Electronic Theses and Dissertation

Wilayah Pamir terletak di perbatasan Tajikistan-Kyrgyzstan yang merupakan kawasan dengan aktivitas seismik tinggi akibat tumbukan antara Lempeng India dan Eurasia. Data gempa yang digunakan dalam penelitian ini diperoleh dari rekaman jaringan seismometer 8H dan 9H milik GeoForschungsZentrum (GFZ) yang terpasang di wilayah studi selama periode September 2015–Maret 2016. Tahapan penelitian meliputi picking manual waktu tiba gelombang P dan S, penentuan lokasi awal hiposenter, relokasi menggunakan perangkat lunak HypoDD dengan metode Double-Difference, serta interpretasi struktur patahan berdasarkan hasil relokasi. Metode ini mampu meningkatkan presisi lokasi hiposenter dengan membandingkan perbedaan waktu tiba gelombang antar pasangan gempa yang berdekatan sehingga mengurangi pengaruh ketidakpastian model kecepatan.
Hasil lokalisasi awal menunjukkan kejadian gempa bumi yang terdistribusi di Wilayah Pamir, dengan kedalaman dangkal hingga menengah. Setelah proses relokasi tahap kedua, gempa membentuk pola lineasi yang lebih jelas dan konsisten dengan arah struktur geologi regional. Distribusi pasca-relokasi ini mengindikasikan keberadaan jalur patahan aktif bawah permukaan. Selain mengonfirmasi keterkaitan dengan patahan utama seperti Main Pamir Thrust dan Sarez–Karakul Fault, analisis spasial juga memperlihatkan adanya klaster-klaster gempa yang mengindikasikan keberadaan patahan baru yang berada di Wilayah Alichur terletak di Tajikistan bagian timur, tepatnya di Wilayah Gorno-Badakhshan Autonomous Region (GBAO), di kawasan Dataran Tinggi Pamir. Keberadaan jalur patahan yang belum terkonfirmasi ini menunjukkan bahwa dinamika tektonik di Wilayah Pamir masih menyimpan kompleksitas yang belum sepenuhnya terungkap.
Kata Kunci: Pamir, Relokasi Gempa Bumi, Double-Difference, Patahan Aktif, Patahan Belum Teridentifikasi

The Pamir region is located on the Tajikistan–Kyrgyzstan border, an area with high seismic activity due to the collision between the Indian and Eurasian Plates. The earthquake data used in this study were obtained from recordings of the 8H and 9H seismometer networks operated by the GeoForschungsZentrum (GFZ), which were installed in the study area during the period from September 2015 to March 2016. The research stages included manual picking of P and S wave arrival times, determination of the initial hypocenter locations, relocation using the HypoDD software with the Double-Difference method, and fault structure interpretation based on the relocation results. This method improves the precision of hypocenter locations by comparing the travel-time differences of wave arrivals between neighboring earthquake pairs thereby reducing the influence of uncertainties in the velocity model. The initial localization results show that earthquakes occurred a cross the Pamir region, with shallow to intermediate depths. After the second relocation stage, the earthquakes formed clearer lineation patterns consistent with the orientation of regional geological structures. The post-relocation distribution indicates the presence of active subsurface fault zones. In addition to confirming the relationship with major faults such as the Main Pamir Thrust and the Sarez–Karakul Fault, the spatial analysis also reveals earthquake clusters that suggest the existence of new faults in the Alichur area of eastern Tajikistan, specifically within the Gorno-Badakhshan Autonomous Region (GBAO) in the Pamir Plateau. The presence of these unconfirmed fault zones indicates that the tectonic dynamics of the Pamir region still hold complexities that have not yet been fully revealed. Keywords: Pamir, Earthquake Relocation, Double-Difference, Active Fault, Unidentified Fault