Rachman, Tri Deni (2026) Estimasi Sumber Gempa Bumi Bawean M6.5 2024 Berdasarkan Integrasi Data Geodetic Dan Seismic Serta Implikasinya Terhadap Seismic Hazard Di Jawa Timur. Masters thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Rangkaian gempabumi Bawean yang diawali pada 22 Maret 2024 merupakan fenomena seismik signifikan di zona aktivitas rendah (low seismicity) di Laut Jawa yang menyebabkan kerusakan masif di Pulau Bawean. Penelitian ini bertujuan untuk mengidentifikasi karakteristik parameter sumber gempa dan distribusi perubahan tegangan pasca-gempa utama M6.5. Metodologi yang digunakan meliputi relokasi hiposenter dengan metode Double-Difference (HypoDD) terhadap 712 kejadian serta pemodelan perubahan tegangan Coulomb menggunakan perangkat lunak Coulomb 3.4 berdasarkan parameter mekanisme fokus dari USGS serta dilakukan perhitungan slip deformation dengan menganalisa data dari 14 stasiun GNSS INACORS. Hasil relokasi menunjukkan distribusi gempa susulan memanjang sekitar ~22 km x 20 km dengan orientasi Barat Daya-Timur Laut, yang mengidentifikasi struktur sesar geser sinistral (sinistral strike-slip) pada zona Sesar Muria yang sebelumnya dorman selama lebih dari satu abad. Pemodelan tegangan Coulomb menunjukkan adanya peningkatan tegangan (stress loading) di sektor barat daya, utara, dan timur laut yang secara spasial konsisten dengan konsentrasi gempa susulan. Namun, ditemukan anomali peningkatan tegangan pada sisi selatan dan timur yang bersifat quiescent (sepi gempa susulan), mengindikasikan adanya akumulasi energi yang belum terlepaskan. Hasil inversi data geodetik menunjukkan bahwa akumulasi pelepasan energi pada bidang sesar mencapai nilai pergeseran maksimum (maximum slip) sebesar ±3,8 meter, yang terkonsentrasi pada zona asperity di kedalaman sekitar 25 kilometer. Temuan ini memberikan urgensi bagi evaluasi ulang bahaya seismik di Jawa Timur, khususnya terkait potensi reaktivasi segmen-segmen sesar di sekitar Pulau Bawean yang dapat mengancam keselamatan penduduk dan stabilitas infrastruktur.
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The Bawean earthquake sequence, which commenced on March 22, 2024, represents a significant seismic phenomenon in the low-seismicity zone of the Java Sea, causing massive damage on Bawean Island. This study aims to identify the source parameter characteristics and the distribution of post-mainshock (M6.5) stress changes. The methodology involves hypocenter relocation using the DoubleDifference (HypoDD) method for 712 events, Coulomb stress change modeling using Coulomb 3.4 software based on USGS focal mechanism parameters, and slip deformation calculations by analyzing data from 14 INACORS GNSS stations. Relocation results show an aftershock distribution extending approximately 22 km x 20 km with a Southwest-Northeast orientation, identifying a sinistral strike-slip fault structure within the Muria Fault zone, which had been dormant for over a century. Coulomb stress modeling indicates stress loading in the southwest, north, and northeast sectors, spatially consistent with aftershock concentrations. However, anomalous stress increases were found on the southern and eastern sides, which remain quiescent, suggesting unreleased energy accumulation. Geodetic data inversion results show that energy release accumulation on the fault plane reached a maximum slip of ±3.8 meters, concentrated in an asperity zone at a depth of approximately 25 kilometers. These findings emphasize the urgency of reevaluating seismic hazards in East Java, particularly regarding the potential reactivation of fault segments around Bawean Island that could threaten public safety and infrastructure stability.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Gempabumi Bawean, Relokasi HypoDD, Tegangan Coulomb, Sesar Muria, Inversi Geodetik, bahaya seismik, Bawean Earthquake, HypoDD Relocation, Coulomb Stress, Muria Fault, Geodetic Inversion, seismic hazard. |
| Subjects: | G Geography. Anthropology. Recreation > G Geography (General) G Geography. Anthropology. Recreation > G Geography (General) > G109.5 Global Positioning System |
| Divisions: | Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geomatics Engineering > 29101-(S2) Master Thesis |
| Depositing User: | Tri Deni Rachman |
| Date Deposited: | 04 Feb 2026 02:56 |
| Last Modified: | 04 Feb 2026 02:56 |
| URI: | http://repository.its.ac.id/id/eprint/131870 |
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