MALAGASY SEISMIC NETWORK RAZAFINDRAKOTO Hoby RAMANANTSOA Andry Metadata

MALAGASY SEISMIC NETWORK RAZAFINDRAKOTO Hoby – RAMANANTSOA Andry Metadata 2009

OUTLINE Historical of the Malagasy seismic network Data processing Conclusion

SEISMIC STATIONS IN MADAGASCAR 1898: TAN 1971: AVY 1972: VTY, FRR 1978: OBY 1982: ABM 1994: ATG 1995: MDV 2001: FIRM 2007: ABPO 2008: FOMA The Malagasy first seismic station was installed in Antananarivo in 1898. The network has been improved and composed now by 11 stations.

Seismometer ZM 500 Seismometer 3 components ZM 500 and HM 500

OUTLINE Historical of the Malagasy seismic network Data processing Conclusion

LOCATION OF SEISMIC EVENTS Until 1972 EYEWITNESS REPORT 1972 – 1988 GEOMETRICAL METHOD 1988 – 2001 ISIS LEAST SQUARE METHOD 2001 – now ONYX

SEISMICITY MAP OF MADAGASCAR Seismotectonic map and location of the seismic network: 1 D faults; 2 D thrusts; 3 D main towns; 4 D seismic stations; 5 D seismic activity for magnitudes 4. 0 located by the Malagasy array between 1979 and 1994; 6 D known earthquakes of magnitude 5. 0 between 1914 and 1994; 7 D intensities VII recorded between 1897 and 1960; 8 D focal mechanisms (Bertil et al. , 1998) Seismicity map of Madagascar between 1975 and 2006 (Rakotomalala, 2007)

OUTLINE Historical of the Malagasy seismic network Data processing Conclusion

The more extended the network is, the better the results are Suggestion: -to use all the stations for the seismic location - to create a new database for the data from all the stations in Madagascar -enlarge the network to the western part -Data exchange in order to study the plate tectonics

THANK YOU MISAOTRA TOMPOKO