 years Strong

7.8 1985 event Sporadic* Tm & 200–250 years Very strong

8.3 1906 event Rare* Tm & 500 years Disastrous

8.5 Scenario event Exceptional Tm & 1,000 years Catastrophic

* From SHOA source models and simulations

Table 9

Fault parameters for the simulation of the 1906 and 1905 Tsunamis

(SHOA, 1999)

Parameters Tsunami 1906 Tsunami 1985

South extreme 35.1�Lat.S-72� Lon.W 34.38�Lat.S-72� Lon.WSlip 4.6 m 2.8 m

Length 330 km 200 km

Width 130 km 90 km

Strike N10�E N10�EDip 18� 18�Depth 15 km 17 km

Rake 90� 105�



estimation of arrival times, so we adopted an

extended source model (see also Earthquake Hazard

2008). To obtain mareograms for the extended source

we have developed FORTRAN code that uses the

data of the slip distribution along the fault obtained

by stochastic procedures using another program

(PULSYN) developed by A. Gusev (GUSEV and

PAVLOV, 2006). This last program discretizes the

fault and assigns a value of the slip and of rupture

time to each subsource (see Fig. 32). The character-

istic of each subsource is then used as an independent

source to model the tsunami and the sum of all the

signals obtained gives us a final mareogram for the

extended source.

Using this approach, the tsunami time series have

been computed, with a laterally homogenous model,

at the Valparaıso site for different magnitudes which

can be associated with different earthquake scenarios.

The results are shown in Fig. 33.

Summarizing the work, using as a base of

knowledge the inundation map provided by SHOA

(SHOA, 1999; see Fig. 34) associated to the 1906

event, an upper bound of the multiplication factor

for the tsunami hazard to be used for the different

Figure 31Tsunami signals computed for the reference case (1D) and different laterally heterogeneous models (2D)

Figure 32An example of 2D final slip function and rupture history on the fault plane, obtained with Pulsyn (GUSEV and PAVLOV, 2006)



scenarios can be read in Fig. 35. The figure shows

the tsunami heights, computed with a scaled and

an extended source, are plotted versus magnitude

and the associated amplifications (using as refer-

ence the 1906 level, whose effective measured

height is debatable since the reports are

contradictory).

From the results it emerges that the coastal line in

the Valparaıso harbour zone could be considered

exposed to a relatively high risk of flooding.

Figure 33Tsunami signals computed at the Valparaıso site (about 50 km) for different magnitudes (from 7.5 to 8.7) considering extended source models

Figure 34SHOA tsunami inundation map



4.4. Landslide Hazard

Thanks to the indispensable support of SHOA,

Valparaıso Municipality and local universities, slope,

landslide inventory and susceptibility maps (Fig. 36)

have been provided through in-field campaign (in

particular in the pilot sector of the Cerro Cordillera),

reconstruction of past landslide events from historic

archives, pluviometric analysis and digital/analogical

aerial photos elaboration. Landslide hazard is very

high in the entire Valparaıso amphitheatre. The

upstream hillside is characterized mainly by mud-

debris flow events, triggering a couple of times in the

year, concentrated in the summer season. The intensity

of those phenomena can vary widely, but the presence

of densely populated urban settlements in ravine beds,

escarpment sides and valley heads (often artificially

terraced) makes the associated risk very high. The

coastal flat is reached by moved materials only when

the event is intense or when several activated areas

merge and flow together in the same bed. Fall events

are punctual and characterized by local effects, but

often destructive, at the basis of the sub-vertical

sides. Certainly, seismic ground shaking as starting

point of landslide phenomena should be carefully

investigated.

The complete study is available in Landslide

hazard (2008) (http://www.marvasto.bologna.enea.it).

