Search

Ambon earthquake (Mw 6.5) occurred on September 26, 2019, has an almost identical location with the earthquake which occurred on September 09, 1932. Accordingly, the authors considered that the return period (Tr) of the earthquake takes 87 years. Along the interseismic period, there were stress accumulation processes related to the earthquake (Mw 6.5). Based on the passing through of scaling law relation of the earthquake, the authors calculated the fault length (L), fault width (W), and displacement rate (d), as well as the seismic moment (M0), are about 19 km, 15 km, 46-47 cm, and 6.185x1025 dyne-cm, respectively. By using the values off M0, L, W, and Tr, the authors have estimated other parameters, such as the static stress drop (9.21 bars), slip rate (8-9 mm/y), strain rate 6x10-15/s, and static stress Coulomb (more than 1 Pa). Two earthquakes that triggered the tsunami occurred on January 29, 2004 (Mw 6.7) and March 14, 2006 (Mw 6.7) in a similar tectonic regime and adjacent to the Ambon earthquake occurred on September 26, 2019. By using a passing through physical basic approach, the authors have estimated the return period (Tr) of both earthquakes (i.e. about 93 years and 113 years), respectively. [ABSTRACT FROM AUTHOR]

We have conducted geoelectric resistivity and shear wave velocity (Vs30) study to identify the landslide potential hazard, around Geophysics Station Lembang, Bandung (107,617∘ E and 6,825∘ S). The the geoelectric analysis using Dipole-Dipole resitivity configuration, while shear wave velocity analysis performed using the Multichannel Analysis of Surface Wave (MASW). The study results indicate that the assumed soil or clay depth from the electrical resistivity observation was in accordance with the confirmed soil or clay depth by the MASW investigation. Based on these conditions, indicate the high potential of landsliding in this area, landslide potential supported by high slope angle in this area. [ABSTRACT FROM AUTHOR]

Subduction zone along west of Sumatra and Sumatran fault zone are active seismic sources. Seismotectonically, South Sumatra could be affected by earthquakes triggered by these seismic sources. This paper discussed contribution of each seismic source to earthquake hazards for cities of Palembang, Prabumulih, Banyuasin, OganIlir, Ogan Komering Ilir, South Oku, Musi Rawas and Empat Lawang. These hazards are presented in form of seismic hazard curves. The study was conducted by using Probabilistic Seismic Hazard Anal ysis (PSHA) of 2% probability of exceedance in 50 years. Seismic sources used in analysis included megathrust zone M2 of Sumatra and South Sumatra, background seismic sources and shallow crustal seismic sources consist of Ketaun, Musi, Manna and Kumering faults. The results of the study showed that for cities relatively far from the seismic sources, subduction / megathrust seismic source with a depth ≤ 50 km greatly contributed to the seismic hazard and the other areas showed deep background seismic sources with a depth of more than 100 km dominate to seismic hazard respectively. [ABSTRACT FROM AUTHOR]