F.R. Priyambada¹ , M. Yusuf²

¹Regional Seismic Center 3, Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG), Sidoarjo, Indonesia
²Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG), Instrument and Calibration Division, Jakarta, Indonesia

Abstract:

Superconducting Gravimeters are the most sensitive instruments to measure gravity changes continuously in low frequencies. There is one Superconducting Gravimeter installed in Cibinong in Indonesia. Using this SG, we studied gravity changes during Indonesia’s large earthquakes. Global CMT recorded 17 earthquakes in Indonesia with magnitude moment (Mw) > 6 from January until December 2011. We investigated possible applications of Superconducting Gravimeter to detect anomalous signals before these earthquakes occurred. Using Spectrogram Analysis, we found anomalous signals a few hours before these earthquakes. Anomalous frequenciesare between 0.03 Hz up to 0.20 Hz. These frequencies are correlated with stress accumulation during the nucleation of a main shock. We concluded that a Superconducting Gravimeter can be used to support earthquake early warning systems. Keywords: Superconducting Gravimeter, Earthquake, Precursor