The 26 September 2019 Mw 6.5 Ambon earthquake has been the largest instrumentally recorded event to occur in Ambon, the capital city of Maluku Islands, eastern Indonesia, and ruptured a previously unmapped active fault. In this study, we use seismic and geodetic data to investigate the source characteristics of the event. Our results show that the rupture process was complex in both the rupture initiation and slip directions. In addition, the rupture was mostly strike-slip motion with normal component and pure reverse slip in the north of the inverted fault. Our analysis of campaign and continuous Global Positioning System (GPS) velocity fields estimates that the fault has a 4.9 [4.0, 5.5] mm/yr slip rate with an earthquake recurrence interval of 115 [102, 141] yr. In addition, a comparison of the horizontal strain-rate tensor derived from GPS velocity fields with historical earthquake data shows that Ambon Island and the nearby regions have a high strain accumulation rate correlated with the distribution of Mw≥6 earthquakes, indicating that the regions are seismically active and possibly will experience more Ambon-type earthquakes in the future.
On September 12, 2007, a M8.5 megathrust earthquake occurred along the Sunda trench near Bengkulu, West Sumatra. GPS data in Sumatra have indicated the coseismic and postseismic deformations resulting from this earthquake. Our estimate of coseismic displacements suggests that the earthquake displaced up to ~1.8m at GPS stations located north of the epicenter. Moreover, our principal strain estimation in the region suggests that the maximum coseismic extensional strain is ~40 ppm. Our analysis of GPS data in the region suggests that the postseismic decay of the 2007 Bengkulu earthquake was 46 days, estimated using a logarithmic function.
Banda arc is a product of complex interactions between the Eurasian, Australian, Pacific and Philippine Sea plates. As a result of this tectonic interaction, the Banda arc has undergone significant deformation of the crust, both in the horizontal and vertical directions. In this study, we performed a time-series data analysis of displacement in vertical components. A total of 16 permanents GPS observations from 2008 to 2013 were collected and analysed in this study. The GPS sites spread around the Banda arc area from Bali island in the south to Ambon in the north. This is the first research on vertical deformation analysis carried out in this area. The results of this study show that 3 GPS sites experience a subsidence, which are BANI, CAMB and CTOA, while the 13 others experience an uplift mechanism. The spatial pattern of vertical deformation obtained from this research will provide insight about tectonic conditions and can then be used as a basis for conducting seismic hazard analysis in the Banda arc.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.