Double-difference earthquake relocation using waveform cross-correlation in Central and East Java, Indonesia

Abstract The Central and East Java region, which is part of the Sunda Arc, has relatively high seismic rates due to convergence two major tectonic plates in Indonesian region; i.e., Indo-Australian Plate subducting under Eurasian Plate. Many devastating earthquakes have occurred this area as a result interaction between these plates. Two examples are 1994 Banyuwangi earthquake (Mw 7.6) 2006 Yogyakarta 6.3). This study aims determine precise locations analyze pattern distribution Java, Indonesia. We manually re-picked P S-wave arrival times that were recorded by Agency for Meteorology, Climatology Geophysics (BMKG) network during time period January 2009–September 2017. then determined using non-linear method. To improve accuracy locations, we relocated 1,127 out 1,529 events, double-difference algorithm with waveform cross-correlation data. Overall, seismicity region predominantly distributed south Island; e.g., Kebumen, Yogyakarta, Pacitan, Malang, clusters. These clusters probably related subduction activity regions. Meanwhile, there having shallow depths on mainland indicate inland faults Opak Fault, Kendeng Thrust, Rembang–Madura–Kangean–Sakala (RMKS) Fault Zone. Several other active not shown any significant over mentioned, Pasuruan Lasem Muria Semarang Probolinggo Fault.