CASE STUDY OF SMALL SCALE SURFACE DEFORMATION DETECTION USING

ALOS PALSAR DIFFERENTIAL INTERFEROMETRY

Ryoichi Furuta

RESTEC,1-9-9 Roppongi,Minato-ku,106-0032 Tokyo, Japan,Email:furuta_ryoichi@restec.or.jp

ABSTRACT

Monitoring of small scale surface deformation is very

important thing to prevent disaster of surrounding of

housing area. However, number of ground observation

stations for subsidence/landslides are less than

seismic/crustal deformation monitor. Application of

DInSAR technology has prospects to improve and

interpolate this situation. In this paper, capabilities of

DInSAR for small scale surface deformation detection

have been focused on. Three case studies were

discussed to understand it. In the case of "the Niigata

Chuetsu-oki Earthquake in 2007", small scale surface

deformation due to liquefaction and landslide was

detected with the crustal deformation. And, in case of

analysis of surrounding of coal mine site, subsidence

due to overuse of ground water was detected and source

of deformation was estimated by numerical analysis.

Moreover, reactivated landslide was detected through

the monitor of active landslide.

1. INTRODUCTION

Monitoring of small scale surface deformation is very

important thing to prevent disaster of surrounding of

housing area. However, number of ground observation

stations for subsidence/landslides are less than

seismic/crustal deformation monitor. Application of

DInSAR technology has prospects to improve and

interpolate this situation. Advanced Land Observing

Satellite (ALOS) carries L-band synthetic aperture radar

named Phased Array Type L-band Synthetic Aperture

Radar (PALSAR). PALSAR have been bringing many

excellent results in case of crustal deformation detection

by DInSAR analysis [1]. From these results, capability

of large surface deformation detection including high

vegetation area is known. And also, the capability of

DInSAR of L-band SAR for small scale surface

deformation detection was confirmed from past case

studies using Japanese Earth Resources Satellite -1

(JERS-1) SAR [2], [3],[4].

In this paper, capability of DInSAR of PALSAR for

small scale surface deformation detection is focused on,

and discussing it based on three case studies. In present

years, many damages of housing area from small scale

surface deformation occurred due to seismic motion.

Based on the result of DInSAR of the Niigataken

Chuetsu-oki Earthquake in 2007, interpretation of small

scale surface deformation is analyzed. And, overuse of

ground water is one of the factors of land subsidence. In

order to detect subsidence of surrounding of coal mine

site, PALSAR DInSAR analysis is applied, and

numerical model is applied to understand sources of

subsidence. Moreover, author have been monitoring

creep type landslide in Japan using JERS-1 SAR and

PALSAR since 2003. Through this activity, reactive

landslide was detected near the test site. The mechanism

of this reactive landslide is analyzed.

2. CASE STUDIES OF SMALL SCALE SURFACE DEFORMATION DETECTION

2.1.2.1.2.1.2.1. Small surface deformation at the Niigataken Chuetsu-oki Earthquake in 2007

In 16 July 2007, M6.8 earthquake struck to Chuetsu

district of Niigata prefecture, Japan. JAXA observed the

area of epicenter by ALOS PALSAR in 19 July 2007.

Crustal deformation due to this earthquake was

analyzed by PALSAR DInSAR using observation data

of 19 July 2007 and 19 January 2007. In order to

analyze DInSAR, SIGMA-SAR [5] processor was used.

Fig. 1 shows the detected crustal deformation that LOS

shortening in northern part of fringe area and LOS

lengthen at southern part of fringe area was obtained.

Based on the report of ground survey, many small scale

surface deformations of surrounding of housing area

were confirmed over the seaboard region [6]. Fig. 2

shows the enlarged view of damage area of seaboard

region. A landslide occurred in mountain side and very

complicated fringe pattern in flatland was confirmed.

This fringe pattern was caused by liquefaction with

ground flow. In case of ground liquefaction, surface

condition shows several patterns as subsidence,

upheaval, flow, and so on. This result shows these

deformations.

2.2.2.2.2.2.2.2. Small surface deformation of surrounding of coal mine site

Due to the overuse of ground water, subsidence

occurred in surrounding of coal mine site. Especially,

subsidence at housing site is current problem at the

northern part of China. ALOS PALSAR DInSAR was

applied to detect subsidence of surrounding of two of

coal mine sites in the northern China, and subsidence at

housing area were detected as Fig. 3. In order to

estimate sources of subsidence, numerical analysis

based on elastic model was applied to site-2, Fig. 3(b).

_____________________________________________________ Proc. ‘Fringe 2009 Workshop’, Frascati, Italy, 30 November – 4 December 2009 (ESA SP-677, March 2010)

©METI, JAXA processed by SIGMA-SAR

-5.9cm +5.9cm-5.9cm +5.9cm

Figure 1. Detected large scale surface deformation as

crustal deformation

Landslide

Landslide and subsidence

due to liquefaction

©METI, JAXA processed by SIGMA-SAR

-5.9cm +5.9cm-5.9cm +5.9cm

Figure 2. Small surface deformation around seaboard

area

From the result of numerical analysis, subsidence

occurred by three sources can be estimated. And also,

these sources distributed in different depth can be

estimated as Fig. 4. The approach of combination use of

numerical analysis and DInSAR has a possibility of

factor estimation of subsidence, and also it is effective

as a means of supplementing the result of DInSAR.

