HR: 11:20h
AN: S52A-05    [Abstracts]
TI: The 22 June 2002 Changureh (Avaj) Earthquake in Qazvin Province, NW Iran: Epicentral Re-location, Source Parameters, Surface Deformation and Geomorphology.
AU: * Walker, R T
EM: rwalker@esc.cam.ac.uk
AF: Bullard Laboratories University of Cambridge, Madingley Road, Cambridge, CB3 0EZ United Kingdom
AU: Bergman, E
EM: bergman@seismo.com
AF: University of Colorado at Boulder, Department of Physics, Boulder, CO 80309-0390 United States
AU: Jackson, J A
EM: jackson@esc.cam.ac.uk
AF: Bullard Laboratories University of Cambridge, Madingley Road, Cambridge, CB3 0EZ United Kingdom
AU: Ghorashi, M
EM: mghorashi@hotmail.com
AF: Geological Survey of Iran, Azadi Square Meraj Avenue , Tehran, 13185-1494 Iran (Islamic Republic of)
AU: Talebian, M
EM: morteza100@yahoo.com
AF: Geological Survey of Iran, Azadi Square Meraj Avenue , Tehran, 13185-1494 Iran (Islamic Republic of)
AB: The Mw 6.4 Changureh (Avaj) earthquake occurred on the 22 June, 2002 in Qazvin province, NW Iran. We use observations from seismology, field investigation and analysis of satellite imagery and digital topography to suggest that slip on a previously unrecognised thrust fault (herein named the Abdarreh fault) was responsible for the earthquake. Inversion of long-period P and SH body-wave seismograms shows rupture on a thrust fault dipping 49 degrees to the southwest and with a centroid depth of about 10 km. Multiple-event relocation of the main-shock and aftershock epicentres, and discontinuous surface ruptures observed after the earthquake are compatible with a NW propagating rupture on a SW-dipping thrust, but maximum recorded displacements are much less than expected from seismology, suggesting that much of the slip failed to reach the surface and was accommodated as folding at the surface instead. Long-term folding is difficult to see in the topography of the epicentral region as the Abdarreh fold is growing through a relict Neogene topography. Anticlinal uplift can however be inferred from drainage disruption and stream incision. The 22 June, 2002 Changureh earthquake shows the importance of being able to interpret diagnostic features of active faulting in the landscape.
DE: 7230 Seismicity and seismotectonics
DE: 8040 Remote sensing
DE: 8102 Continental contractional orogenic belts
DE: 8107 Continental neotectonics
SC: Seismology [S]
MN: 2004 AGU Fall Meeting