government initiatives and cooperation in seismology ... b... · government initiatives and...
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Government initiatives and cooperation in
seismology providing knowledge and training in Namibia
Bufelo Lushetile and David HutchinsThe Geological Survey of Namibia, Ministry of Mines and Energy, 1 Aviation Road, P.O Box 2168, Windhoek
INTRODUCTION
The Geological Survey of Namibia with the support of the Namibian government has become increasingly
involved in cooperative seismological projects. Many of these involve crustal studies and natural disaster
mitigation. The establishment of the National Seismic Network will enable the generation of seismic hazard maps
which will help in overall hazard mitigation strategies. More recently, the Geological Survey has begun to
introduce seismology to schools.
SEISMOLOGICAL RESEARCH – AFRICAARRAY
TSUMEB GEOPHYSICAL RESEARCH STATION
The establishment of the auxiliary seismological station at Tsumeb prompted the Geological Survey of Namibia to
increase the number of seismological stations to form a National Seismological Network (NSN). In 2000, the old
seismological station in Windhoek was refurbished and since then six further stations at Opuwo, Kamanjab, Aus,
Rundu, Tsumeb and Ariamsvlei have been established. Although these stations were strategically located to cover
as much of the country as possible, additional stations are planned for Gobabis, Karibib and Katima Mulilo to
complete the coverage. The primary objective of the NSN is to monitor seismically active faults and to compile a
catalogue of earthquakes with origin times, hypocenters and magnitude. It is planned to use these data together
with relevant historical data, to compile a seismic hazard map of the country.
ABSTRACT
The Geological Survey of Namibia has recently established a National Seismological Network with a view to
improve seismological records and ultimately generate a Seismic Hazard Map of the country. As a signatory of
the Comprehensive Nuclear-Test- Ban Treaty (CTBT), the government in cooperation with CTBTO established an
International Monitoring System (IMS) in Tsumeb consisting of Auxiliary seismological station (AS67) and
Infrasound station (IS35). Other collaborative projects include research in the Geosciences with AfricaArray, with
the main objective of studying crustal movement. In addition, the Walvis Ridge Passive Source and Active
Seismic Experiments with the German Research Centre for Geoscience (GFZ) aims to provide information on the
role of the plume-lithosphere interaction during break-up of the Southern Atlantic Ocean and the lithospheric
structure of the passive volcanic margin of Namibia. More recently, a seismology in schools project in
collaboration with the British Geological Survey has commenced to encourage learners to be aware of the
importance of the earth sciences.
WALVIS RIDGE PASSIVE AND ACTIVE SEISMIC SOURCE EXPERIMENTS
SEISMOLOGY IN SCHOOLS PROJECT
The WALPASS project is a collaborative project with the German Research Center for Geoscience (GFZ),
Potsdam, Germany. The active source experiment commenced in November 2010 and was completed in early
January 2011. Three lines were shot, one NE-SW, one NW-SE and a N-S line. These lines were over 500 km in
length and the main objective was to investigate the lithospheric structure of the passive volcanic margin of
Namibia.
The second element of the WALPASS project is the Walvis Ridge Passive Source experiment in which 29
temporary seismic stations have been deployed at roughly 50-100 km spacing. This temporary seismic network
will be operational for 18 months and will monitor the local seismicity in the north western part of the country. The
seismological data will also provide information on the role of plume-lithosphere interaction during the break-up of
the Southern Atlantic Ocean.
The Geological Survey of Namibia, in collaboration with the British Geological Survey, has recently introduced
a seismology in schools project. The main aim of the project is to increase the interest of pupils in science
particularly in physics and to advance career possibilities in the geosciences.
As a first step, in April 2010, two-one component seismometers were delivered to Etosha Secondary school in
Tsumeb and the Walvis Bay Private school, following teachers training at the Geological Survey in Windhoek.
During the next five years additional seismometers will be purchased and the programme rolled out to
schools in rural areas. Once established the schools will be encouraged to form a schools seismological
network and locate seismological events in Namibia and worldwide.
AfricaArray is public-private partnership supporting training and research in earth, atmospheric, and space
sciences in Africa founded by The University of Witwatersrand, and Council of Geoscience of South Africa and
Penn. State University, USA. As part of this partnership one of the seven NSN stations, Rundu, was recently
chosen to provide seismic data to AfricaArray and consequently the seismological equipment was upgraded. In
addition, GPS and Meteorological sensors were installed to facilitate weather pattern studies. The seismological
data will contribute toward a more complete image of the African mantle and hence an advanced understanding
mantle dynamics.
Figure 4: GPS and Meteorological sensors in Rundu
Temporary station distribution map (left) and a recently deployed station (right)
Distribution map of seismic stations (yellow dots) Teachers receiving training on how to set-up the seismometer (left) and a running seismometer at Etosha Secondary School
A seismological station was first established at Tsumeb in 1993 by United States Geological Survey (USGS) as
part of the Global Seismic Network to monitor world-wide earthquakes. After Namibia ratified the Nuclear Test Ban
Treaty (CTBT) in 2001, the Tsumeb Geophysical Research Station was selected to become a part of the
international monitoring network, with the establishment of an Infrasound Station and upgrading of the existing
seismological equipment. The IS35NA (Infrasound Station) and the AS67-TSUM (Auxiliary Seismic Station) were
certified in June and July 2004, respectively, since when have been transmitting data to the National Data Centre
in Windhoek and, simultaneously, to the International Data Centre in Vienna, Austria. This data contributes
towards the monitoring and detection of both sub-surface and atmospheric nuclear explosions.
The Tsumeb station also monitors magnetic secular variation in co-operation with the Hermanus Magnetic
Observatory of South Africa and cosmic emissions in conjunction with the University of Potchefstroom, South
Africa
NATIONAL SEISMOLOGICAL NETWORK
Instruments at the Windhoek station.
VSAT antenna