Study of crustal structure in the Caucasus and Caspian regions using receiver functions -
Rumi Takedatsu;
B.S. Candidate-
Advisor Dr.Rob Mellors:
The Eurasia-Arabia collision has created complex tectonics and structure in the Caucasus and Caspian region. In particular, Caspian Basin has a very different lithospheric structure from the surrounding region and the origin of the basin and nearby structures, such as the Kura Depression, are not well understood. This study will map the main crustal structure and estimate Moho depth under each seismic station using receiver functions. Receiver functions are a well-established technique to determine the boundary between crust and upper mantle (Moho) using three-component broadband seismograms. Using seismic data from 14 broadband stations in Azerbaijan, we generate receiver functions for 90 events. The Moho depth beneath each is determined by forward modeling the receiver functions using a reflectivity method and a two-layer crust. The receiver functions show clear indications of dipping structure as well as thick sediments under many stations which make modeling difficult. The preferred results show Moho depths of 37 - 43 km under the Greater Caucasus, 46 km under the Lesser Caucasus, 34 – 42 km in the Kura Depression, and 31 – 35 km along the western boundary of the South Caspian Basin. Crustal thickness thins towards the Caspian.
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