Coulomb Stress Analysis And Monte Carlo Simulation In Predicting Sinabung Pyroclastic Flow

Abstract

Sinabung is a small stratovolcano located in northern Sumatra about 50 km northwest of the Toba caldera. On August 27, 2010, it was confirmed that Sinabung experienced a phreatic eruption for the first time in history. Initially the eruption formed a lava dome that fell out on January 10, 2014 forming pyroclastic density currents. An increase in pore fluid pressure in the crust supports Coulomb Failure Friction. Positive coulomb stress values ​​are thought to trigger Sinabung activity. The research uses a combination of Monte Carlo simulation to predict the next earthquake parameters and coulomb stress analysis to determine the direction and value of stress . The Monte Carlo simulation produces earthquake parameter prediction, longitude 98o latitude 3.175o depth 104.5 meters, Mw 6.0, strike 28.125 o, slip 42o, dip 44.17o. Coulomb Stress analysis of the combined 2001-2021 earthquake data produces an average coulomb value of 0.24 bar, 0.14 bar shear, 0.25 bar normal and the direction of the stress vector to the southwest of Mount Sinabung. The results of the combined coulomb stress analysis and Monte Carlo simulation predict the direction of pyroclastic flows to the northeast, east, and southeast of Mount Sinabung, in accordance with the direction that is inversely proportional to positive stress so that the area needs to receive early warning of volcanic eruption natural disasters in 2022.