IDENTIFIKASI RANGKAIAN GEMPA BUMI PENDAHULUAN (FORESHOCKS) DENGAN PENDEKATAN KORELASI SILANG SINYAL SEISMIK TEMPLATE (STUDI KASUS RANGKAIAN GEMPA BUMI KARO 2017)
DOI:
https://doi.org/10.23887/jstundiksha.v6i2.11800Keywords:
foreshock, gempa, BMKG, matched filterAbstract
Penelitian ini berhasil membuktikan bahwa pendekatan korelasi silang sinyal seismik dapat digunakan untuk mendeteksi kejadian seismik menggunakan waveform dari jaringan BMKG (Badan Meteorologi Klimatologi dan Geofisika). Pendeteksian ini dilakukan untuk melengkapi kejadian gempa bumi yang belum tercatat pada katalog reguler BMKG karena berbagai keterbatasan. Adanya rangkaian kejadian gempa pendahuluan (foreshock sequence) sebelum kejadian gempa Karo M 5,6 tanggal 16 Januari 2017 berhasil teridentifikasi. Tujuan dari penelitian ini adalah melakukan identifikasi kejadian gempa bumi pendahuluan (foreshocks) dengan memanfaatkan data sinyal template gempa bumi M 3,9 yang sebelumnya dianggap sebagai satu-satunya foreshock dalam rangkaian kejadian ini. Penelitian ini berhasil mendeteksi 12 kejadian gempa pendahuluan (foreshocks) setelah diterapkan metode deteksi berbasis korelasi silang. Foreshock mulai terdeteksi pada tanggal 14 Januari 2017 atau dua hari sebelum gempa utama. Magnitudo gempa pendahuluan semakin meningkat secara sistematis sampai kejadian gempa pendahuluan terbesar. Penelitian ini berimplikasi pada manfaat penerapan metode deteksi berbasis waveform untuk mendukung pemahaman fisis sumber gempa dan prediksi gempa bumi di Indonesia.
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