4.5. Fire Hazard

Fires certainly are the most frequent and danger-

ous Valparaıso disasters. The ‘‘state-of-the-art’’

information has been provided by Firemen Corp

and Valparaıso Municipality, with particular regard

Figure 35a Maximum height and b amplification compared to the reference event (1906 earthquake) for the scenario earthquakes considered

Figure 36Landslide susceptibility maps



to the Calle Serrano tragedy. In fact, on February 3rd,

2007, a violent explosion due to a gas leak killed four

people, destroyed some heritage buildings and dam-

aged others in Calle Serrano, in the core of the

UNESCO zone. Despite the expertise of local

firemen, fires occur in the urban area (due to bad

maintenance of electric systems and gas pipelines,

building materials, lack of education and vandalism),

but also in the surroundings forests and bushes

(mainly human-made events). The risk is worsened

by usual windy weather, narrow and tortuous hill

roads, presence of wooden houses and sometimes

insufficient water pressure in the hydrants. The

presence of the close harbor facilities represents a

further risk factor. Moreover, important monuments

were burned during the 1906 earthquake, but also

damaged by recent fires (as the Church of ‘‘San

Francisco del Baron’’ in 1983). Figure 37 shows the

hazard map, marking the most fire-prone Valparaıso

locations. The work has been verified by a couple of

recent fire events: they occurred exactly in one of the

areas identified as most fire-prone in the GIS

database.

The complete study is available in Fire hazard

(2008) (http://www.marvasto.bologna.enea.it).

5. The Cerro Cordillera Investigation

Geo-referred hazard maps must interact with a

detailed land and building inventory, in which urban

planning and single construction features (architec-

ture, structural characteristics, vulnerability, present

status, etc.) are linked to the surrounding environ-

mental and social context. The pilot zone of the Cerro

Cordillera is an historically ‘‘virgin’’, socially com-

plicated and poor sector, partially inside the

UNESCO area, delimited by Calle Serrano (plane

side), the San Agustin cable car upper station (hill

side), and by the two opposite ravines of San Fran-

cisco and San Agustin (Fig. 38).

The architectonic/urban planning investigation

encompassed 230 buildings, 4 public areas and about

50 road network stretches. The information (function,

architectonic style, general condition, etc., see

Fig. 38a1–a3) has been picked up through in situ

Figure 37Fire hazard map for Valparaıso



surveys (by using an investigation form specifically

designed for Valparaıso), and then stored in the GIS.

Different indexes properly overlapped (for example,

high architectonic quality and bad conditions,

Fig. 38a4), enabled us to identify rehabilitation

priorities.

On the basis of the above work, earthquake vul-

nerability investigation incorporated 70 structures

(Fig. 39), when exhaustive cadastral data were

available (plans, prospects, sections, construction

details, geotechnical features, etc.), excluding infor-

mal and illegal houses.

A special form was elaborated for Valparaıso,

modeled upon established Italian procedures

(GNDT, 1999). Almost one half of the analyzed

units shows a high vulnerability index IV (22%

0\ IV\ 30 low vulnerability; 20% 30\ IV\ 45

average vulnerability; 16% 45\ IV\ 60 high

Figure 38Investigation in the Cerro Cordillera: architectonic/urban planning analysis

Figure 39Investigation in the Cerro Cordillera: vulnerability analysis


personal copy

vulnerability; 42% 60\ IV\ 100 very high

vulnerability).

The complete study is available in Cerro Cordil-

lera (2008) (http://www.marvasto.bologna.enea.it)

and the procedure to set up a building vulnerability

inventory in INDIRLI (2009).

6. The Investigation on Churches

Thanks to Church Authorities and Valparaıso

Firemen, three important churches, located in differ-

ent sites and built of different materials, were

investigated (La Matrız, San Francisco del Baron, Las

Hermanas de la Divina Providencia, Fig. 40). The

following steps were carried out (MAR VASTO,

2007; INDIRLI, 2009): (i) historic data collection; (ii)

laser scanner/photographic survey, visual investiga-

tion and evaluation of maintenance and damage; (iii)

vulnerability evaluation; (iv) execution of pre-

liminary numerical calculations, if necessary; (v)

indication of rehabilitation actions.

Vulnerability has been evaluated by using a well

known Italian procedure, completing specific survey

forms conceived for churches (MOLISE, 2003). The

complete study is available in Evaluation of the

vulnerability of three churches (2008) (http://www.

marvasto.bologna.enea.it).

