INTERPLATE COUPLING OFF THE SOUTH OF JAVA ISLAND BASED ON GPS OBSERVATION IN 2010-2018

• Main Author: Hairani Fitri, Intan
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/47275
• Institution: Institut Teknologi Bandung

Previous studies (Simons et al. 2007, Bock et al. 2003) suggest that Java Trench is weakly coupled and could be deforming aseismically, since subduction of older seafloor tends to take place aseismically (Newcomb and McCann, 1987). However, seismic records show that most of the devastating earthquakes with magnitude over 7 on Java Island were associated with the subduction zone located in the southern part of Java (Newcomb and McCann, 1987). Therefore, using 9 years of continuous GPS data on Java, the surface displacement is calculated to model slip distribution on the plate interface using an inversion method namely ABIC (Akaike Bayesian Information Criterion) Inversion (Yabuki and Matsu?ura, 1992). Slip deficit / excess distribution in southern part of east and west Java shows a huge patch of slip deficit, indicating the occurrence of fault locking. The maximum coupling ratio is 32% in east Java, and 26% in the west. Meanwhile, slip deficit / excess distribution in southern part of central Java shows a huge patch of slip excess, indicating the occurrence of slipping faster than the convergence rate. This could be the effect of ongoing postseismic deformation from M7.7 Pangandaran earthquake in 2006.