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National Seismic Hazard Assessment for Azerbaijan Using New Seismic Data and Ground Motion Simulations

Description: 

A new probabilistic seismic hazard assessment (PSHA) was carried out in Azerbaijan under the Seismic Cooperation Program at the Lawrence Livermore National Laboratory. The study started with a Caucasus-wide compilation of an earthquake database. Next, Mw was calculated for about 400 earthquakes using Coda Calibration Technique. Azerbaijan had many stations where modern digital seismometers were co-located with Soviet-era equipment, which was instrumental in developing magnitude conversion relations between Mw and Soviet era magnitude scales. Following magnitude harmonization, catalogue completeness intervals were computed. In addition, earthquake relocation was carried out providing more accurate locations and depths for earthquakes, better delineating a subduction structure that have been the subject of past investigations. Two versions of the PSHA-ready catalogue were generated, one with declustering applied and one without. Known active faults with geologic slip rates in this region are sparse, but a few were identified in neighbouring countries that might impact Azerbaijan. A source model was put together using both the seismic activity rates based on the earthquake catalogue and the identified active faults. Azerbaijan has a strong motion network that has about 40 accelerometers. Contemporary ground motion models (GMMs) from US, Japan, Europe and Middle East were tested against recorded data, which showed that the ground motion attenuation in much of Azerbaijan is generally slower than active tectonic regions like California, but faster than stable continental regions like Eastern North America. The difference also varies by frequency/period of vibration. The reason for the difference appears to be not tectonic in origin but rather due to thick sedimentary layers in the Kura basin. In order to quantify these effects, we perform 3-D hybrid ground motion simulations to inform the selection of the GMMs and the weights to use in the PSHA. We present preliminary results that have been well-received by the engineering community in Azerbaijan and are currently being considered for use in the building code update.

Session: Regional-Scale Hazard, Risk and Loss Assessments [Poster Session]

Type: Poster

Date: 5/3/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Tuna

Student Presenter: No

Invited Presentation: 

Authors