HR: 16:45h
AN: G44A-04    [Abstracts]
TI: Post-seismic deformation after the 2003 Bam, Iran earthquake
AU: * Fielding, E J
EM: Eric.J.Fielding@jpl.nasa.gov
AF: Jet Propulsion Laboratory, Caltech, 4800 Oak Grove Drive MS 300-233, Pasadena, CA 91109 United States
AU: Funning, G
EM: gareth@seismo.berkeley.edu
AF: Dept. Earth and Planetary Sci, Univ. California, Berkeley, McCone Hall, Berkeley, CA 94720 United States
AU: Talebian, M
EM: talebian@gsi-iran.org
AF: Geological Survey of Iran, P.O. Box 13185-1494, Tehran, 1 Iran (Islamic Republic of)
AU: Lundgren, P
EM: Paul.Lundgren@jpl.nasa.gov
AF: Jet Propulsion Laboratory, Caltech, 4800 Oak Grove Drive MS 300-233, Pasadena, CA 91109 United States
AU: Li, Z
EM: zhli@ge.ucl.ac.uk
AF: Dept. of Geomatic Engineering, University College London, Gower Street, London, WC1E 6BT United Kingdom
AU: Burgmann, R
EM: burgmann@seismo.berkeley.edu
AF: Dept. Earth and Planetary Sci, Univ. California, Berkeley, McCone Hall, Berkeley, CA 94720 United States
AU: Wright, T J
EM: Tim.Wright@earth.ox.ac.uk
AF: Dept. Earth Science, University of Oxford, Parks Road, Oxford, OX1 3PR United Kingdom
AB: The December 2003 Mw 6.6 earthquake that devastated Bam, Iran involved several meters of slip on a previously unknown fault beneath the city. The outstanding surface conditions for InSAR and frequent coverage by Envisat ASAR provide an opportunity to map the ground deformation and study the time history in the two years since the earthquake. Envisat data from two nearly opposite lines of sight allow the separation of vertical motion from horizontal east-west motion. The post-seismic surface deformation associated with the 2003 earthquake rupture is one order of magnitude smaller than the co-seismic deformation, so the signal is much closer to the noise due to atmospheric variations. For the day-time ASAR over Bam we are exploring the use of MERIS water vapor measurements to derive an atmospheric correction for the InSAR data to better separate the ground deformation signal. Preliminary analysis shows that most of the ground deformation happened in the first six months after the earthquake, which is similar to the short decay time of post-seismic deformation observed after the September 2004 Parkfield, California earthquake. The distribution of deformation indicates at least two different processes were involved, at different depths in the crust. A narrow zone along the observed surface ruptures of the 2003 earthquake moved downward in the months afterward. This subsidence was not restricted to the areas of compressional steps in the co-seismic rupture so it is unlikely to be explained by poroelastic rebound effects. This deformation is restricted to the area of surface ruptures so it is related to the rupture of the surface layer. Longer wavelength deformation at the ends of the main subsurface co-seismic rupture inferred from InSAR is apparently due to deformation at several km depth, probably afterslip on the main fault plane.
DE: 1207 Transient deformation (6924, 7230, 7240)
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 1242 Seismic cycle related deformations (6924, 7209, 7223, 7230)
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
DE: 8163 Rheology and friction of fault zones (8034)
SC: Geodesy [G]
MN: Fall Meeting 2005