Estimasi Coseismic Slip Gempa Mentawai 2010 M 7,8 Berdasarkan Pengamatan 1HZ GNSS

Tri Wardhana, Rahmadi (2026) Estimasi Coseismic Slip Gempa Mentawai 2010 M 7,8 Berdasarkan Pengamatan 1HZ GNSS. Masters thesis, Institute Teknologi Sepuluh November.

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Abstract

Gempabumi Mentawai 25 Oktober 2010 ($M_\text{w}\ 7.8$) merupakan peristiwa tsunami earthquake klasik yang memicu tsunami di sepanjang Kepulauan Pagai, meskipun guncangan di darat dirasakan relatif lemah. Penelitian ini bertujuan untuk mengkuantifikasi nilai pergeseran coseismic murni yang steril dari kontaminasi deformasi early afterslip, serta memvalidasi geometri bidang patahan secara interdisipliner. Pemrosesan data GPS kinematik 15 detik dari Jaringan Sumatra GPS Array (SuGAr) dilakukan menggunakan strategi Precise Point Positioning (PPP) dan pembersihan derau statistik $\pm 3\sigma$. Melalui penguncian jendela temporal pada epok $<1$ menit pasca-gempa, diperoleh nilai coseismic jump murni dengan komponen horizontal maksimum berpusat di Pulau Pagai (Stasiun BSAT: East -25.43 cm, North -18.31 cm; Stasiun SLBU: East -17.28 cm, North -22.24 cm) yang berorientasi searah parit laut (trench-ward motion), disertai amblesan vertikal (subsidence) konstan sebesar 4–6 cm. Tumpang-susun (overlay) spasial dengan 38 titik hiposenter aftershocks hasil relokasi the Double-Difference (HypoDD) mengonfirmasi bahwa bidang patahan aktif berimpit pada Nodal Plane 1 (Strike 316°, Dip 8°, Slip 96°) dengan kedalaman gempa utama terkoreksi pada 27.88 km. Pemodelan inversi slip patahan menggunakan pembobot regulasi Tikhonov optimum ($\alpha = 0.01 - 0.02$) hasil analisis L-Curve mengestimasi pelepasan energi sebesar $M_\text{w}\ 7.73–7.74$ pada dimensi bidang ruptur 160 km × 135 km. Hasil integrasi ini membuktikan secara fisis bahwa robekan utama (main slip patch) murni terkonsentrasi di baji sedimen dangkal lepas pantai (shallow updip zone), yang memberikan penjelasan mekanis tuntas atas bangkitnya gelombang tsunami masif.
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The Mentawai earthquake of October 25, 2010 ($M_\text{w}7.8$) was a tsunami earthquake event. classic that triggered a tsunami along the Archipelago Pagai, although ground shaking felt relatively weak . This study aims to quantify mark shift coseismic pure sterile from contamination deformation early afterslip , and validate geometry field fault in a way interdisciplinary . 15- second kinematic GPS data processing from Network Sumatra GPS Array ( SuGAr ) was carried out using the Precise Point Positioning (PPP) strategy and cleaning noise statistics $\pm 3\sigma$. By locking the temporal window at $<1$ the post-earthquake minute epoch, the coseismic jump value is obtained. pure with maximum horizontal component centered on Pagai Island ( BSAT Station : East -25.43 cm, North -18.31 cm; SLBU Station : East -17.28 cm, North -22.24 cm) which is oriented one way ditch sea ( trench-ward motion ), accompanied by subsidence constant vertical ( subsidence ) 4–6 cm . Spatial overlay with 38 points hypocenter aftershocks results relocation the Double-Difference ( HypoDD ) confirms that field fault active coincides with Nodal Plane 1 (Strike 316°, Dip 8°, Slip 96°) with the corrected depth of the main earthquake at 27.88 km. Fault slip inversion modeling using the optimum Tikhonov regulation weighting ( $\alpha = 0.01 - 0.02$ ) results of the L-Curve analysis estimate release energy as big as $M_\text{w}7.73–7.74$ on the dimensions of the rupture plane $160\text{ km} \times 135\text{ km}$. The results of this integration prove that in a way physical that tear main ( main slip patch ) pure concentrated in the wedge sediment shallow off beach ( shallow updip zone ), which provides explanation mechanical complete on rise massive tsunami waves.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Gempa Mentawai 2010, Coseismic Slip, Precise Point Positioning (PPP), GNSS 1Hz, 2010 Mentawai Earthquake, Coseismic Slip, 1Hz GNSS, Precise Point Positioning (PPP), Earthquake Source Inversion.
Subjects:	G Geography. Anthropology. Recreation > GB Physical geography > GB651 Subsidences (Earth movements)
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Civil Engineering > 22101-(S2) Master Thesis
Depositing User:	Rahmadi Tri Wardhana
Date Deposited:	05 Aug 2026 04:23
Last Modified:	05 Aug 2026 04:23
URI:	http://repository.its.ac.id/id/eprint/142205

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