5:15 PM - 6:30 PM
[SSS05-P07] Evaluation earthquake potential using a kinematic block motion model in Indonesia based on GNSS Observation
Indonesia is located in a tectonically complex region and lies in the interaction of four major plates. This interaction resulted in seismic activity in Indonesia and is one of the highest in the world. With this condition, research on evaluating the earthquake potential in Indonesia becomes urgent. Previous geology and geodesy studies have been done to describe the crustal block boundaries and also crustal block motion in Indonesia (e.g. Bird, 2003; Koulali et al., 2016; Koulali et al., 2017). However, some inland faults are still not well described, and used few GNSS data in previous studies. This research would provide an improved crustal block motion model for Indonesia to evaluate the interaction among these blocks and estimate the earthquake potential in research area and also to identify which regions are more vulnerable to the earthquake.
In this research, we use GNSS data derived from Indonesia CORS Network (InaCORS), Sumatran GPS Array (SuGAR), and International GNSS Service (IGS). The total number of GNSS sites is 205 during 2008 to 2018. To get the velocity field, we utilize Bernese 5.2 software package (Dach et al., 2015) and VISCO1D (Pollitz et al, 1997) for analyzing the GNSS data and removing the deformation due to earthquakes that occurred before 2008, respectively. We employ the MCMC (Markov Chain Monte Carlo) method to generate many kinematic block motion models and choose the optimum model based on AIC (Akaike’s Information Criterion).
By using the optimum model, MODEL12, our results of coupling show that the strong coupling is estimated mostly at the depth of 0-30km and mostly weak coupling for more than lower than 30km depth. Our results also show a possible recovery from the 2006 Java earthquake. For the earthquake potential, our results show 4 areas with high coupling which possible to generate big earthquakes. Area 1 has enough seismic moment deficit to produce a Mw8.3 earthquake every 119±15 years. Area 2, Area 3, and Area 4 have enough seismic moment deficit to produce a Mw8.6 earthquake every 182±24 years, 186±27 years, and 169±24 years, respectively. A Mw8.9 earthquake can be produced every 261±35 years if Area 2 and Area 3 rupture together at the same time.
In this research, we use GNSS data derived from Indonesia CORS Network (InaCORS), Sumatran GPS Array (SuGAR), and International GNSS Service (IGS). The total number of GNSS sites is 205 during 2008 to 2018. To get the velocity field, we utilize Bernese 5.2 software package (Dach et al., 2015) and VISCO1D (Pollitz et al, 1997) for analyzing the GNSS data and removing the deformation due to earthquakes that occurred before 2008, respectively. We employ the MCMC (Markov Chain Monte Carlo) method to generate many kinematic block motion models and choose the optimum model based on AIC (Akaike’s Information Criterion).
By using the optimum model, MODEL12, our results of coupling show that the strong coupling is estimated mostly at the depth of 0-30km and mostly weak coupling for more than lower than 30km depth. Our results also show a possible recovery from the 2006 Java earthquake. For the earthquake potential, our results show 4 areas with high coupling which possible to generate big earthquakes. Area 1 has enough seismic moment deficit to produce a Mw8.3 earthquake every 119±15 years. Area 2, Area 3, and Area 4 have enough seismic moment deficit to produce a Mw8.6 earthquake every 182±24 years, 186±27 years, and 169±24 years, respectively. A Mw8.9 earthquake can be produced every 261±35 years if Area 2 and Area 3 rupture together at the same time.