Identifikasi Perubahan Gayaberat Akibat Gempa Bumi Menggunakan Data Satelit GRACE di Indonesia (2022-2024)

Salsabilla, Eka Salma (2025) Identifikasi Perubahan Gayaberat Akibat Gempa Bumi Menggunakan Data Satelit GRACE di Indonesia (2022-2024). Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Indonesia merupakan wilayah tektonik aktif yang kerap mengalami gempa bumi akibat interaksi lempeng di zona subduksi. Aktivitas seismik ini dapat menyebabkan deformasi litosfer yang berdampak pada perubahan distribusi massa dan terekam sebagai variasi gayaberat. Penelitian ini bertujuan untuk menganalisis pola perubahan gayaberat menggunakan metode Principal Component Analysis (PCA) terhadap data Equivalent Water Height (EWH) satelit GRACE periode 2002–2023 pada wilayah-wilayah aktif gempa, yaitu Sulawesi, Ternate, dan Papua. Analisis dilakukan dalam dua tahap, yaitu sebelum dan sesudah dilakukan reduksi tren dan musiman, guna memisahkan sinyal jangka panjang serta fluktuasi musiman dari anomali yang berpotensi terkait dengan aktivitas seismik. Hasil PCA menunjukkan bahwa komponen utama (PC) pada masing-masing wilayah memiliki kontribusi variasi yang signifikan, seperti Mode 1 Indonesia (43,39%), Sumatra (52,88%), Jawa (66,29%), Sulawesi (54,54%), Kalimantan (56,92%), Nusa Tenggara (63,97%), Banda (72,27%), Ternate (57,67%), Papua (55,33%), dan Chile (91,29%), yang didominasi oleh tren jangka panjang. Fluktuasi pada PC juga bertepatan dengan waktu terjadinya gempa-gempa besar, seperti gempa Nabire 2004, Manokwari 2009, Palu 2018, dan Ternate 2019. Sementara itu, pola spasial EOF berhasil mengidentifikasi distribusi anomali gayaberat yang sejalan dengan lokasi-lokasi gempa, terutama pada zona subduksi dan jalur sesar aktif. Setelah reduksi, sinyal deformasi akibat gempa lebih mudah dikenali, dengan spike PC yang lebih tajam dan pola EOF yang lebih fokus. Hal ini menunjukkan bahwa metode PCA efektif dalam mendeteksi perubahan gayaberat akibat deformasi tektonik, dan data GRACE dapat digunakan sebagai salah satu alat pemantauan geodinamika di wilayah Indonesia.
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Indonesia is an active tectonic region that frequently experiences earthquakes due to plate interactions in subduction zones. This seismic activity can cause lithospheric deformation, which affects mass distribution and is recorded as variations in gravity. This study aims to analyze patterns of gravity changes using Principal Component Analysis (PCA) on Equivalent Water Height (EWH) data from the GRACE satellite for the period 2002–2023 in active earthquake regions, namely Sulawesi, Ternate, and Papua. The analysis was conducted in two stages: before and after trend and seasonal reduction, to separate long-term signals and seasonal fluctuations from anomalies potentially related to seismic activity. The PCA results show that the principal components (PC) in each region contribute significantly to variations, such as Mode 1 Indonesia (43.39%), Sumatra (52.88%), Java (66.29%), Sulawesi (54.54%), Kalimantan (56.92%), Nusa Tenggara (63.97%), Banda (72.27%), Ternate (57.67%), Papua (55.33%), and Chile (91.29%), which are dominated by long-term trends. Fluctuations in PC also coincide with the timing of major earthquakes, such as the 2004 Nabire earthquake, the 2009 Manokwari earthquake, the 2018 Palu earthquake, and the 2019 Ternate earthquake. Meanwhile, the spatial pattern of EOF successfully identified the distribution of gravity anomalies aligned with earthquake locations, particularly in subduction zones and active fault lines. After reduction, the deformation signals caused by earthquakes are easier to recognize, with sharper PC spikes and more focused EOF patterns. This indicates that the PCA method is effective in detecting gravity changes caused by tectonic deformation, and GRACE data can be used as one of the tools for geodynamic monitoring in the Indonesian region.y8

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Satelit GRACE, Gayaberat, PCA, Anomali Gayaberat, Redistribusi Massa, satellite, Gravity, PCA, Gravity Anomaly, Mass Redistribution.
Subjects:	G Geography. Anthropology. Recreation > GB Physical geography > GB1003.2 Groundwater. G Geography. Anthropology. Recreation > GB Physical geography > GB1197.7 Groundwater flow. Reservoirs G Geography. Anthropology. Recreation > GB Physical geography > GB651 Subsidences (Earth movements)
Divisions:	Faculty of Civil Engineering and Planning > Geomatics Engineering > 29202-(S1) Undergraduate Thesis
Depositing User:	Eka Salma Salsabilla
Date Deposited:	25 Jul 2025 03:24
Last Modified:	25 Jul 2025 03:24
URI:	http://repository.its.ac.id/id/eprint/121450

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