M.S. Syirojudin1 , M. Masturyono1 , J.M. Murjaya1 , S.A. Ahadi1 , A.Y. Yoshikawa2
1Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG), National Seismological Center, Jakarta, Indonesia
2International Center for Space Weather Science and Education (ICSWSE), Kyushu University, Kyushu, Japan
Although earthquake prediction is still controversial for seismologists, there has been significant progress in the detection of earthquake precursors using geomagnetic data. We developed the Earthquake Precursor Monitoring System (EPMS) based on the geomagnetic data recorded in the Geomagnetic Stations located in Sumatera. The seismomagnetic anomaly is calculated and analyzed weekly using the power spectral ratio method of the Ultra Low Frequency (ULF) signal. The Anomaly is used to estimate the magnitude and lead time of the coming potential earthquake, while the azimuthal coverage of the anomaly sources are used to determine the direction and distance of the earthquake. By running EPMS for about three years, we found that the systems are able to predict earthquakes with Magnitude > 5 from 2014 that have occurred at Sumatera region. The occurrence of the predicted earthquakes are in the range of 3-24 days after the geomagnetic precursor detected and the location of the earthquakes are within the cross-section area of the azimuthal coverage between two or more stations. By using the result of 20 predicted earthquakes we find an empirical formula to estimate the magnitude as M=0.088*Amp+0.002*distance+4.334. This result has the possibility to improve monitoring of the precursor of large earthquake.