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Engineering a one-second variometer for seismomagnetic identification |
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Mahmud Yusuf |
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Meteorology Climatology and Geophysical Agency Indonesia |
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Geomagnetic observations are made to record the variations of the geomagnetic all components in a continuous manner. Tectonic activity causing earthquakes resulted in changes in the geomagnetic field. Variometer system engineering has been done with a sampling rate of 1 second at Pelabuhan Ratu and Kupang station, then analysed recording on anomaly during earthquake. The variometer recorded an anomalous change of geomagnetic during an earthquake with magnitude 6.6 SR on October 19, 2016 at a depth of 614 Km with an epicentre location in the Java Sea northeast direction which is 276 Km from Pelabuhanratu geophysical station, the earthquake caused magnetic disturbance during 4 minutes with a maximum amplitude of 40 nT (nanoTesla), and visible phase P and S waves with a time difference of 1 minute. And the earthquake in Flores on December 5, 2016 which magnitude 6.3 SR. Variometer at Kupang geophysical station experience magnetic disturbance for 5 minutes with maximum amplitude of 20 nT, phase seismic waves P and S visible on magnetic variation with difference time 50 seconds. Anomalies are seen several hours before an earthquake showing the variation pattern of X and Y components forming the same pattern, it can be suspected as earthquake precursors. |
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Instrumentation |
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poster |
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