Analisis Klaster Gempa Bumi Di Wilayah Sumatera Utara Dengan Metode Double-Difference

Purba, Rini Kumalasari (2026) Analisis Klaster Gempa Bumi Di Wilayah Sumatera Utara Dengan Metode Double-Difference. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Wilayah Sumatera Utara merupakan zona tektonik aktif yang dipengaruhi oleh interaksi kompleks antara aktivitas subduksi lempeng Indo-Australia dan pergerakan Sesar Sumatera. Akurasi penentuan lokasi pusat gempa bumi (hiposenter) sangat krusial untuk pemodelan seismotektonik dan mitigasi bencana. Penelitian ini bertujuan untuk meningkatkan kepresisian relokasi hiposenter gempa bumi di wilayah Pulau Sumatra melalui implementasi metode relokasi Double-Difference dengan aplikasi HypoDD dan menganalisis clustering berdasarkan distribusi spasial gempa bumi. Metode relokasi Double-Difference digunakan untuk mengidentifikasi segmen sesar aktif. Data gempa bumi yang digunakan berasal dari katalog stasiun seismik lokal selama periode 2019–2024. Aplikasi metode HypoDD secara signifikan berhasil mereduksi nilai Root Mean Square (RMS) residual rata- rata kedatangan fase seismik dari 0.79373 menjadi 0.33888, yang mengindikasikan peningkatan akurasi lokasi hiposenter. Analisis klasterisasi gempa bumi mengidentifikasi total 10 klaster yang menunjukkan korelasi kuat dengan struktur geologi sekitarnya. Klaster gempa dangkal di wilayah Tarutung didominasi oleh mekanisme sesar mendatar (strike-slip), yang secara definitif mengonfirmasi bahwa Segmen Renun adalah segmen aktif Sesar Sumatera dengan aktivitas intensif. Selain itu, teridentifikasi pola swarm dengan magnitudo rendah dan kedalaman sangat dangkal (<15 km) di Cekungan Toba (Klaster 2), yang mengindikasikan adanya kontribusi proses tektonik-magmatis. Klaster gempa berkedalaman menengah hingga dalam (70–150 km) berasosiasi kuat dengan aktivitas subduksi dizona megathrust intraslab Sumatera. Secara keseluruhan, penelitian ini berhasil memetakan pola distribusi spasial sumber gempa secara lebih terperinci, memberikan kontribusi penting untuk pembaruan peta bahaya gempa bumi dan penentuan zona sesar aktif di Sumatera Utara.
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North Sumatra is an active tectonic zone influenced by the complex interaction between the subduction of the Indo-Australian plate and the movement of the Sumatra Fault. Accurate determination of earthquake hypocenter locations is crucial for seismotectonic modeling and disaster mitigation. This study aims to improve the precision of earthquake hypocenter location in this region through the implementation of the Double-Difference (HypoDD) relocation method and to analyze clustering based on the spatial distribution of earthquakes to identify active fault segments. The earthquake data used came from local seismic station catalogs during the period 2008–2024. The application of the HypoDD method significantly reduced the Root Mean Square (RMS) value of the average seismic phase arrival residual from 0.79373 to 0.33888, indicating an increase in the accuracy of the hypocenter location. Earthquake clustering analysis identified a total of 10 clusters that showed a strong correlation with the surrounding geological structure. The shallow earthquake cluster in the Tarutung region was dominated by a strike-slip fault mechanism, which definitively confirmed that the Renun Segment is an active segment of the Sumatra Fault with intense activity. In addition, a swarm pattern with low magnitude and very shallow depth (<15 km) was identified in the Toba Basin (Cluster 2), indicating the contribution of tectonic-magmatic processes. The cluster of medium- to deep-depth earthquakes (70–150 km) is strongly associated with subduction activity in the Sumatra intraslab megathrust zone. Overall, this study successfully mapped the spatial distribution pattern of earthquake sources in greater detail, contributing significantly to the updating of earthquake hazard maps and the determination of active fault zones in North Sumatra.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Klaster Gempa Bumi , Double-Difference, Sumatera Utara, Seismotektonik, Sesar aktif. Earthquake Clusters, Double-Difference, North Sumatra, Seismotectonics, Active Faults.
Subjects:	Q Science > QE Geology > QE538.8 Earthquakes. Seismology
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Physics Engineering > 30101-(S2) Master Thesis
Depositing User:	Rini Kumalasari Purba
Date Deposited:	12 Feb 2026 02:33
Last Modified:	12 Feb 2026 02:33
URI:	http://repository.its.ac.id/id/eprint/132360

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