Aplikasi dan Pemodelan Seismik Interferometri

Muhammad, Nur Rochman (2017) Aplikasi dan Pemodelan Seismik Interferometri. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Seismik interferometri memanfaatkan ambient noise sebagai sumber informasi sub-surface dalam pengolahan data. Oleh karena itu seismik interferometri termasuk kedalam kategori seismik pasif karena tanpa menggunakan sumber buatan dalam akusisi data. Tahapan pemodelan dilakukan sebagai media pengujian atau validasi sintetik pengolahan seismik interferometri. Model yang digunakan berbeda antara pengolahan data seismik refleksi dengan seismik tomografi. Metoda cross-correlation digunakan untuk mendapatkan Green’s function yang dikenal sebagai virtual source. Alat yang digunakan akusisi data lapangan adalah 24-Recheiver geophone dengan spasi 4 meter antar recheiver. Lama perekaman data lapangan adalah 99.99 detik dengan sampling time 4 milidetik. Pengambilan data seismik interferometri lapangan dengan kondisi traffic noise yang berbeda. Hal tersebut bertujuan untuk melihat perbedaan karakteristik dari dua virtual-source dengan kondisi traffic noise yang berbeda pada hasil dari pengolahannya. Hasil dari pengolahan seismik interferometri adalah penampang Vp dan penampang refleksi. Setelah dilakukan analisa kualitas virtual-source yang lebih baik didapatkan pada kondisi low traffic atau kondisi minim noise permukaan. Regresi logaritmik Penampang Vp seismik tomografi aktif dengan Vp seismik interferometri dilakukan untuk mempermudah interpretasi hasil seismik tomografi interferometri. Penampang yang telah didapatkan kemudian dilakukan interpretasi sederhana berdasarkan informasi geologi regional dimana daerah penelitian memiliki litologi Alluvium. Intepretasi seismik refleksi interferometri bawah permukaan area pengukuran didapatkan tiga reflektor pada kedalaman 150 m dengan tebal perlapisan antara 40-50 m. Tiga perlapisan didefinisikan dari intepretasi seismik tomografi interferometri yaitu Top soil dengan tebal 3 m – 8m, kemudian Clay kompaksi rendah 1.5 m – 2 m, kemudian lapisan terakhir adalah Clay kompaksi sedang-tinggi. ===================================================================== Seismic interferometry utilises ambient noise as a source of sub-surface information in data processing. Therefore seismic interferometry belongs to the passive seismic category because without using artificial sources in data acquisition. The modelling stage is performed as a test medium or synthetic validation of seismic interferometry processing. The model used varies between seismic reflection data processing with tomographic seismic. The cross-correlation method is used to get Green's function known as the virtual source. The tool used for field data acquisition is 24-Recheiver geophone with a space of 4 meters between receiver. Duration of field data recording is 99.99 seconds with 4 millisecond sampling time. Segment retrieval of field interferometry data with different traffic noise conditions. It aims to look at the different characteristics of two virtual-sources with different traffic noise conditions on the results of the processing. The result of interferometric seismic processing is the cross section of Vp and the reflection cross section. After analysing the quality of virtual-source is better found in low traffic conditions or minimal surface noise conditions. Logarithmic regression A cross section of active tomographic seismic Vp with interferometric seismic Vp is performed to facilitate interpretation of interferometric tomographic seismic results. The obtained cross section is then made the simple interpretation based on regional geological information where the research area has Alluvium lithology. Interpretometric reflection seismic reflections beneath the surface of the measurement area obtained three reflectors at a depth of 150 m with a thick layer between 40-50 m. Three layers were defined from interferometric tomography seismic interpretation ie Top soil with 3 m - 8m thick, then Clay compact low 1.5 m - 2 m, then the last layer was medium - high Clay compaction.

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: seismik interferometri, validasi, low traffic noise, Green’s function, interpretasi.
Subjects: Q Science > QE Geology > QE601 Geology, Structural
Divisions: Faculty of Civil Engineering and Planning > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User: Nur Rochman Muhammad
Date Deposited: 22 Sep 2017 06:35
Last Modified: 06 Mar 2019 02:49
URI: http://repository.its.ac.id/id/eprint/43618

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