HR: 1340h
AN: S13B-1057    [Abstracts]
TI: Crustal Attenuation Within The Anatolian Plateau And Surrounding Regions
AU: * Zor, E
EM: zore@missouri.edu
AF: Department of Geological Sciences, University of Missori-Columbia, Columbia, MO 65211 United States
AU: Sandvol, E A
EM: sandvole@missouri.edu
AF: Department of Geological Sciences, University of Missori-Columbia, Columbia, MO 65211 United States
AU: Xie, J
EM: xie@ldeo.columbia.edu
AF: Lamont Doherty Earth Observatory, Columbia University, Palisades, NY 10964 United States
AU: Mitchell, B
EM: mitchbj@eas.slu.edu
AF: Department of Earth and Atmospheric Sciences, St. Louis University, St. Louis, MO 63103 United States
AU: Turkelli, N
EM: turkelli@boun.edu.tr
AF: Department of Geophysics, Kandilli Observatory and Earthquake Research Institute, Bogazici University, Istanbul, 81220 Turkey
AB: In order to map variations in crustal and uppermost mantle attenuation for a given region, we have collected waveform data from a wide variety of sources like national networks, GSN stations, various permanent and temporary sites in the Middle East (Jordan, Saudi Arabia), Caspian Sea region. A large number of digital seismograms (approximately 8000) yields a dense path coverage for all four regional seismic phases throughout most of the northern portion of the Arabian plate as well as the Anatolian Plateau. This dense coverage should dramatically improve the resolution of our Q model. Moreover, it allows the bias in Q measurements to be minimized by using methods that are more reliable, but require restrictive path geometries. The most efficient method for developing a lithospheric attenuation model is to use standard two-station method using computed Fourier spectra for the corresponding regional seismic phases: Pn, Pg, Sn, and Lg for many events and paths. This method virtually eliminates source, site and path effects which is even more critical for paths through a region such as the Middle East, where both crustal and uppermost mantle attenuation are very high. We began working on Lg with this method which allow us to obtain a model of Qo and n (Lg Q at 1 Hz and its power-law frequency dependence, respectively). Subsequently, the tomography will yield high-resolution maps of laterally varying Qo. This study will also yield a regionalized Q models for Pg, Pn and Sn. Our strategy is to begin in regions where we have very dense two station ray paths; therefore, we have chosen to begin our focus on the eastern Anatolian plateau and northern Arabian plate where we have data from Kandilli Observatory and Earthquake Research Institute, Jordanian Seismic Observatory and from the temporary PASSCAL network in eastern Turkey (ETSE). This region has been shown to be a region of anomalously high Lg and Sn attenuation and blockage. Our Q-models will be used to quantify the level of attenuation within the Anatolian plateau.
DE: 7220 Oceanic crust
DE: 7200 SEISMOLOGY
DE: 7205 Continental crust (1242)
DE: 7218 Lithosphere and upper mantle
SC: Seismology [S]
MN: 2004 AGU Fall Meeting