The coulomb stress changes for correlation analysis of tectonic earthquake activity and volcanic of the 2001–2010 Merapi eruption based on focal mechanism data

The incident of increased seismic activity of the Merapi volcano was initiated by several tectonic earthquake
phenomena. Analysis of the mechanism of tectonic earthquakes can be studied based on the combination of static
stress on the rock. This paper describes the distribution of the Coulomb stress changes due to the interaction that
occurs in tectonic earthquakes with volcanic activity. The data in the calculation of the Coulomb stress distribution
are secondary in the form of tectonic seismicity data downloaded from the ISC (International Seismological
Center), USGS (United States Geological Survey), and Global CMT (Global Centroid Moment Tensor) catalogs
between 2001 and 2010. Calculation results and data analysis is the occurrence of an increase in Coulomb stress
response in the Merapi Volcano area with a value range of 0.2–10 kPa at a depth of 2–4 km below the peak of
Merapi Volcano. The Coulomb stress changes distribution is thought to indicate the accumulation of stress due to
tectonic earthquakes that downward at the top of the volcano, thereby affecting the stability of the magma
chamber and causing volcanic activity at the Merapi volcano.