[Proceeding] – Spatial and Temporal b-value Variable Analysis: Mapping Earthquake-Prone Area in Indonesian Triple junction Zone

Penulis: Andi Mardhotilla, Adelia Suryani, and Muh. Iqbal Sulaiman

North West Papua Indonesia places in one unique region that has complex tectonic setting where three plates collide, intersect each other and create a triple junction situation. The three plates are Indo-Australia plate, Eurasia plate, and Pacific plate. Based on USGS (United States Geology Survey) and ISC (International Seismological Centre) catalogue data from 1978 until 2018, about four thousand earthquakes occurred on this triple junction region. We collected events on this region with magnitude ranging from 4.0 until 7.0 with magnitude type is Mb and depth less than 70 km. After that we represent the b-value analysis using Gutenberg-Richter equation to understand more about the event’s characteristic on triple junction area. B-value itself reflects the activity of local stress, that the higher the value means how likely one region possibility to create small or big earthquake. In several stress field area such as subduction zone statistically significant b-value change. Final results show that the center of triple junction has high b value at about 0,9 close to global b value number at 1 and show the area is not dominated by high magnitude number only. However temporal b value analysis on our dataset do not generate strong evidence that a big event can be estimated by analyzing b value or a trend of b value.

Download: https://doi.org/10.1190/SEGJ2018-122.1