Turkish Journal of Earth Sciences
Abstract
The Germencik geothermal field with 240 °C fluid temperature is one of the most important energy production areas located at the westernmost end of the Büyük Menderes Graben (western Türkiye). The northern boundary faults of the graben have a dip angle larger than 50° and have listric characteristics. In this brief study, the earthquake activity between 2007 - 2024 in the Germencik geothermal field is improved with the double-difference inversion method to image the deep normal fault planes down to 20 km of the crust. Considering the steeply southward dipping boundary faults in the graben, probable listric normal faults in the upper crust are demonstrated with earthquake hypocenters for the first time. The deep image of the listric faults indicates that these are the main carriers for the upwelling hot geothermal fluid, which are schematically shown in the conceptual geothermal models of Germencik. On the other hand, a significant microearthquake activity was observed in 2009, when the energy production of the Germencik was starting. The slope of the Gutenberg-Richter relation of the activity between 2007 and 2011 (b-value = 1.55) is higher than the tectonically normal value of 1.0 and may be related to the initiation of geothermal operations. However, the seismological data of the national network after 2011 do not show any evident relation between moderate/large earthquake occurrence and geothermal operation activity in Germencik.
Author ORCID Identifier
ONUR TAN: 0000-0002-5395-8349
DOI
10.55730/1300-0985.1946
Keywords
Earthquakes, Germencik, geothermal, listric normal fault
First Page
68
Last Page
77
Publisher
The Scientific and Technological Research Council of Türkiye (TÜBİTAK)
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
TAN, ONUR
(2025)
"Imaging fault geometries in the upper crust using high-resolution earthquakehypocenters in the Germencik geothermal field, western Türkiye,"
Turkish Journal of Earth Sciences: Vol. 34:
No.
1, Article 5.
https://doi.org/10.55730/1300-0985.1946
Available at:
https://journals.tubitak.gov.tr/earth/vol34/iss1/5