ANOMALI SINYAL SEBELUM GEMPABUMI SIGNIFIKAN DI INDONESIA YANG TERDETEKSI OLEH SUPERCONDUCTING GRAVIMETER

Fajar Rachmadi Priyambada, Mahmud Yusuf, Ervan Dany Variandy

Abstract


ABSTRAK

Indonesia merupakan salah satu negara yang memiliki aktivitas kegempaan yang cukup tinggi. Pada studi ini dilakukan penelitian tentang perubahan nilai gravity selama gempabumi terjadi dengan menggunakan Superconducting Gravimeter (SG) yang terpasang di Badan Informasi Geospasial (BIG). Tujuan penelitian ini adalah untuk mencari anomali yang terekam oleh SG sesaat sebelum gempabumi tersebut terjadi. Metode yang digunakan adalah analisis spektogram dari data SG selama tahun 2011 didapatkan 17 gempabumi signifikan yang mempunyai Mw > 6. Hasil penelitian menunjukkan anomali sinyal beberapa jam sebelum kejadian gempabumi terjadi. Anomali tersebut terdapat pada frekuensi 0.03 Hz hingga 0.20 Hz, frekuensi ini berkorelasi dengan akumulasi stress dari nukleasi gempa utama. Dari penelitian ini disimpulkan bahwa SG mampu merekam sinyal gempabumi dengan cukup baik. Tingkat sensitifitas dan kestabilan SG yang sangat baik, dapat dimanfaatkan sebagai pendukung dalam memonitor adanya gempabumi, dan prekursor gempabumi.

 

ABSTRACT

Indonesia is one of the most country which had high level of seismic activities. In this study we had research about gravity change’s value during earthquakes by using Superconducting Gravimeter (SG) which installed on Badan Informasi Geospasial, Cibinong. Superconducting Gravimeter is the most sensitive instrument to measure gravity change’s continuously in low frequencies. This research purposed to found anomaly that recorded by SG before an earthquake happened. During 2011, we found significantly earthquakes with Mw > 6. Using spectrogram analysis, we got signal anomaly few hours before earthquake happened. Frequencies of anomaly are between 0.03 Hz up to 0.20 Hz,  this frequencies are correlated with stress accumulation of nucleation mainshock. We concluded Superconducting Gravimeter can be use for supporting research about earthquake early warning system. Sensitivity and stability are so good and can be able to support monitoring earthquakes, and earthquake’s precursor.

 


Keywords


Superconducting Gravimeter, Gempabumi, Prekursor

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DOI: http://dx.doi.org/10.24895/JIG.2016.22-2.491

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