Published
20 July 2017 Bodrum-Kos Earthquake (Mw:6.6) in southwestern Anatolia, Turkey
Terremoto de magnitud 6.6 en Bodrum-Kos, el 20 de julio de 2017, en el suroeste de Anatolia, Turquía
DOI:
https://doi.org/10.15446/esrj.v25n3.87080Keywords:
Bodrum, Kos, Earthquake, Normal Fault, Inversion, Extension (en)Bodrum; Kos; Terremoto; Falla normal; Inversión; Extensión (es)
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In the Aegean Sea, the western part of Gökova Gulf, Kos and Bodrum were struck by a 6.6 (Mw) earthquake on July 20, 2017. The fault plane solution for the main shock shows an E-W striking normal type fault with approximately N-S (N4°E) tensional axis (T-axis). Fault plane solutions of 33 aftershocks show two groups of normal type fault with E-W and NE-SW to ENE-WSW orientations. The inversion of the focal mechanisms of the aftershocks yields two different normal faulting stress regimes: one is characterized by an approximately N-S (N5°E) σ3 axis (minimum horizontal stress axis). This extension is obtained from 13 focal mechanisms of aftershocks with approximately E-W direction. The other is characterized by approximately NW-SE (N330°E) σ3 axis. The latter is calculated from 21 seismic faults of aftershocks with approximately NE-SW direction. These aftershocks occurred on relatively small-scale faults that were directed from NE-SW to ENE-WSW, and possibly contributed to expansion of the basin in the west. The 24 focal mechanisms of earthquakes which occurred since 1933 in and around Gökova Basin are introduced into the inversion analysis to obtain the stress state effective in a wider region. The inversion yields an extensional stress regime characterized by an approximately N-S (N355°E) σ3 axis. The E-W directional metric faults, measured in the central part of Gökova Fault Zone bordering the Gökova Gulf in the north, also indicate N-S extension. The NE-SW extension obtained from NE-SW aftershocks appears to be more local and is responsible for the expansion of the western part of the asymmetric Gökova Basin. This N-S extension which appears to act on a regional-scale may be attributed to the geodynamic effects related to the combined forces of the southwestward extrusion of Anatolia and the roll-back process of African subduction beneath Anatolia.
A 6.6 (Mw) earthquake struck the western part of Gökova Gulf in the eastern Aegean Sea on July 20, 2017. The fault plane solution for the mainshock shows an E-W striking normal fault with approximately N-S (N4°E) tensional axis (T-axis). Fault plane solutions for 33 aftershocks offer two groups of normal faulting with E-W and NE-SW to ENE-WSW orientations. The inversion of the focal mechanisms of the aftershocks yields two different extensional stress regimes. The stress regime obtained from 12 focal mechanisms of aftershocks and the mainshock is characterized by an approximately N-S (N5°E) σ3 axis, while the other regime calculated from 21 focal mechanisms of aftershocks exhibits σ3 axis in an NW-SE (N330°E) direction. The latter extension significantly affects the basin's growth in the area where the earthquake occurred. Twenty-four focal mechanisms of earthquakes in and around Gökova Basin before the 2017 earthquake (1933-2017) were included in the inversion to determine the stress state effective in a larger area. The inversion yielded an extensional stress regime characterized by approximately N-S (N356°E) σ3 axis. E-W trending faults inferred in the central part of Gökova Fault Zone, bordering Gökova Gulf in the north, also indicate N-S extension. The NW-SE extension obtained from NE-SW aftershocks appears to be locally effective in the northwest of Gökova Gulf. N-S extension, which appears to act on a regional scale, may be attributed to geodynamic effects related to the roll-back of the African subduction beneath the Aegean.
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