Seismic Network Magnitude Improvement in Georgia

Session: Regional Earthquake Centers: Highlights and Challenges
Type: Oral
Date: 4/28/2020
Time: 05:15 PM
Room: 215 + 220
Description: 

The Greater Caucasus is in a continental collision zone and seismically very active region comprising various tectonics units. It is one of the youngest mountain systems on earth yet the digital seismic network in the Caucasus countries has been only improved recently. National networks in the region deployed new seismic stations and established stronger collaboration with real-time data exchange. In 2017, a temporary IRIS/PASSCAL deployment, ‘The Uplift and Seismic Structure of the Greater Caucasus’ started providing increased amount of data in the region. This project is partially supported by the US Department of Energy through the Science and Technology Center in Ukraine (STCU). Armenia, Azerbaijan, Georgia and the US team jointly deployed 53 seismic stations in three phases. In this study, we analyze nearly 150 events with ML>3.5 to derive moment magnitude (Mw). We additionally used data from national networks in Georgia and Azerbaijan (2014-2018), Georgia (2017-2020) and Global Seismographic Network (GSN) (1992-2019). We first relocate all events in the catalog. We then derive moment magnitude (Mw) using 1D coda calibration technique using Coda Calibration Tool (CCT) developed by Lawrence Livermore National Laboratory (LLNL). For larger events, Mw’s calculated using Moment Tensor Inversion (MTI) and use as reference events in CCT. Initial results show good agreement with MTI Mw’s for larger events (Mw>5.3). An orthogonal regression analysis is performed between Mw and ML magnitudes which can then be used to convert local magnitudes into Mw at the Georgian National Seismic Data Center.

Presenting Author: Tea Godoladze

Authors