Implikasi Sesar Kendeng Terhadap Bahaya Gempa dan Pemodelan Percepatan Tanah di Permukaan di Wilayah Surabaya

Kota Surabaya merupakan ibukota propinsi Jawa Timur Berdasarkan data Badan Pusat Statistik, Surabaya dapat dikategorikan sebagai kota yang cukup padat. Salah satu bahaya gempa di wilayah Surabaya berasal dari sesar Kendeng yang terbukti aktif dengan pergerakan 5 milimeter per tahun. Implikasi sesar kendeng terhadap bahaya gempa di wilayah Surabaya dapat dilakukan salah satunya dengan metode Deterministic Seismic Hazard Analisis (DSHA). Perhitungan bahaya gempa dengan metode DSHA dilakukan menggunakan modifikasi software CRISIS 2007 yang akan menghasilkan percepatan tanah di batuan dasar. Hasil dari DSHA selanjutnya dipergunakan untuk memodelkan percepatan tanah di permukaan pada lokasi (site) yang ditinjau di wilayah Surabaya dengan menggunakan software Nonlinear Earthquake site Response Analyses (NERA). Nilai percepatan tanah di batuan dasar untuk wilayah Surabaya dengan memperhitungkan keberadaan sesar Kendeng memiliki nilai berkisar antara 0.26g - 0.71g. Model percepatan tanah di permukaan untuk lokasi yang ditinjau pada koordinat 112,74830 BT dan 7,2890 LS memiliki nilai maksimum sekitar 0.34g. ============================================================================================== Surabaya is the capital of East Java province which can be categorized as a fairly dense city based on the data from Central Statistics Agency. One of the earthquake hazards in Surabaya territory came from the fault of Kendeng which was proved as an active fault with 5 millimeters movements per year. The implication of Kendeng’s fault towards the danger of earthquake in Surabaya area can be conducted by using Deterministic Seismic Hazard Analysis (DSHA) method. The earthquake hazard’s calculation with DSHA method has been done by using the modification of CRISIS 2007 software which would generate the ground acceleration in the bedrock. The further result of DSHA was used for modelling the ground acceleration on the location (site) surface that was observed in Surabaya territory using Nonlinear Earthquake site Response Analysis (NERA) software. The ground acceleration value in the Surabaya’s bedrock area by considering its Kendeng’s fault existence had a value ranging from 0.26g - 0.71g. The ground acceleration model on the surface of the target location at 112.74830 BT and 7.2890 LS coordinates had a maximum value approximately 0.34g