Geodetic and Seismological Investigations of Crustal Deformation around Izmir (Western Turkey) Using GPS Observations and Earthquake Seismicity Parameters
Abstract
The Aegean Region including Western part of Turkey, mainland of Greece, the Hellenic Arc is the most active domain and deforming part in terms of seismological and geodynamical structure, which is placed in the Alpine Himalayan Belt. In this study, we processed 3 years of survey-mode GPS data and present the analysis of a combination of geodetic and seismological data around Izmir, which is the third most crowded city in Turkey. The obtained velocities from15 sites vary between 25 mm/yr and 28.5 mm/yr with respect to Eurasia plate. The b-value ranges from 0.7 to 1.7 along Izmir region between 26.0°E and 27.5°E. The lowest b-value zones (~0.7) are found along Gulbahce-Karaburun, Izmir and Kemalpasa Faults. A localized stress concentration is expected from numerical models of seismicity along geometrical asperities. Therefore, areas with lowest b-values are considered to be most likely location for a strong earthquake, a conclusion that is confirmed by the 2005 Mw=5.9 Seferihisar earthquake sequences, with epicentres located near the Gulbahce-Karaburun Fault zone. The extensional nature of Izmir area is corroborated by extension rates upto 200 nanostrain/yr as obtained from 3 years of GPS data. Our conclusions derived from the processing and analysis of the GPS data can be justified by the seismicity. We propose that the strong differences in b-value observed along the complex fault can be used to identify different states of tectonic deformation in space and time.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.G53A1116G
- Keywords:
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- 1209 GEODESY AND GRAVITY / Tectonic deformation;
- 7230 SEISMOLOGY / Seismicity and tectonics;
- 4302 NATURAL HAZARDS / Geological