ANALISIS BAHAYA GEMPA BUMI KABUPATEN DAN KOTA BEKASI BERBASIS SKENARIO
Abstract
Secara seismotektonik, Kabupaten dan Kota Bekasi dipengaruhi oleh gempa bumi yang berasal dari zona subduksi di selatan Jawa dan patahan aktif yang ada di sekitar wilayah tersebut. Penelitian terbaru memaparkan adanya patahan aktif kepanjangan dari patahan Baribis, yang melintang dari Purwakarta, Cibatu (Bekasi), Tangerang, dan Rangkasbitung yang memiliki kemungkinan menimbulkan gempa bumi di masa depan. Penelitian ini bertujuan untuk menganalisis bahaya gempa bumi di Kabupaten dan Kota Bekasi menggunakan pendekatan skenario gempa bumi. Data historis dan parameter gempa bumi di sekitar area penelitian diperoleh dari BMKG, USGS, ISC dan katalog global CMT. Geometri patahan Baribis merujuk pada penelitian Koulali et al. Event based dan simple fault source PSHA (Probabilistic Seismic Hazard Analysis) dipergunakan untuk memperkirakan bahaya gempa bumi di area studi. Peak Ground Acceleration (PGA) di batuan dasar yang sesuai dengan probabilitas terlampaui 2% dalam 50 tahun dihitung. Hasil penelitian menunjukkan tingkat bahaya gempa bumi di Kabupaten dan Kota Bekasi dari historis gempa bumi yang pernah terjadi maupun skenario gempa bumi yang bersumber dari kepanjangan patahan Baribis yang kemungkinan dapat terjadi di masa depan. Hasil penelitian diharapkan dapat dimanfaatkan dalam perencanaan strategis untuk mitigasi gempa bumi di Kabupaten dan Kota Bekasi.
Seismotectically, Bekasi Regency and Bekasi City are affected by earthquakes originating from subduction zones in the south of Java and active faults around the area. The latest research describes the existence of active faults extending from the Baribis fault, which crosses from Purwakarta, Cibatu (Bekasi), Tangerang and Rangkasbitung which have the possibility of causing future earthquakes. This study aims to analyze seismic hazards in Bekasi Regency and Bekasi City based on an earthquake scenario approach. Historical data and earthquake parameters around the study area were obtained from BMKG, USGS, ISC and the CMT global catalog. The Baribis fault geometry refers to the study of Koulali et al. Event based and simple fault source PSHA (Probabilistic Seismic Hazard Analysis) were used to estimate seismic hazards in the study area. Peak Ground Acceleration (PGA) at bedrock level corresponding to 2% exceedance of 50 years’ probability was calculated. The results of the study show the level of seismic hazard in Bekasi Regency and Bekasi City from the historical earthquakes that have occurred as well as the earthquake scenario that originated from the extension of the Baribis fault which might occur in the future. The results of the study are expected to be utilized in strategic planning for earthquake mitigation in Bekasi Regency and Bekasi City.
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