Electronic Theses and Dissertation

Kawasan manifestasi panas bumi Ie Seu'um di kaki utara Gunung Seulawah Agam, Aceh Besar, menunjukkan aktivitas hidrotermal aktif berupa mata air panas dan fumarol yang dikontrol oleh sistem Sesar Seulimeum. Penelitian ini bertujuan mengidentifikasi pola reflektor gelombang seismik, memetakan struktur lapisan bawah permukaan, dan menginterpretasi keberadaan struktur rekahan yang berpotensi menjadi jalur migrasi fluida hidrotermal menggunakan metode seismik refleksi. Akuisisi data dilakukan pada empat lintasan dengan sumber getar Vibrator Seismik Elvis VII dan 24 geophone. Data mentah format SEG-2 diolah menggunakan perangkat lunak RadExPro melalui tahapan kontrol kualitas geometri, analisis medan gelombang, muting, analisis kecepatan, koreksi Normal Moveout (NMO), stacking, dan migrasi, kemudian diinterpretasi di Petrel 2020 melalui picking horizon dan picking fault. Hasil pengolahan menghasilkan penampang kedalaman dengan satu hingga tiga horizon menerus pada kedalaman 8-66 m. Struktur bawah permukaan tersusun atas zona lapuk-retak/aluvium di bagian dangkal yang menutupi satuan vulkanik Lam Teuba (QTvt). Lintasan 2, yang berada tepat di atas titik kemunculan air panas, menunjukkan dua rekahan utama dengan pergeseran horizon yang jelas dan anomali amplitudo tinggi, diinterpretasikan sebagai jalur aliran naik (upflow channel) fluida hidrotermal. Sebaliknya, Lintasan 1 tidak menunjukkan rekahan signifikan, sementara Lintasan 3 dan 4 di luar zona manifestasi tetap menunjukkan indikasi rekahan minor, menandakan pengaruh Sistem Patahan Seulimeum meluas melampaui titik manifestasi permukaan. Temuan ini menegaskan bahwa metode seismik refleksi efektif untuk mendelineasi struktur rekahan dangkal di lingkungan vulkanik.
Kata kunci: seismik refleksi, panas bumi, Ie Seu'um, rekahan, upflow channel, Sesar Seulimeum

The Ie Seu'um geothermal manifestation area, located at the northern foot of Mount Seulawah Agam, Aceh Besar, exhibits active hydrothermal activity in the form of hot springs and fumaroles controlled by the Seulimeum Fault System. This study aims to identify seismic wave reflector patterns, map the subsurface layer structure, and interpret the presence of fracture structures that potentially serve as hydrothermal fluid migration pathways using the seismic reflection method. Data acquisition was carried out along four survey lines using an Elvis VII Vibroseis source and 24 geophones. Raw data in SEG-2 format were processed using RadExPro software through stages of geometry quality control, wavefield analysis, muting, velocity analysis, Normal Moveout (NMO) correction, stacking, and migration, followed by interpretation in Petrel 2020 through horizon and fault picking. The processing results produced depth sections with one to three continuous horizons at depths of 8-66 m. The subsurface structure consists of a shallow weathered-fractured/alluvium zone overlying the Lam Teuba volcanic unit (QTvt). Line 2, located directly above the hot spring emergence point, shows two major fractures with clear horizon offsets and high-amplitude anomalies, interpreted as an upflow channel for hydrothermal fluid. In contrast, Line 1 shows no significant fractures, while Lines 3 and 4, located outside the manifestation zone, still exhibit indications of minor fractures, suggesting that the influence of the Seulimeum Fault System extends beyond the surface manifestation point. These findings confirm that the seismic reflection method is effective for delineating shallow fracture structures in volcanic environments. Keywords: seismic reflection, geothermal, Ie Seu'um, fractures, upflow channel, Seulimeum Fault