2.3.2.3.2.3.2.3. Landslide monitoring of Shikoku district, Japan Since 2003, authors have been monitoring the one of the

landslides in Shilkoku district, Japan, named Zentoku

©METI, JAXA processed by PALSAR Fringe

Az.

Rg.

-5.9cm +5.9cm

©METI, JAXA processed by PALSAR Fringe

Az.

Rg.

-5.9cm +5.9cm-5.9cm +5.9cm

(a) Site-1

©METI, JAXA processed by PALSAR Fringe

Az.

Rg.

-5.9cm +5.9cm

©METI, JAXA processed by PALSAR Fringe

Az.

Rg.

-5.9cm +5.9cm-5.9cm +5.9cm

(b)Site-2

Figure 3. DInSAR results of coal mine site in the

northern part of China

1

2

3X, Y

Depth

Simulation

-5.9cm +5.9cm

DInSAR

1

2

3X, Y

Depth

Simulation

-5.9cm +5.9cm-5.9cm +5.9cm

DInSAR

Figure 4. Result of numerical analysis of site-2 based on

elastic model

landslide using JERS-1 SAR and ALOS PALSAR

DInSAR (e.g. [2], [3], [4]). Through this monitoring

activity, reactivated landslide was detected near the

Zentoku landslide in 2007. Fig. 5 shows the results of

ALOS PALSAR DInSAR using observation data of 14

January 2007 and 17 January 2008. From the result, two

active landslide blocks was confirmed. And these

landslide blocks was corresponding to landslide terrain

map provided by National Research Institute of Earth

Science and Disaster Prevention (NIED), Japan [7].

From the landslide terrain map, it can be considered that

each landslide blocks were link together. From both

DInSAR result and landslide terrain map, it can be

considered that the upper block was behaved together

with lower block. In this case, it can be considered that

lower block was moved to the direction of bottom of

slope and also upper block was deformed with

subsidence and flow.

Figure 5. Detected reactivated landslide by ALOS

PALSAR DInSAR (with landslide terrain map (©NIED))

3. CONCLUSIONS

ALOS PALSAR brings excellent results of detection of

small scale surface deformation as well as large scale

surface deformation through the case studies. Especially,

it is effective to detect very slow landslide movement at

high vegetation area. Detection of reactivated landslide

is the most prospects to DInSAR analysis. In order to

detect reactivated landslides, continuous monitoring is

necessary. And, it was confirmed that combination use

of DInSAR and numerical model is effectively to

understand mechanism of small scale surface

deformation. An approach of combination use of

DInSAR and numerical model has a possibility to

advanced small surface deformation detection analysis

by DInSAR.

4. ACKNOWLEDGEMENTS

ALOS PALSAR data used in this research are courtesy

of JAXA projects of disaster monitoring activity and

ALOS research activity. And I’m grateful to Dr.

Masanobu Shimada, JAXA/EORC, for use of his

SIGMA-SAR interferometry software.

5. REFERENCES

1. Japan Aerospace Exploration Agency, Earth

Observation Research Center, Image Gallery,

online at

http://www.eorc.jaxa.jp/ALOS/en/gallery/new_ar

r.htm (as of 29 October 2009)

2. R. Furuta, M. Shimada (2006), A case study of landslide monitoring, and prospects of the utilization of ALOS data for multi-scale landslide monitoring, Asian Journal

of Geoinformatics, Volume 6, No.4, pp.71-75.

3. Ryoichi FURUTA, Masanobu SHIMADA, Takeo TADONO, Manabu WATANABE, (2005),

Interferometric capabilities of ALOS PALSAR

and its utilization, Proceedings of FRINGE 2005

Workshop (CD-ROM).

4. Ryoichi Furuta, Masanobu Shimada, Takeo Tadono, Manabu Watanabe (2005), Application of

Differential SAR Interferometry for Takisaka

Landslide，Proceedings of 31th Remote Sensing

Symposium, pp.24-27.

5. Masanobu Shimada (1999), Verification processor for SAR calibration and interferometry, Adv.

Space Res. Vol. 23, No. 8, pp. 1477-1486.

6. Mamoru Koarai and Hirosi Sato (2007), Field Survey Report of the Niigataken Chuetsu-oki

Earthquake in 2007, Geographical Survey

Institute of Japan (GSI), online at

http://cais.gsi.go.jp/Research/geoinfo/field_Chue

tsu-oki.pdf (as of 3 August 2007).

7. National Institute of Earth Science and Disaster Prevention, Landslide Distribution Maps, online

at http://lsweb1.ess.bosai.go.jp/ (as of 17

September 2009).