Identifying Intraplate Mechanism by B-Value Calculations in the South of Java Island

41st HAGI Annual Convention and Exhibition 2016

Ida Bagus Suananda, Y.^1 ; Aufa, Irfan^1 ; Harlianti, Ulvienin^1

Geophysical Engineering, Bandung Institute of Technology, Indonesia^1

关键词: B value;    Earthquake data;    Earthquake disaster;    Eurasia plate;    Indonesia;    Interplate earthquakes;    Intraplate earthquakes;    Oceanic crust;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/132/1/012032/pdf
DOI  :  10.1088/1755-1315/132/1/012032

来源: IOP

【 摘 要 】

Java is the most populous island in Indonesia with 50 million people live there. This island geologically formed at the Eurasia plate margin by the subduction of the Australian oceanic crust. At the south part of Java, beside the occurrence of 2-plate convergence earthquake (interplate), there are also the activities of the intraplate earthquake. Research for distinguish this 2 different earthquake type is necessary for estimating the behavior of the earthquake that may occur. The aim of this research is to map the b-value in the south of Java using earthquake data from 1963 until 2008. The research area are divided into clusters based on the epicenter mapping results with magnitude more than 4 and three different depth (0-30 km, 30-60 km, 60-100 km). This location clustering indicate group of earthquakes occurred by the same structure or mechanism. On some cluster in the south of Java, b-value obtained are between 0.8 and 1.25. This range of b-value indicates the region was intraplate earthquake zone, with 0.72-1.2 b-value range is the indication of intraplate earthquake zone. The final validation is to determine the mechanism of a segment done by correlating the epicenter and b-value plot with the available structural geology data. Based on this research, we discover that the earthquakes occur in Java not only the interplate earthquake, the intraplate earthquake also occurred here. By identifying the mechanism of a segment in the south of Java, earthquake characterization that may occur can be done for developing the accurate earthquake disaster mitigation system.