ABSTRAKTelah dilakukan pengolahan dan interpretasi data seismik 2D dengan menggunakan informasi line BGR06-141 untuk mengidentifikasi kondisi geologi subsurface pada zona epicentral gempa megathrust tahun 2004. Data seismik tersebut merupakan bagian dari daerah subduksi Lempeng Samudera Indo-Australia dan Benua Eurasia yang memiliki seismisitas yang tinggi dan rawan terhadap gempa. Pengolahan data seismik dilakukan dari proses preconditioning, radon filter, analisis kecepatan dan Post Stack Time Migration untuk meningkatkan signal to noise ratio(S/N ratio). Hasil pengolahan berupa penampang seismik yang menggambarkan kondisi geologi bawah permukaan daerah penelitian. Interpretasi yang berhasil dilakukan berupa sedimen sebagai cekungan busur muka (fore arc basin), tinggian (ridge), dan prisma akresi. Hasil penelitian juga menunjukkan patahan aktif strike slip fault, normal fault dan reverse fault pada penampang seismik yang diperkuat dengan penerapan atribut seismic variance. Diharapkan hasil bisa dimanfaatkan sebagai informasi awal mengenai kegempaan dimasa datang.

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ABSTRACTA 2D seismic data processing and interpretation of line BGR06-141 have been done for identifying geological subsurface condition around epicentral zone of 2004 megathrust earthquake. The seismic data is acquired crossing the subduction zones between Indo-Australian Oceanic Plate and the Eurasian Continent Plate where has a high seismicity and vulnerable against earthquakes. Several data processing has been performed systematically on the seismic including pre-conditioning data, filtering using radon transform, velocity analysis and Post Stack Time Migration to improve enhance the signal to noise ratio (S/N ratio). Data processing results is shown in the form of vertical seismic section that describes the subsurface geological condition in the study. Careful interpretation of data processing result shows that the form of fore arc basin sediments, ridge and a prism accretion. This study also shows active strike slip fault, normal fault and reverse fault on the vertical seismic section which are confirmed by seismic attribute variance. We hope this result could be a reference for early information about future earthquake study.