6.1. Iglesia del Salvador, Matrız de Valparaıso

Periodically destroyed by earthquakes, tsunamis

and fires, the present fourth version of La Matrız

was constructed from 1837 to 1842 (and modifica-

tions after 1897), in the location of the original first

chapel, built after the discovery of the Valparaıso

Bay in 1559, in the ancient nucleus of the ‘‘Barrio

Puerto’’.

The church, in simple neoclassic style, is built

of adobe perimetral walls (height 12 m and thick-

ness 1.30 m), a masonry facade, with a roof of clay

tiles. The bell-tower (height 40 m), modified at the

end of the XIX century, is wooden with an iron

spiral staircase inside. The internal colonnades,

Figure 40Laser scanner, geometric, photographic and damage survey on churches



forming the naves, are also made of wood. In the

XX century a certain amount of damage occurred,

due to seismic activity, scarce maintenance and

termite attacks. Partial renovations were done

between 1971 and 1988. The most relevant damage

mechanism is in-plane shear actions in the facade,

but the global vulnerability index is about 8%,

which is a very low value. In conclusion, ‘‘La

Matrız’’ can be considered in sufficiently good

static conditions, but a general restoration is

suggested anyway for fire, materials degradation

and termite attacks prevention.

6.2. San Francisco del Baron

The neo-baroque tower and facade (brick masonry

connected by lime) were erected in 1890–1892,

thanks to the project of the architect Eduardo

Provasoli. The church faced several earthquakes

(mainly 1906 and 1985) without collapse, but severe

damage was found mainly in the bell-tower and the

arcades during our investigation. The construction

seems to be (in the facade and in the bell-tower) a

very regular masonry brickwork, but diagnostics

testing is strongly recommended. The building shows

heavy widespread structural damage and lack of

effective antiseismic protections. The most relevant

damage mechanisms are out-of-plane facade over-

turning and collapse of the bell-tower. The global

damage index is about 33%, but the local damage

index in the facade (66%) is very high. The present

damage situation must be considered very worrying,

because partial or total collapse (especially in the

bell-tower and in the facade) can occur in case of an

earthquake (i.e. medium to high magnitude seismic

excitations, as expected in the Valparaıso area); in

fact, the church is unsafe and urgently must be closed

partially or totally, implementing both prompt safety

measures and overall strengthening as soon as

possible.

After several technical meetings with Regional

and Church Authorities, a Chilean–Italian team

prepared a proposal for a prompt intervention to be

done quickly in the beginning of 2009, as an activity

developed thanks to the ‘‘MAR VASTO’’ Project

cooperation.

6.3. Las Hermanas de la Divina Providencia

The congregation of ‘‘Las Hermanas de la Divina

Providencia’’ was constructed in the ‘‘Puerto’’ after

1867. The first chapel underwent various modifica-

tions until the fire of 1880. Then, a second version

was erected on the Merced Hill (1880–1883), but

collapsed almost completely due to the 1906 earth-

quake and was later demolished. The present building

(designed by the architect Victor Auclair in a neo-

renaissance style but made by a rare primitive

reinforced concrete) began in 1907. Las Hermanas

Chapel is located in the Almendral at the Merced

foothill, exactly where the 1906 earthquake Intensity

reached the highest X value. The church was severely

damaged by the 1985 earthquake, declared unsafe

and almost completely closed without any rehabili-

tation. The monument is characterized by many

critical parameters (facade tympanum overturning,

in-plane shear mechanism in the facade, transversal

response of nave and transept, collapse of the dome,

apse overturning, apse and presbytery vaults, and

wall shear rupture). The global vulnerability index is

about 58%. The present damage situation must

considered very worrying, because partial or total

collapse (in several structural parts, due to wide-

spread weakness) can occur in case of an earthquake

(i.e. medium to high magnitude seismic excitations,

as expected in the Valparaıso area). Due to the

particular typology of the construction materials (a

primitive reinforced concrete very rare in the world),

a strengthening intervention with conventional tech-

niques can be ineffective or very invasive; a solution

should be planned only after detailed design work. As

a suggestion, an innovative solution can be imagined,

in order to reduce drastically the seismic input,

involving the introduction of a base isolation system

(with all the due precautions, avoiding elevation and

foundation wall cutting, by means of the insertion of

a new subfoundation system);, this seems possible

due to the apparent absence of a crypt.

