Project Details
Projekt
Earthquake source characterization and directivity effects near Istanbul: Implications for seismic hazard
Applicant
Dr. Patricia Martinez-Garzon
Subject Area
Geophysics
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 457735407
The goal of this proposal is to investigate the source properties and directivity effects of small to moderate magnitude (M 4.5) earthquakes in the eastern Sea of Marmara region and relatively benchmark them with analogous results from similar tectonic setting in southern California where a denser seismic network is available. The calculated source parameters at the eastern Sea of Marmara and the compiled source parameters from existing studies in southern California will be used to:(1) Investigate the consistency of source properties and directivity effects within specific regions with mechanical models of dynamic rupture on a velocity contrast (bimaterial) interface. (2) Relate the obtained source parameters and directivity effects with the distribution of ground motion, thus constraining seismic shaking hazard at nearby population centers.(3) Decipher whether the rupture directivity of small to moderate earthquakes is consistent with that of the large events in the same region.Analysis of earthquake source properties provide fundamental information on physics of earthquake processes, and can contribute to the understanding of seismic ground motions. Source properties and particularly directivity effects are not yet systematically addressed for moderate to lower magnitudes because of their higher frequencies and weaker signal involved as well as the necessity of having an optimal monitoring seismic network. Nevertheless, several studies shown that M<4.5 events on given fault sections have clear preferred rupture direction generally consistent with theoretical expectations for bimaterial ruptures in strike-slip faults. Resolving directivity of well recorded moderate and small magnitude events (more frequent) across sections of strike slip faults near highly populated regions can significantly contribute to identifying regions of increased ground motions and site effects.This project aims at addressing the objectives mentioned above through analysis of source properties and directivity effects of earthquakes from the eastern Sea of Marmara and their correlation with a) results from seismic velocity tomography, and b) ground motion variability. Research on the proposed topics is particularly relevant for fault zones located near populated areas. Thus, I propose the eastern Sea of Marmara region in north-western Turkey as the main study area, in direct vicinity of the Istanbul metropolitan region with its >15 million inhabitants. At this location, high-resolution geophysical data from the permanent ICDP-GONAF observatory is being collected. The outcome of this proposal using ICDP-GONAF instrumentation will contribute to predict the orientation of propagation of earthquakes in the selected region and improving the understanding of the relation between earthquake source properties and seismic hazard and risk.
DFG Programme
Infrastructure Priority Programmes
International Connection
USA
Co-Investigators
Professor Dr. Marco Bohnhoff; Professor Dr. Fabrice Cotton; Professor Dr. Georg Dresen; Professorin Rebecca Harrington, Ph.D.; Grzegorz Kwiatek, Ph.D.
Cooperation Partner
Professor Dr. Yehuda Ben Zion
