Earthquake focal parameters and lithospheric structure of the anatolian plateau from complete regional waveform modeling

Rodgers, Arthur

Lawrence Livermore National Laboratory

关键词: Topography;    Attenuation;    99 General And Miscellaneous//Mathematics, Computing, And Information Science;    Wave Forms;    Thickness;   

DOI  :  10.2172/15006169
RP-ID  :  UCRL-ID-141864
RP-ID  :  W-7405-ENG-48
RP-ID  :  15006169

美国|英语

来源: UNT Digital Library

【 摘 要 】

This is an informal report on preliminary efforts to investigate earthquake focal mechanisms and earth structure in the Anatolian (Turkish) Plateau. Seismic velocity structure of the crust and upper mantle and earthquake focal parameters for event in the Anatolian Plateau are estimated from complete regional waveforms. Focal mechanisms, depths and seismic moments of moderately large crustal events are inferred from long-period (40-100 seconds) waveforms and compared with focal parameters derived from global teleseismic data. Using shorter periods (10-100 seconds) we estimate the shear and compressional velocity structure of the crust and uppermost mantle. Results are broadly consistent with previous studies and imply relatively little crustal thickening beneath the central Anatolian Plateau. Crustal thickness is about 35 km in western Anatolia and greater than 40 km in eastern Anatolia, however the long regional paths require considerable averaging and limit resolution. Crustal velocities are lower than typical continental averages, and even lower than typical active orogens. The mantle P-wave velocity was fixed to 7.9 km/s, in accord with tomographic models. A high sub-Moho Poisson's Ratio of 0.29 was required to fit the Sn-Pn differential times. This is suggestive of high sub-Moho temperatures, high shear wave attenuation and possibly partial melt. The combination of relatively thin crust in a region of high topography and high mantle temperatures suggests that the mantle plays a substantial role in maintaining the elevation.