7. Conclusions

The ‘‘MAR VASTO’’ Project showed importance

and effectiveness of GIS databases in studying



historic centers, important for their patrimonial value,

prone to natural/anthropic disasters. At the present

research stage, the methodology has been sufficiently

defined in case of earthquake (hazard mapping;

building inventory; architectonic/urban planning,

structural vulnerability analyses; intervention pro-

posals; etc.). On the other hand, further

standardization in data storing and application of

different vulnerability functions for a larger set of

building typologies (including specific algorithms

already developed by the scientific community) will

be necessary.

‘‘MAR VASTO’’ hazard and vulnerability studies

covered most of the project resources (limited in time

and funds). Starting from the above described results,

the authors will try to perform a risk analysis in the

future. In fact, the identification of a global risk factor

for a given area (or a building) needs deeper inves-

tigation. Hopefully, further projects can take

advantage of new ongoing studies such as the running

EU C26 Action (COST, 2006), in which the Vesuvius

eruption is the study case.

Finally, ‘‘MAR VASTO’’ originated important

initiatives and further cooperation between Chile and

Italy, now in progress, regarding heritage protection.

Acknowledgments

We acknowledge the contribution of the anonymous

reviewers that helped us to more precisely define

some critical points. In the framework of the ‘‘MAR

VASTO’’ Project, many people need to be thanked;

Italian team: Lorenza Bovio, Fabio Geremei, France-

sco Immordino, Lorenzo Moretti, Augusto Screpanti

and Edi Valpreda (ENEA); Claudio Alessandri,

Marcello Balzani, Daniel Blersch, Paolo Ceccarelli,

Daniel Chudak, Gianfranco Franz, Marco Miglioli,

Enrico Milani, Gian Paolo Simonini and Antonio

Tralli (University of Ferrara); Nieves Lopez Iz-

quierdo (ENEA and University of Ferrara); Claudio

Modena (University of Padua); Cristina La Mura,

Giuliano Panza, Franco Vaccari and Elisa Zuccolo

(ICTP/University of Trieste). Chilean partners: Ro-

dolfo Saragoni H., Maximiliano Astroza I. and

Thomas Sturm (Chile University of Santiago); Carlos

Aguirre A., Luis Alvarez, Raul Galindo U., Marcela

Hurtado S., Gilberto Leiva H. (Federico Santa Maria

University of Valparaıso); Geocom Santiago (Os-

valdo Neira F. and Marco Quevedo T.), which

provided Laser-Scanner equipment and personnel.

Furthermore, the support of Andres Enriquez, Dante

Gutierrez and other SHOA (‘‘Servicio Hidrografico y

Oceanografico de la Armada de Chile’’) researchers

was wonderful. During the work in Valparaıso many

local Organizations cooperated with the Italian team:

Valparaıso Municipality: above all, Mauricio Gonz-

alez L., Cristian Palma V., Carolina Avalos A.,

Claudia Zuniga J. (Valparaıso Municipality profes-

sionals at the time of ‘‘MAR VASTO’’, which joined

the Italian team also in the framework of some

bursaries provided in Italy by the Istituto Italo-Latino

Americano); Mayors of Valparaıso Aldo Cornejo and

Jorge Castro, Vice-Mayor Omar Jara A.; other

Valparaıso Municipality professionals, starting from

Paulina Kaplan D., director of the ‘‘Oficina de

Gestion Patrimonial’’, with many others; Intendencia

V Region Valparaıso: Intendente Ivan de la Maza,

Karina Englander K., Juan Carlos Garcia P. de Arce

and others; Church Authorities: Father Fernando

Candia (San Francisco Church), Mons. Gonzalo

Duarte Garcıa de Cortazar (Bishop of Valparaıso)

and others; Other Chilean Institutions: the Ministry

of Culture (‘‘Consejo Nacional de la Cultura y Las

Artes’’); Ana Maria Icaza and Francisco Saavedra

(Programa de Recuperacion y Desarrollo Urbano de

Valparaıso-PRDUV); Guillermo De La Maza

(OREMI, Civil Defense); Enzo Gagliardo L. (Head),

Vicente Maggiolo O. and colleagues (‘‘Bomba

Italia’’) of the Valparaıso (‘‘Bomberos’’) Firemen;

the Bote Salvavidas personnel (Valparaıso Sea Res-

cue Corp); the Police (‘‘Carabineros de Chile’’);

