Electronic Theses and Dissertation

Pulau Sumatera memiliki tingkat seismisitas yang tinggi karena dikelilingi oleh lempeng tektonik aktif yang mengakibatkan adanya 3 zona aktif yaitu Zona Subduksi, Patahan Sumatera dan Magmatic Arc. Hingga saat ini telah banyak penelitian yang dilakukan pada gempa yang terjadi di Pulau Sumatera, namun penelitian tersebut masih bersifat konvensional (Picking first polarity Gelombang). Tujuan penelitian ini adalah untuk memetakan distribusi gempa merusak Pulau Sumatera, memperbaiki parameter gempa merusak Pulau Sumatera dan menginterpretasi karakteristik tektonik Pulau Sumatera. Metodologi yang digunakan adalah analisis inversi waveform yang menggunakan seluruh bentuk gelombang seismik, baik gelombang badan dan permukaan untuk menghasilkan representatif dari sumber gempa bumi dengan lebih lengkap. Pendekatan ini memberikan solusi terbaik (fit) dengan distribusi solusi dari variasi parameter model yang diprediksi. Oleh karena itu metode Inversi Momen Tensor berbasis waveform dapat memperbaiki nilai-nilai parameter gempa bumi seperti origin time, lokasi, magnitudo, waktu kejadian, dan kedalaman gempa bumi. Data yang digunakan terdiri dari data seismisitas, waveform, dan Green function. Proses inversi dilakukan dengan membandingkan data waveform sintetik (hasil perhitungan) dan observasi yang diperoleh dari tiap stasiun seismik. Hasil penelitian ini menunjukkan distribusi gempa bumi merusak di Pulau Sumatera terjadi pada kedalaman

Sumatra Island has a high level of seismicity due to its location within an active tectonic setting resulting in three major active zones the Subduction Zone, the Sumatra Fault, and the Magmatic Arc. Numerous studies have been conducted on earthquakes in Sumatra however most of them rely on conventional methods, such as picking the first polarity of seismic waves. This study aims to map the distribution of destructive earthquakes in Sumatra refine their seismic parameters, and interpret the island's tectonic characteristic. The methodology employed is waveform inversion analysis which utilizes the entire seismic waveform both body and surface waves to provide a more comprehensive representation of earthquake sources. This approach offers the best-fit solution by incorporating the distribution of solutions from various predicted model parameters. Therefore, based Moment Tensor Inversion can improve earthquake parameters such as origin time, location, magnitude, event time, and depth. The data used in this study include seismicity data, waveform, and Green function. The inversion process involves comparing synthetic waveform data (calculated results) with observed data recorded at seismic stations. The results indicate that the distribution of destructive earthquakes in Sumatra occurs at depths of less than 25 km, specifically along the Sumatra Fault. The refined earthquake parameters exhibit high quality, with a misfit value of less than 0.5. Based on moment tensor inversion it was found that the 2016 Pidie Jaya and 2017 Berastagi earthquakes were caused by left-lateral strike-slip faulting with an oblique component. Meanwhile, five other earthquakes Sidimpuan 2011, Tangse 2013, Takengon 2013, Pasaman 2022, and Tarutung 2022 were triggered by right-lateral strike-slip faulting.