Seismotectonic Studies to Determine the Recurrence of Earthquakes Mw > 7 Using a Statistical Approach and Plate Motion in the Megathrust Western Part of Java

We propose calculating the earthquake return period based on statistical approaches and the properties of plate convergence at Java Trench. The tectonic characteristic can be known from the b-value and the number of earthquakes is represented by the a-value found in the Gutenberg-Richter law. The return period is calculated base on a statistical approach using Gutenberg-Richter law and the vector slip value of a major earthquake targeted divided by the average plate velocity at the source. The recurrence and the probability of an earthquake happening are using the Wibul method. The result was found, that the southern Middle Java has a recurrence of Mw > 7, which is relatively faster than other areas around the western part of Java. Quiescence in the megathrust south of West Java has the potential for a large earthquake, indicated by a seismic gap. We use Wibul method to calculate the recurrence of the earthquake Mw > 7 and get the result of 500 years with a probability of 99% in megathrust. We find the location of the seismic gaps on the contact area of the convergent plates at a depth of 10–25 km. The location of seismic gaps is correlated with a low b-value, which has the potential to produce large earthquakes in the future.