Akademik Veri Yönetim Sistemi
6th International Conference on Earthquake Engineering and Seismology, Kocaeli, Türkiye, 13 - 15 Ekim 2021, ss.1-10, (Tam Metin Bildiri)
The
East Anatolian Fault zone is one of the active fault zone causing several destructive
earthquakes in the instrumental and historical periods. This seismic activity is
generally associated with the moving of the Arabian, Eurasian, and African
plates. The region has recently experienced a strong
earthquake which is the Elazığ earthquake
(Mw=6.8) that occurred on January
24, 2020, according to the Disaster and
Emergency Management Presidency (AFAD). Developed regional shear-wave
velocity distribution is very important for a better seismic characterization (seismic
locations, source parameters, and focal depths), regional seismicity, and
seismic hazard assessment. The main goals of this study are to identify the
crust and upper mantle S-wave velocity structure along the EAFZ and to compare the results
of two different joint inversion algorithms. As the first method, the joint
inversion procedure developed by Julia et al. (2000) is used. This method involves jointly inverting the P-Receiver Functions and
Rayleigh wave phase velocities. As the second method, it is
applied simultaneous inversion of the P-Receiver Functions and S-Receiver
Functions (PRFs and SRFs), similar to the simulated annealing method. In this
technique, PRFs are obtained from Vinnik (1977), while SRFs are computed from
Farra and Vinnik (2000).
For the data sets, the broadband
stations of the AFAD (FRT,
MAYA, AZEY, AKCA, NAR, RHAN) and Kandilli
Observatory and Earthquake Research Institute (KARO, BNGB, SVRC) are used to
obtain regional (Δ ≤ 10°) and teleseismic (30° ≤ Δ ≤ 90°) events. According to the
results, the first algorithm reveals more effective results in the upper-crust,
while the second algorithm includes more effective results in the uppermost
mantle. The crustal low-velocity zones beneath the stations are
observed at a depth of ~12 km. The
depth distribution of earthquake hypocenters generally occurs between 10 and 20
km in the time interval 2000-2020. This shallow seismicity is compatible with
S-wave velocity variations and strike-slip motion. The crust-mantle transition
along the EAFZ varies from 32 km to 44 km. Finally, this study gives that the lithospheric
S-wave velocity structure corresponds with the regional tectonics of the
studied region.