Preliminary Results: P-wave Seismic Tomography Beneath of Java Subduction Zone, Indonesia
Mia Uswatun Hasanah, Sinta Caenur Winusda, Deanne Ardelia Zahrani, Difa Mutafawwiqoh, Arya Samudera

Geophysical Department, Faculty of Math and Science, Universitas Padjadjaran, Sumedang 45361, Indonesia.

Abstract

Java Island, a volcanic island in Indonesia, is shaped by the movement of tectonic plates beneath it. The complex process of subduction beneath Java Island, involving the Indo-Australian Plate being forced beneath the Eurasian Plate, results in frequent volcanic eruptions and earthquakes. This movement creates immense pressure and friction, leading to seismic activity. The history of past earthquakes and tsunamis near Java Island serves as a reminder of the devastating potential of tectonic activity in the region. The people of Java are accustomed to living with the constant threat of volcanic eruptions and earthquakes, but also appreciate the beauty and resources it brings. Efforts to monitor and predict potential seismic events are being made to improve disaster preparedness in Java and surrounding regions. This study uses ISC-EHB catalogue data recorded in the 1964-2018 period which has 28,545 earthquake events recorded by 512 earthquake recording stations consisting of 590,880 phase P. Resolution testing with various speed grids shows that the resolution is medium with a size of 100 km x 100 km x 100 km provides the most optimal results in the inversion process. The tomographic inversion results provide a good overview of the subsurface structures in the Earth^s crust and mantle to a depth of 450 km below the Java. There is a high velocity anomaly up to a depth of 300 km which is possibly related to the subduction of the Java More detailed subsurface information from this research can be used as input for mapping disaster-prone areas to help support disaster mitigation in the area.

Keywords: Java, Tomography, ISC-EHB data.

Topic: Earth Physics and Space Science