Analisis Komparatif Sumber Seismik Dengan Menggunakan Weight Drop Dan Hammer Secara Kuantitatif

Aufa, Muhammad Ghatfan (2026) Analisis Komparatif Sumber Seismik Dengan Menggunakan Weight Drop Dan Hammer Secara Kuantitatif. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penelitian ini bertujuan untuk menganalisis dan membandingkan performa dua sumber energi seismik impulsif, yaitu Weight Drop dan Hammer, secara kuantitatif pada survei seismik dangkal dengan medium yang sama. Akuisisi data dilakukan di Kecamatan Wringinanom, Kabupaten Gresik, Jawa Timur, menggunakan konfigurasi split-spread dengan panjang lintasan 48 meter dan interval geophone 2 meter. Masing-masing sumber direkam sebanyak lima kali pengulangan shot untuk mengevaluasi karakteristik sinyal dan tingkat repeatability. Analisis dilakukan terhadap beberapa parameter utama, meliputi instantaneous amplitude, amplitude spectrum, relative energy ratio (RER), signal-to-noise ratio (S/N), repeatability, faktor kualitas seismik (Q), atenuasi, dan depth of penetration (DOP). Pengolahan data meliputi proses vertical stacking, transformasi Hilbert untuk analisis envelope amplitudo, Fast Fourier Transform (FFT) untuk analisis spektrum frekuensi, serta metode spectral ratio untuk estimasi faktor kualitas seismik (Q). Hasil penelitian menunjukkan bahwa Weight Drop menghasilkan amplitudo sinyal yang lebih besar, rasio energi relatif yang lebih tinggi, serta nilai signal-to-noise ratio (S/N) yang lebih baik dibandingkan Hammer. Analisis spektrum frekuensi menunjukkan bahwa Weight Drop memiliki frekuensi dominan sekitar 16 Hz, sedangkan Hammer memiliki frekuensi dominan sekitar 28 Hz. Dominasi frekuensi rendah pada Weight Drop menyebabkan energi gelombang lebih mampu dipertahankan selama propagasi sehingga menghasilkan kemampuan penetrasi yang lebih baik. Evaluasi repeatability menunjukkan bahwa Weight Drop memiliki konsistensi waveform antar-shot yang lebih tinggi dibandingkan Hammer. Analisis atenuasi dan faktor kualitas seismik menunjukkan bahwa kedua sumber mengalami pelemahan energi pada medium penelitian yang memiliki karakteristik atenuatif, namun energi Weight Drop cenderung lebih mampu bertahan pada offset yang lebih jauh dibandingkan Hammer akibat kandungan frekuensi dominannya yang lebih rendah. Estimasi depth of penetration (DOP) menunjukkan bahwa Weight Drop memiliki kemampuan penetrasi sekitar 2 kali lebih dalam dengan kedalaman investigasi teoritis mencapai sekitar 26.25 meter, sedangkan Hammer terbatas pada kisaran kurang dari 11.7 meter. Berdasarkan hasil analisis kuantitatif, Weight Drop lebih efektif digunakan untuk survei yang memerlukan penetrasi lebih dalam, kualitas sinyal yang tinggi, dan repeatability yang baik. Sebaliknya, Hammer lebih sesuai untuk investigasi dangkal yang membutuhkan resolusi relatif tinggi, mobilisasi cepat, dan efisiensi operasional. Hasil penelitian ini menunjukkan bahwa parameter amplitudo, frekuensi dominan, rasio energi relatif, signal-to-noise ratio (S/N), repeatability, faktor kualitas seismik (Q), atenuasi, dan depth of penetration (DOP) dapat digunakan sebagai indikator kuantitatif dalam pemilihan sumber seismik yang sesuai dengan tujuan survei dan karakteristik medium bawah permukaan.
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This study aims to quantitatively analyze and compare the performance of two impulsive seismic energy sources, namely Weight Drop and Hammer, in a shallow seismic survey conducted over the same subsurface medium. Data acquisition was carried out in Wringinanom District, Gresik Regency, East Java, Indonesia, using a split-spread configuration with a 48-meter survey line and a 2-meter geophone interval. Each source was recorded through five repeated shots to evaluate signal characteristics and repeatability. The analysis focused on several key parameters, including instantaneous amplitude, amplitude spectrum, relative energy ratio (RER), signal-to-noise ratio (S/N), repeatability, seismic quality factor (Q), attenuation, and depth of penetration (DOP). Data processing involved vertical stacking, Hilbert transform for envelope amplitude analysis, Fast Fourier Transform (FFT) for frequency spectrum analysis, and the spectral ratio method for estimating the seismic quality factor (Q). The results indicate that the Weight Drop source produces higher signal amplitudes, a greater relative energy ratio, and better signal-to-noise ratio (S/N) values than the Hammer source. Frequency spectrum analysis shows that the Weight Drop has a dominant frequency of approximately 16 Hz, whereas the Hammer exhibits a higher dominant frequency of approximately 28 Hz. The lower-frequency dominance of the Weight Drop allows seismic energy to be preserved more effectively during wave propagation, resulting in superior penetration capability. Repeatability evaluation demonstrates that the Weight Drop provides higher waveform consistency between repeated shots compared to the Hammer. Attenuation and seismic quality factor analyses reveal that both sources experience energy loss within the study area, which is characterized by an attenuative medium; however, the Weight Drop energy tends to be maintained over longer offsets than the Hammer due to its lower dominant frequency content. Depth of penetration (DOP) estimation shows that the Weight Drop achieves approximately 2 times greater penetration depth, with a theoretical investigation depth of about 26.25 meters, whereas the Hammer is limited to less than 11.7 meters. Based on the quantitative analysis, the Weight Drop is more effective for surveys requiring deeper penetration, high signal quality, and strong repeatability. In contrast, the Hammer is more suitable for shallow investigations that require relatively high resolution, rapid deployment, and operational efficiency. The findings demonstrate that amplitude, dominant frequency, relative energy ratio, signal-to-noise ratio (S/N), repeatability, seismic quality factor (Q), attenuation, and depth of penetration (DOP) can serve as quantitative indicators for selecting an appropriate seismic source according to survey objectives and subsurface medium characteristics.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Seismik Dangkal, Weight Drop, Hammer
Subjects:	Q Science > QE Geology > QE538.5 Seismic tomography; Seismic waves. Elastic waves
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User:	M. Ghatfan Aufa
Date Deposited:	24 Jul 2026 02:40
Last Modified:	24 Jul 2026 02:40
URI:	http://repository.its.ac.id/id/eprint/136566

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