Pemetaan Slab Subduksi dan Sesar Sumatra di Selat Sunda Berdasarkan Tomografi Vp, Vs, dan Vp/Vs

Suriani, Putri Dwi Suriani (2025) Pemetaan Slab Subduksi dan Sesar Sumatra di Selat Sunda Berdasarkan Tomografi Vp, Vs, dan Vp/Vs. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Selat Sunda memiliki struktur tektonik kompleks akibat perubahan arah subduksi Sumatra, menghasilkan sesar geser kanan seperti Sesar Sumatra dan Mentawai. Keberadaan Sesar Sumatra di Selat Sunda masih diperdebatkan dengan tiga teori: berakhir sebagai graben, memanjang ke palung subduksi, atau menerus ke Jawa Barat. Penelitian sebelumnya menunjukkan zona subduksi mengalami pembelokan dari kompresi pada kedalaman 100-300 km, dengan relokasi hiposenter mengungkap pembagian zona gempa berdasarkan kedalaman dangkal, menengah, dan dalam. Untuk merekonstruksi struktur Selat Sunda dan keberadaaan Sesar Sumatra, penelitian ini memanfaatkan metode tomografi seismik secara simultan menggunakan program Simulps12. Data yang digunakan dalam penelitian merupakan data waktu tiba dari repository BMKG dengan batas wilayah adalah -9,608°LS hingga -3,674°LS dan 100,261°BT hingga 108,556°BT dan waktu rekaman data selama 2008 hingga 2024. Melalui model inisial AK135, struktur dibawah permukaan dapat teridentifikasi dengan baik. Zona lemah Teluk Semangko ditemukan dalam sayatan CC’ yang ditandai dengan adanya anomali Vp, Vs, dan Vp/Vs yang rendah diikuti dengan akumulasi kejadian gempabumi di kawasan sesar. Selain itu, aktivitas Sesar Sumatra di Teluk Semangko dapat diidentifikasi keberadaannya didekat Gunung Tanggamus. Pola subduksi lempeng dapat diidentifikasi melalui tomogram vertikal GG’ yang berada di Jawa Barat. Pada tomogram GG’ juga ditemukan anomaly Vp dan Vs rendah dengan diikuti meningkatnya Vp/Vs. Anomali tersebut diperkirakan akibat adanya kawasan vulkanik Gunung Salak.
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The Sunda Strait has a complex tectonic structure due to changes in the direction of Sumatra subduction, resulting in right-slip faults such as the Sumatra and Mentawai Faults. The existence of the Sumatra Fault in the Sunda Strait is still debated with three theories: ending as a graben, extending into the subduction trough, or continuing into West Java. Previous research shows the subduction zone undergoes deflection from compression at depths of 100-300 km, with hypocenter relocation revealing the division of earthquake zones based on shallow, intermediate and deep depths. To reconstruct the structure of the Sunda Strait and the presence of the Sumatra Fault, this study utilizes the seismic tomography method simultaneously using the Simulps12 program. The data used in the study are time-arrived data from the BMKG repository with the boundaries of -9.608°LS to -3.674°LS and 100.261°BT to 108.556°BT and the data recording time from 2008 to 2024. Through the AK135 initial model, the subsurface structure can be well identified. The weak zone of Semangko Bay is found in the CC' incision characterized by the presence of low Vp, Vs, and Vp/Vs anomalies followed by the accumulation of earthquake events in the fault area. In addition, the Sumatra Fault activity in Semangko Bay can be identified near Mount Tanggamus. Plate subduction pattern can be identified through the vertical tomogram of GG' located in West Java. The GG' tomogram also shows low Vp and Vs anomalies followed by increasing Vp/Vs. The anomaly is thought to be due to the presence of Mount Salak volcanic area.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Relokasi Hiposenter, Subduksi, Selat Sunda, Sesar Sumatra, Tomografi Hypocenter Relocation, Subduction, Sumatran Fault, Sunda Strait, Tomography
Subjects:	Q Science > QE Geology > QE538.5 Seismic tomography; Seismic waves. Elastic waves
Divisions:	Faculty of Civil Engineering and Planning > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User:	Putri Dwi Suriani
Date Deposited:	22 Jul 2025 06:06
Last Modified:	22 Jul 2025 06:06
URI:	http://repository.its.ac.id/id/eprint/120471

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