HR: 0800h
AN: G51C-0624    [Abstracts]
TI: Shallow coseismic deformation in Western Australia observed with InSAR and seismic data
AU: * Dawson, J
EM: john.dawson@anu.edu.au
AF: Research School of Earth Sciences, ANU, Bldg 61 Mills Road Acton, Canberra, ACT 0200, Australia
AU: * Dawson, J
EM: john.dawson@anu.edu.au
AF: Geoscience Australia, Cnr Jerrabomberra Ave & Hindmarsh Drive Symonston, Canberra, ACT 2601, Australia
AU: Cummins, P
EM: phil.cummins@ga.gov.au
AF: Geoscience Australia, Cnr Jerrabomberra Ave & Hindmarsh Drive Symonston, Canberra, ACT 2601, Australia
AU: Tregoning, P
EM: paul.tregoning@anu.edu.au
AF: Research School of Earth Sciences, ANU, Bldg 61 Mills Road Acton, Canberra, ACT 0200, Australia
AB: The South West Seismic Zone (SWSZ) located in Western Australia, is an area of high intra-plate earthquake activity. The area is thought to pose significant seismic hazard since the SWSZ is near to the city of Perth, a population centre of 1.5 million people, and it encompasses the source area of the magnitude 6.8 Meckering earthquake of 1968. We have undertaken an analysis of interferometric satellite radar (InSAR) observations, from the ENVISAT satellite, of a seismically active area of the SWSZ. We have observed a shallow, 1 km depth, magnitude 4.4, reverse fault earthquake near the township of Kalannie. The earthquake generated maximum line-of-sight coseismic displacements of 28 mm, visible in both descending and ascending passes. We reduce atmospheric artifacts through a time series analysis of the InSAR data and develop an analysis strategy which deals with transient signal stability associated with agricultural activity in the study area. This is the first observation of a coseismic displacement field associated with an Australian earthquake using modern satellite geodetic tools. It provides important constraints on the earthquake hypocentre and source mechanism that can be used to calibrate techniques for determining earthquake magnitude and location that are used in routine earthquake monitoring of the SWSZ. We make a comparison of the InSAR determined earthquake mechanism to seismic observations of the event.
DE: 1243 Space geodetic surveys
DE: 7215 Earthquake source observations (1240)
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
SC: Geodesy [G]
MN: 2007 Fall Meeting