Nelson Morgado L. and many others of the Valpa-

raıso Board of Architects; other Universities

(‘‘Pontificia U. Catolica de Valparaıso’’, ‘‘U. de

Valparaıso’’, U. de Playa Ancha Valparaıso); Luis

Enriquez, Javier Troncoso (‘‘Gerencia Barrio

Puerto’’, the historic district of the City); ‘‘Junta de

Vecinos’’ of the Cerro Cordillera; Chilean profes-

sionals: above all, Milagros Aguirre D., always very

helpful and kind; Luis Bork V., Fabio Mezzano P.,

Octavio Perez A., Alfonso Salinas, Francisco Silva I.,

Gunther Suhrcke and many others; grateful thought

for the great support to: the Italian Embassy in



Santiago; Roberto Santilli, Maruzzella Giannini and

other office workers of the Italian Trade Commission

in Chile; Pablo Peragallo of the Valparaıso Italian

Community. Last but not least, special thanks to

Arcindo Santos and other professionals of BID/IADB

(Banco Interamericano de Desarrollo/InterAmerican

Development Bank). We used GMT software (Wes-

sel and Smith, 1991) in the preparation of some

figures.

REFERENCES

ASTROZA, M. I., NORAMBUENA, A., and ASTROZA, R. (2006), Rein-

terpretacion de las intensidades del terremoto de 1906, Proc.

International Conference Montessus de Ballore 1906 Valparaıso

Earthquake Centennial

ASTROZA, M. I. (2007), A re-interpretation of the Valparaıso 1906

earthquake intensities/Reinterpretacion de las intensidades del

terremoto de 1906. Proc. VI Congreso Chileno de Geotecnia,

Valparaıso, Chile, 28–30 November 2007

BERESNEV, I. A. and ATKINSON, G. M. (1997), Modeling finite-fault

radiation from the omega n spectrum. In Bulletin of the Seis-

mological Society of America, 87(1):67–84

CANCANI, A. (1904), Sur l’emploi d’une double echelle seismique

des intesites, empirique et absolue, G Beitr 2, 281–283

Cerro Cordillera (2008), Cerro Cordillera pilot project (Valpa-

raıso), MAR VASTO Project Technical Report. http://www.

marvasto.bologna.enea.it

CHOY, G. L. and DEWEY, J. W. (1988), Rupture process of an

extended earthquake sequence: teleseismic analysis of the Chil-

ean earthquake of March 3, 1985, J Geophys Res 93, 1103–1118

COMER, R. P. (1984a), The tsunami mode of a flat earth and its

excitation by earthquake sources, Geophys J Astr Soc 77, 1–28

COMER, R. P. (1984b), Tsunami generation: a comparison of tra-

ditional and normal mode approach, Geophys J Astr Soc 77, 29–

41

COMTE, D., EISENBERG, A., LORCA, E., PARDO, M., PONCE, L., SAR-

AGONI, G.R., SIGH, S.K., SUAREZ, G. (1986), The 1985 central

Chile earthquake: a repeat of previous great earthquakes in the

region?, Science 233, 449–452

CORNELL, C. A. (1968), Engineering seismic risk analysis, Bull

Seism Soc Am 58, 1583–1606

COST (2006), COST, European Cooperation in the field of

Scientific and Technical research, Transport and Urban Devel-

opment, COST Action C26: ‘‘Urban Habitat Constructions Under

Catastrophic Events’’. In Proc. Symposium on ‘‘Urban habitat

construction under catastrophic events’’, Working Group 4

‘‘Risk assessment for catastrophic scenarios in urban areas’’,

Session 6: Volcanic hazard and the Vesuvius study case; Malta,

23–25 October 2008

DECANINI, L., MOLLAIOLI, F., PANZA, G.F., ROMANELLI, F., and

VACCARI, F. (2001), Probabilistic vs deterministic evaluation of

seismic hazard and damage earthquake scenarios: a general

problem, particularly relevant for seismic isolation. Proc. 7th

International Post-Smirt Seminar on Seismic Isolation, Passive

Energy Dissipation and Active Control of Vibration of Struc-

tures, Assisi, Italy, 2–5 October, 2001

DGPS survey (2008), DGPS survey in the city of Valparaıso, MAR

VASTO Project Technical Report. http://www.marvasto.

