FOCAL MECHANISM ANALYSIS ON MICROEARTHQUAKES IN “AAA” GEOTHERMAL FIELD IN FEBRUARY – MAY 2016 PERIOD WITH MOMENT TENSOR INVERSION

• Main Author: Afif Alfaro Adiyoso, Muhammad
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/36192
• Institution: Institut Teknologi Bandung

The "AAA" Geothermal Field is one of the geothermal fields that is actively operating on Java Island which is located on the Southern Java Mountain Range which is the result of subduction between the Indian-Australian Plate and the Eurasian Plate which began in tertiary times. In a Geothermal Field, research on the focus mechanism is one of the best approaches to determine the causes of micro-earthquakes and their relation between current reservoir conditions and a decrease in production due to exploitation where a combination of micro-earthquake mechanisms with accurate fault orientation information can produce detailed information about the subsurface geological structure due to triggered such as fluid activity. To identify detailed source mechanisms from the "AAA" Geothermal Field area, we can identify the focus mechanism of events that occur around the "AAA" Geothermal Field location from the period February - May 2016 using the moment tensor inversion method. Determination of the initial hypocenter location is carried out using the Geiger method. Then hypocenter relocation was performed using the Double-Difference method, and the focus mechanism was determined using the moment tensor inversion method. The moment tensor inversion results are dominated by the source mechanism in the form of sinistral strike slip in the southern cluster zone and in the form of a CLVD in the northern cluster zone that occurs due to geothermal fluid activity associated with the presence of a subsurface reservoir.