Mala, HartiUmbu (2015) Kajian Mikrotremor dan Geolistrik Resistivitas di Sekitar Jalan Arteri Primer Trans Timor, Desa Oebelo Kabupaten Kupang-NTT untuk Mitigasi Bencana. Magister thesis, Universitas Brawijaya.
Abstract
Telah dilakukan penelitian kajian mikrotremor dan geolistrik resistivitas di sekitar jalan arteri primer trans Timor untuk mitigasi bencana dan desain infrastruktur. Tujuan dari penelitian ini adalah mendapatkan nilai percepatan tanah maksimum, frekuensi dominan tanah, indeks kerentanan seismik dan pendugaan ketebalan lapisan sedimen.Pengambilan data mikrotremor menggunakan Seismometer tiga komponen tipe DS-4A feedback short-period seismometer pada 52 titik ukur dengan jarak antar titik 250 m. Nilai frekuensi dominan tanah dan faktor amplifikasi diperoleh dengan metode analisis kurva Horizontal to vertical spectral rasio (HVSR). Kedua parameter ini digunakan untuk perhitungan Indeks kerentanan seismik. Perhitungan nilai percepatan tanah maksimum menggunakan persamaan empiris Kanai, data periode dominan tanah diperoleh dari hasil konversi nilai frekuensi sedangkan parameter-parameter gempa berdasarkan kejadian gempa 50 tahun dari tahun 1963-2013 dengan magnitudo ≥ 3. Pengukuran geolistrik menggunakan Resistivitimeter OYO, dengan susunan eletroda berdasarkan konfigurasi Wenner-Schlumberger, terbagidalam dua lintasan pengukuran, dengan panjang masing-masing lintasan 400 m.Hasil penelitian menunjukkan bahwa nilai percepatan tanah maksimum berkisar antara 80 gal-503,08 gal dengan tingkat resiko sedang dua sampai tingkat resiko sangat besar satu. Sebaran nilai frekuensi dominan tanah adalah 0,62 Hz-18,27 Hz dengan rata-rata 3,90 Hz, sementara distribusi indeks kerentanan seismik berada pada rentang 0,21 dan 21,83 dengan rata-rata 4,40. Jenis tanah didominasi aluvium dan clay sebagai lapisan penutup (top soil) dengan variasi ketebalan dari 10 m sampai 50 m, kemudian ditopang oleh batuan gamping sebagai batuan dasar (bedrock).
English Abstract
A research on microtremor and geoelectric resistivity around Trans Timor Primary Artery Road to disaster mitigation and infrastructure design, has been done. The aims of this research were to obtain the Peak Ground Acceleration (PGA) value, the soil dominant frequency, seismic vulnerability index and to estimate the thickness of sediment layer.Microtremor data collection was done by using a three-component seismometer, DS-4A feedback short-period, at 52 points with 250 m interval. Dominant frequency and amplification factors were obtained by using curve analysis method, horizontal to vertical spectral ratio (HVSR). Both of these parameters were used to calculate the seismic vulnerability index. The PGA value was calculated using Kanai empirical equations, where the data of dominant period were obtained from the inversion of frequency values while the parameters of the earthquake were based on seismic events in the last 50 years, from 1963 to 2013 with magnitude of ≥ 3. Geoelectric measurements were conducted using a Resistivitymeter OYO, based on Wenner-Schlumberger configuration and it was divided into two lines, with length of 400 m each.The results showed that the PGA value is ranged between 80 and 503.08 gal with risk level of moderate two, to very high risk level one. The distribution value of the soil dominant frequency was 0.62 Hz-18.27 Hz, while the distribution of the seismic vulnerability index ranged from 0.21 to 21.83. The type of soil is dominated by clay and alluvium as top soil and its thickness variation was 10 m to 50 m, and was supported by limestone as bedrock.
| Item Type: | Thesis (Magister) |
|---|---|
| Identification Number: | TES/550/MAL/k/041500581 |
| Subjects: | 500 Natural sciences and mathematics > 550 Earth sciences |
| Divisions: | S2/S3 > Magister Fisika, Fakultas MIPA |
| Depositing User: | Samsul Arifin |
| Date Deposited: | 27 Mar 2015 15:36 |
| Last Modified: | 27 Mar 2015 15:36 |
| URI: | http://repository.ub.ac.id/id/eprint/157575 |
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