bologna.enea.it

DOLCE, M., MARTELLI, A., and PANZA, G.F. (2005), Proteggersi dal

terremoto: le moderne tecnologie e metodologie e la nuova

normativa sismica. Seconda edizione. 21mo Secolo, 336 pagine,

ISBN 88-87731-28-4

EARTHQUAKE HAZARD (2008), Earthquake hazard in the city of

Valparaıso, MAR VASTO Project Technical Report. http://

www.marvasto.bologna.enea.it

ESPINOZA, P. (2000), Amplificacion sismica en suelos y microzo-

nificacion de los sectores planas de Vina del Mar y Valparaıso,

Civil Engineering Thesis. Departamento de Obras Civiles, Uni-

versidad Tecnica Federico Santa Maria, Valparaıso, Chile

Evaluation of the vulnerability of three churches (2008), Evalua-

tion of the vulnerability of three churches in Valparaıso and

numerical calculation, MAR VASTO Project Technical Report.

http://www.marvasto.bologna.enea.it

FAH, D. and PANZA, G.F. (1994), Realistic modelling of observed

seismic motion in complex sedimentary basins. Annali di

Geofisica 37, 1771–1797

FIRE HAZARD (2008), Fire hazard in the city of Valparaıso, MAR

VASTO Project Technical Report. http://www.marvasto.

bologna.enea.it

GIS database (2008), A GIS database for the city of Valparaıso,

MAR VASTO Project Technical Report. http://www.marvasto.

bologna.enea.it

GNDT (1999), Second Level vulnerability form for masonry

buildings/Scheda di vulnerabilita di 2� livello per edifici in

muratura, 1999

GSHAP. The Global Seismic Hazard Assessment Program,

http://seismo.ethz.ch/gshap/index.html

GUSEV, A. A. (1983), Descriptive statistical model of earthquake

source radiation and its application to an estimation of short

period strong motion, Geophys J R Astron Soc 74, 787–800

GUSEV, A. A. and PAVLOV, V. (2006), Wideband simulation of

earthquake ground motion by a spectrum-matching, multiple-

pulse technique. Proc. First European Conference on Earth-

quake Engineering and Seismology (a joint event of the 13th

ECEE & 30th General Assembly of the ESC), Geneva, Swit-

zerland, 3–8 September 2006. Paper Number: 408

GUTIERREZ, D. (2005), Advances in the Chilean tsunami warning

system and application for the TIME project on the Chilean

Coast. Presentation at GFZ Potsdam

HAMMACK, J. L. (1973), A note on tsunamis: their generation and

propagation in an ocean of uniform depth, J. Fluid Mechanics 60,

769–799

HASKELL, N. (1964), Total energy and energy spectral density of

elastic wave radiation from propagating faults, Bull Seismol Soc

Am 56, 1811–1842

INDIRLI, M. (2009), The organization of a GIS database on natural

hazards and structural vulnerability for the historic center of San

Giuliano di Puglia (Italy) and the City of Valparaıso (Chile), Int

J Archit Herit, accepted paper, publication in progress

INDIRLI, M., CARPANI, B., PANZA, G., ROMANELLI, F., and SPADONI, B.

