Analisis Kuantitatif Pengaruh Massa Dan Ketinggian Beban Weight-Drop Terhadap Kualitas Dan Karakteristik Sinyal Seismik Dangkal

Magnaliady, Naufal Maalikul Mulky (2026) Analisis Kuantitatif Pengaruh Massa Dan Ketinggian Beban Weight-Drop Terhadap Kualitas Dan Karakteristik Sinyal Seismik Dangkal. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Survei seismik dangkal memerlukan sumber getaran yang mampu menghasilkan data berkualitas tinggi dengan biaya, keselamatan, dan dampak lingkungan yang terkendali, sehingga sistem weight-drop banyak digunakan karena bersifat portabel, murah, dan berulang. Kualitas sinyal seismik yang dihasilkan weight-drop, khususnya amplitudo, kandungan frekuensi, dan kedalaman penetrasi, dikendalikan oleh dua parameter operasional utama, yaitu massa beban dan ketinggian jatuh, namun kajian sistematis mengenai pengaruh variasi kedua parameter tersebut terhadap kualitas sinyal masih terbatas, terutama pada kondisi geologi lokal Indonesia. Penelitian ini bertujuan menganalisis pengaruh variasi massa dan ketinggian beban weight-drop terhadap kualitas sinyal berdasarkan amplitudo puncak dan Signal-to-Noise Ratio, serta menganalisis kemiripan bentuk waveform antar kombinasi parameter sumber menggunakan analisis korelasi silang. Akuisisii data dilakukan di dua lokasi, yaitu Kecamatan Wringinanom, Kabupaten Gresik dan Taman Alumni ITS, Kecamatan Sukolilo, Surabaya, menggunakan seismograf GEOSAM 24 kanal dengan sembilan kombinasi variasi massa 15, 25, dan 30 kg dan ketinggian jatuh 1, 2, dan 3 m. Pengolahan data dilakukan menggunakan Jupyter Python meliputi koreksi gain, bandpass filtering, ekstraksi amplitudo puncak melalui envelope Hilbert, perhitungan SNR, regresi linear dan koefisien korelasi Pearson terhadap momentum tumbukan, serta korelasi silang ternormalisasi dengan trace referensi yang dipilih melalui metode medoid. Hasil penelitian menunjukkan momentum tumbukan berkorelasi positif terhadap amplitudo puncak dengan koefisien korelasi tertinggi mencapai 0,93 hingga 0,94 pada offset menengah, dan konfigurasi massa 25 kg secara konsisten memberikan transfer energi paling optimal pada kedua lokasi. Model peluruhan amplitudo menghasilkan koefisien atenuasi rata-rata sebesar 0,1271 per meter di Wringinanom dan 0,1408 per meter di Surabaya. Seluruh konfigurasi menghasilkan SNR di atas ambang batas 6 dB, sedangkan nilai korelasi silang yang tetap tinggi pada seluruh rentang momentum, berkisar antara 0,529 hingga 0,988, menunjukkan bentuk gelombang relatif stabil dalam batas elastisitas medium, meskipun pola keterulangannya bergantung pada karakteristik derau masing-masing lokasi.
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Shallow seismic surveys require a vibration source that produces high-quality data at controlled cost, safety, and environmental impact, making the weight-drop system widely used for being portable, inexpensive, and repeatable. The quality of weight-drop seismic signals, particularly amplitude, frequency content, and penetration depth, is controlled by two main parameters, the drop mass and drop height, yet systematic studies on their effect on signal quality remain limited, especially under local Indonesian geological conditions. This study analyzes the effect of weight-drop mass and height variation on signal quality based on peak amplitude and Signal-to-Noise Ratio, and analyzes waveform similarity among source parameter combinations using cross-correlation analysis. Data were acquired at two locations, Wringinanom District, Gresik Regency, and Taman Alumni ITS, Sukolilo District, Surabaya, using a 24-channel GEOSAM seismograph with nine combinations of mass 15, 25, and 30 kg and drop height 1, 2, and 3 m. Data processing in Jupyter Python included gain correction, bandpass filtering, peak amplitude extraction via Hilbert envelope, SNR calculation, linear regression and Pearson correlation against impact momentum, and normalized cross-correlation with a reference trace selected through the medoid method. The results show that impact momentum is positively correlated with peak amplitude, with the correlation coefficient reaching 0.93 to 0.94 at the mid offset, and the 25 kg mass configuration consistently gave the most optimal energy transfer at both locations. The amplitude decay model yielded average attenuation coefficients of 0.1271 per meter at Wringinanom and 0.1408 per meter at Surabaya. All configurations produced SNR above the 6 dB threshold, while cross-correlation values remained consistently high across the momentum range, ranging from 0.529 to 0.988, indicating that waveform shape remained stable within the medium's elastic limit, although repeatability depended on the noise characteristics of each location.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Amplitudo, Signal-to-Noise Ratio, Waveform, Weight-drop, Momentum, Amplitude, Signal-to-Noise Ratio, Waveform, weight-drop, Momentum
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:	Naufal Maalikul Mulky Magnaliady
Date Deposited:	22 Jul 2026 01:21
Last Modified:	22 Jul 2026 01:21
URI:	http://repository.its.ac.id/id/eprint/135925

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