[SSS08-P02] Microseismicity distribution and inferred fault geometry beneath the western Marmara Sea, Turkey, deduced from long-term ocean bottom seismographic observations
Keywords:The North Anatolian Fault, Marmara Sea, Seismicity, Fault geometry
The result shows that the feature of hypocenter distribution, including the location of no seismicity zones obtained by Yamamoto et al. (2017), is not changed, suggesting that the coupling status along the fault is almost same during at least two years. The largest no seismicity zone extended over the upper crust is located between 28.45°E and 28.65°E, where strong coupling is suggested from seafloor geodetic observation (Lange et al., 2019; Sakic et al., 2016). By combining the relocation result of first and second phases, the detailed fault geometries were clarified. Beneath the Western High and western Central Basin (27.75~28.05°E), we found two branch faults whose dip angles are gentler (30~60) than that of MMF (almost vertical). The cross point of two branch faults and MMF locates about 15 km depth of MMF. Although these faults might relate to the pull-apart or negative flower structure around the Central Basin, we could not find similar structure in eastern Central Basin.