A study of earthquake potential analysis in central java and Yogyakarta provinces, Indonesia based on the calculation of a and B-Values with the maximum likelihood method

• Published in: ARPN journal of engineering and applied sciences 2023-09, p.2147-2150
• Format: Article
• Language: English
• ISSN: 2409-5656; 1819-6608
• DOI: 10.59018/0923263

There are several active faults in Central Java and Yogyakarta (Indonesia), such as the Opak Fault, Baribis- Kendeng Fault, Merapi-Merbabu Fault, and others. In addition, Central Java and Yogyakarta are located near the subduction zone in the south of Java Island due to the collision of the Eurasian Plate and the Indo-Australian Plate. This has contributed to the fact that earthquakes can occur in Central Java and Yogyakarta. The purpose of this research is analyze the earthquake potential in Central Java, which includes an analysis of the a-value (seismicity level) and b-value (regional stress level) as an earthquake hazard mitigation effort. The Gutenberg-Richter equation expresses the relationship between earthquake frequency and magnitude as a straight-line equation containing the a-value and b-value parameters. The calculation of the b-value of the Gutenberg-Richter equation can be conducted with a modification of the maximum likelihood method. From 122 main earthquake events in the IRIS catalog, the values for depth (0-33) km are b = 1.01 ± 0.01 and a = 6.31, for depth (0-10) km, b = 1.44 ± 0.2 and a = 7.58; while for depth (10-33) km, b = 0.91 ± 0.1 and a = 5.73. The depth of (0-33) km and the depth of (0-10) km shows high a-value and b-value, while the depth of (10-33) km shows low a-value and b-value.