HR: 14:40h
AN: S53C-05    [Abstracts]
TI: Seismicity and Improved Velocity Structure in Kuwait
AU: * Gok, R
EM: gok1@llnl.gov
AF: Atmospheric, Earth and Energy Department, Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, 94550 United States
AU: Rodgers, A
EM: rodgers7@llnl.gov
AF: Atmospheric, Earth and Energy Department, Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, 94550 United States
AU: Al-Enezi, A
EM: aenezi@safat.kisr.edu.kw
AF: Environment and Urban Development Division, Kuwait Institute for Scientific Research, Safat, Safat, 13109 Kuwait
AB: The Kuwait National Seismic Network (KNSN) began operation in 1997 and consists of nine three-component stations (eight short-period and one broadband). Although the region is largely believed to be aseismic, considerable local seismicity is recorded by KNSN. Seismic events in Kuwait are clustered in two main groups, one in the south and another in the north. The KNSN station distribution is able to capture the southern cluster within the footprint of the network but the northern cluster is poorly covered. We have analyzed KNSN recordings of nearly 200 local events to improve understanding of seismic events and crustal structure in Kuwait, performing several analyses with increasing complexity. First, we obtained an optimized one-dimensional (1D) velocity model for the entire region using the KNSN bulletin locations. We observe a consistency of this model with the model obtained from the joint inversion of receiver function and surface wave group velocities. Crustal structure is capped by the thick (~ 7 km) sedimentary rocks of the Arabian Platform and normal velocities for stable continental crust. We then used a double-difference tomography technique (tomoDD) and the optimized 1D model to jointly locate the events and estimate three-dimensional (3D) structure by tomographic inversion. TomoDD is based on hypoDD relocation algorithm and it makes use of both absolute and relative arrival times. We obtained ~1500 absolute P and S arrival times and ~3200 P and S wave arrival time differences. Finally, we calculated Mw's of nearly 100 events using the coda magnitude technique of Mayeda et al., (2003). Although the current studies will not be able to reveal the source of current seismicity in Kuwait, we obtain a considerable amount of improvement in the velocity model and the reduced scatter of travel time residuals relative to the routine KNSN bulletin. The new velocity model and moment magnitudes will be utilized in ground motion prediction and hazard estimate studies in the region. *This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.
DE: 7203 Body waves
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 7270 Tomography (6982, 8180)
DE: 8123 Dynamics: seismotectonics
SC: Seismology [S]
MN: Fall Meeting 2005