The 20 July 2017 Bodrum-Kos Earthquake in southwestern Anatolia, Turkey/Terremoto de magnitud 6.6 en Bodrum-Kos, el 20 de julio de 2017, en el suroeste de Anatolia, Turquia

• Published in: Earth sciences research journal 2021-09, Vol.25 (3), p.309
• Main Authors: Over, Semir, Ozden, Suha, Ertan, Esra Kalkan, Turhan, Fatih, Coskun, Zeynep, Pinar, Ali
• Format: Article
• Language: English
• Subjects: Aegean Sea; Africa; Earthquakes; Seismology
• ISSN: 1794-6190
• DOI: 10.15446/esri.v25n3.87080

A 6.6 (Mw) earthquake struck the western part of Gokova 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[degrees]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[degrees]E) G3 axis, while the other regime calculated from 21 focal mechanisms of aftershocks exhibits G3 axis in an NW-SE (N330[degrees]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 Gokova 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[degrees]E) G3 axis. E-W trending faults inferred in the central part of Gokova Fault Zone, bordering Gokova 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 Gokova 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. Keywords: Bodrum; Kos; Earthquake; Normal Fault; Inversion; Extension Un terremoto de magnitud 6.6 golpeo la parte oeste del golfo de Gokova en el este del mar Egeo el 20 de julio de 2017. El mecanismo focal del evento principal muestra un movimiento E-O en la falla normal con un eje tensional (T-axis, en ingles) en direction N-S (N4[degrees]E). El mecanismo focal de 33 replicas muestra dos grupos de fallamiento normal con orientaciones E-O y NE-SO hacia ENE-OSO. La inversion del mecanismo focal de las replicas produjo dos regimenes de fuerza extensiva diferentes. El regimen de fuerza obtenido a traves de 12 mecanismos focales de replicas y del movimiento principal se caracteriza por un desplazamiento aproximado N-S (N5[degrees]E) [sigma]3 del eje, mientras que el otro regimen se calculo a partir de 21 mecanismos focales en replicas y muestra un desplazamiento del ej e en direction NO-SE (N330[de