Abstract by Rachel Willmore
Seismic gap along Java Trench, Indonesia and implications for a 9.0 magnitude earthquake
Indonesia is located at a tectonically active and complicated subduction zone. Earthquakes and tsunamis threaten most of the 200 million people who live there. Based on the frequency and locality of subduction zone earthquakes, seismic gaps can be located, allowing us to predict where future earthquakes may occur and the associated hazards. The Java trench is one such seismic gap. Located just south of the island of Java, it experiences about 70 mm/year of tectonic loading. Medium-sized earthquakes that have released a few percent of the loading are recorded instrumentally and in historical account, but there is no evidence of a mega-thrust event during the past 440 years of historical records. Tsunami deposits indicate megathrust earthquakes have struck in the recent past. In the years since the last megathrust event there has been about 31 m of tectonic loading on the subduction interface. The sudden release over the entire length of the Java Trench of this accumulated load will produce an earthquake around magnitude 9.0.