Seismic Scattering from Geological Scatterers in the IAESZ Region, West Turkey

Seismic scattering is commonly observed and results from wave propagation in a heterogeneous medium. Body-to-surface wave scattering originates from strong lateral heterogeneity. In this study, we present the results of an analysis on body-to-surface wave scattering in the region of Turkey, performed using teleseismic recordings from ۸۲ broadband stations of temporary and permanent networks. The type of scattering we consider is the conversion of the SH wave to Love wave from geological scatterers. For the earthquake source, we use the ۲۷ July ۲۰۱۴ earthquake (Mw=۶.۴) in the Atlantic Ocean. We apply phase coherence analysis to broadband waveforms to detect coherent signals associated with body-to-surface wave scattering. The scattered Love waves in our study traveled at a dominant period of ~۱۰ s and a velocity of ~۳.۱۷ km/s. We utilize the converted surface waves to map strong lateral heterogeneities in the West of Turkey. We located the sources of scattering by back-propagating the beamformed energy using a straight-ray approximation for the earthquake. Back projection suggests that strong scattering is associated with the IAESZ (Izmir-Ankara-Erzincan Suture Zone) in the West of Turkey. This major suture zone and its steep topographic slope could play a role in scattering seismic waves. The results show that strong lateral heterogeneities in seismic wave velocity or density, such as suture zone and fault zone structures, are potentially strong scatterers.

کلیدواژه ها:

Lateral heterogeneities ، Wave Scattering ، Scatterer ، IAESZ ، Back Projection