Complex Wave Propagation Revealed by Peak Ground Velocity Maps in the Caucasus Area

ABSTRACT In 2013, a new network of broadband seismic stations was deployed in the Caucasus region. Broadband displacement data are inverted for the seismic moment tensor of two medium‐sized earthquakes occurring in northeast Georgia (17 September 2013, M w  5.1) and northern Armenia (26 May 2014, M w  3.6), respectively. The peak ground velocity (PGV) is estimated for each station that recorded the seismic events. We then construct shake maps for those seismic events. Those time‐dependent shake maps can provide not only the information on the initial rupture, the ground response as well as the nature of the soil (soft or stiff), but also the potential directivity of the rupture. The goal of the study is to provide a comprehensive image of the spatial distribution of the PGV in the Caucasus region from small‐to‐moderate earthquakes, as well as to estimate the rupture directivity for the considered seismic events. Our results demonstrate a good consistency between the source mechanism and the regional tectonics, and a directivity of the rupture perpendicular to the faults.