(2006), Damage evaluation and rehabilitation of the Montorio

medieval tower after the September 14th, 2003 earthquake. Proc.

of the First European Conference on Earthquake Engineering

and Seismology (a joint event of the 13th ECEE & 30th General

Assembly of the ESC), Geneva, Switzerland, 3–8 September

2006, Paper Number: 666



KAJIURA, K. (1963), The leading wave of tsunami, Bull Earthq Res

Inst 41, 535–571

KLUGEL, J. U., MUALCHIN, L., and PANZA, G. F. (2006), A scenario-

based procedure for seismic risk analysis, Eng Geol 88, 1–22

LANDSLIDE HAZARD (2008), Geomorphological hazard in the city of

Valparaıso, MAR VASTO Project Technical Report. http://

www.marvasto.bologna.enea.it

LEE, J. J. and CHANG, J. J. (1980), Water waves generated by an

impulsive bed upthrust of a rectangular block, Appl Ocean Res 2,

165–170

LOMNITZ, C. (1971), Grandes Terremotos y Tsunamis en Chile

Durante el Periodo 1535–1955, Revista Geofısica Panamericana,

1(1), 151–178

LOMNITZ, C. (1983), On the epicenter of the great Santiago earth-

quake of 1647, BSSA 73, 885–886

MAR VASTO (2007), Risk Management in Valparaıso/Manejo de

Riesgos en Valparaıso, Servicios Tecnicos (acronym MAR

VASTO), funded by BID/IDB (Banco Inter-Americano de

Desarrollo/Inter-American Development Bank). Project ATN/II-

9816-CH, BID/IDB-ENEA Contract PRM.7.035.00-C, March

2007–October 2008. http://www.marvasto.bologna.enea.it

MENDOZA, C., HARTZELL, S., and MONFRET, T. (1994), Wide-band

analysis of the 3 March 1985 Central Chile earthquake; overall

source process and rupture history. Bull Seismol Soc Am 84(2),

269–283

MOLISE (2003), Regione Molise, CNR. Second Level form for the

evaluation of damage and vulnerability in the churches/Scheda

chiese di secondo livello per la valutazione del danno e della

vulnerabilita, 2003

OKAL, E. A. (1982), Mode-wave equivalence and other asymptotic

problems in tsunami theory, Phys Earth Planet Inter 30, 1–11

PANZA, G. F. and SUHADOLC, P. (1987), Complete strong motion

synthetics, In Seismic strong motion synthetics, computational

techniques 4, (ed. B. A. Bolt), Academic Press, Orlando, 153–

204

PANZA, G. F., VACCARI, F., COSTA, G., SUHADOLC, P., and FAH, D.

(1996), Seismic input modelling for zoning and microzoning,

Earthq Spectr, 12 529–566

PANZA, G. F., VACCARI, F., and CAZZARO, R. (1997), Correlation

between macroseismic intensities and seismic ground motion

parameters, Ann Geof 15, 1371–1382

PANZA, G. F., VACCARI, F., and ROMANELLI, F. (1999), The IUGS-

UNESCO IGCP Project 414: Realistic modeling of seismic

input for megacities and large urban areas. Episodes 22(1), 26–

32

PANZA, G.F., ROMANELLI, F., and YANOVSKAYA, T. (2000), Synthetic

Tsunami mareograms for realistic oceanic models, Geophys J Int

141, 498–508

PANZA, G. F., ROMANELLI, F., and VACCARI, F. (2001), Seismic wave

propagation in laterally heterogeneous anelastic media: theory

and applications to seismic zonation. Adv Geophys 43, 1–95

PARVEZ, I. A., VACCARI, F., PANZA, G. F. (2003), A deterministic

seismic hazard map of India and adjacent areas, Geophy J Int

155(2), 489–508

PAULATTO, M., PINAT, T., and ROMANELLI, F. (2007), Tsunami haz-

ard scenarios in the Adriatic Sea domain, Nat Hazards Earth Syst

Sci 7, 309–325

PERESAN, A., KOSSOBOKOV, V., ROMASHKOVA, L., and PANZA, G. F.

(2005), Intermediate-term middle-range earthquake predictions

in Italy: a review. Earth Sci Rev 69, 97–132.

POD’YAPOLSKY, G. S. (1968), Generation of longperiodic gravita-

tional wave in the ocean by seismic source in the crust, Izvestia

AN SSSR, Fizika Zemli 1, 7–24

ROMANELLI, F., VACCARI, F., and PANZA, G. F. (2003), Realistic

modelling of the seismic input: site effects and parametric

studies. J Seismol Earthq Eng 5(3), 27–39

ROMANELLI, F., PANZA, G.F., and VACCARI, F. (2004), Realistic

modelling of the effects of asynchronous motion at the base of

bridge piers. J Seismol Earthq Eng 6(2), 19–28

SARAGONI H. R. G. (2006), Estudio comparativo de los efectos de

los terremotos de Valparaıso de 1906 y 1985 en el barrio El

Almendral. Proc. International Conference Montessus de Bal-

lore 1906 Valparaıso Earthquake Centennial

SARAGONI, H. R. G. (2007), The 1906 Valparaıso earthquake/El

terremoto de Valparaıso de 1906. Proc. VI Congreso Chileno de

Geotecnia, Valparaıso, Chile, 28–30 November 2007

SHOA (1999), Carta de Inundacion por Tsunami para la bahia de

Valparaıso, Chile. http://www.shoa.cl/servicios/citsu/citsu.php

SOMERVILLE, P. G., SEN, M. K., and COHEE, B. P. (1991), Simulation

of strong ground motions recorded during the 1985 Michoacan,

Mexico and Valparıso, Chile earthquakes, Bull Seism Soc Am

81(1), 1–28

SSHAC (1997), Senior Seismic Hazard Analysis Committee. Rec-

ommendations for probabilistic seismic hazard analysis:

guidance on uncertainty and use of experts. NUREG/CR-6372

STURM, T. W. (2008), Valparaıso: its historic heritage and earth-

quakes/Valparaıso: su patrimonio historico y los sismos’’, Civil

Engineer Thesis, University of Chile, Faculty of Physical and

Mathematical Sciences, Department of Civil Engineering, San-

tiago de Chile, April 2008

TANNER, J. G. and SHEDLOCK, K. M. (2004), Seismic hazard maps of

Mexico, the Caribbean, and Central and South America, Tec-

tonophysics, 390, 159–175

TSUNAMI HAZARD (2008), Tsunami hazard in the city of Val-

paraıso, MAR VASTO Project Technical Report. http://www.

marvasto.bologna.enea.it

VACCARI, F., ROMANELLI, F., and PANZA, G. F. (2005), Detailed

modelling of strong ground motion in Trieste. GT&A 2, 7–

40

VERDUGO, A. I. (1995), Estudio geofisico de los suelos de fundacion

para una zonificacion sismica de Valparaıso y Vina del Mar,

Civil Engineer Thesis. Dept. Civil Engr. Fac. Ciencias Fisicas y

Matematicas, Universidad de Chile, Santiago, Chile

VERDUGO, A. (2006a), Amplificacion sısmica en los sectores planos

de Vina del Mar y Valparaıso, International Conference

Montessus de Ballore 1906 Valparaıso Earthquake Centennial,

Valparaıso, Chile

VERDUGO, R. (2006b), Caracterizacion geotecnica de Valparaıso y

su efecto en el Terremoto de 1906, International Conference

Montessus de Ballore 1906 Valparaıso Earthquake Centennial,

Valparaıso, Chile, 2006

WARD, S. N. (1980), Relationship of tsunami generation and an

earthquake source, J Phys Earth 28, 441–474.

WARD, S. N. (2002), Tsunamis, In Encyclopedia of Physical Sci-

ence and Technology (Academic Press, California)

WARD, S. N., and DAY, S. (2008) Tsunami balls: a granular

approach to tsunami runup and inundation, Commun Comput

Phys 3(1), 222–249

WESSEL, P., and SMITH, W. H. F. (1991), Free software helps map

and display data, EOS Trans AGU, 72, p. 441.



YANOVSKAYA, T. B., ROMANELLI, F., PANZA, G. F. (2003), Tsunami

excitation by inland/coastal earthquakes: the Green function

approach, Nat Haz Earth Syst Sci 3, 353–365

ZUCCOLO, E., VACCARI, F., PERESAN, A., DUSI, A., MARTELLI, A., and

PANZA, G.F. (2008), Neo-deterministic definition of seismic input

for residential seismically isolated buildings. EngGeol 101, 89–95

(Received May 15, 2009, revised March 25, 2010, accepted April 6, 2010, Published online July 6, 2010)



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