Ramadhan, Djody Virgiawan (2021) Analisis Data Mikrotremor Dengan Metode Horizontal Vertical Spectral To Ratio (HVSR) Untuk Mikrozonasi Kegempaan Daerah Gondang Kabupaten Bojonegoro. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Berdasarkan data tahun 2016, daerah Gondang, Kabupaten Bojonegoro pernah mengalami gempa dengan intensitas yang tinggi. Ini tidak terlepas dari keberadaan struktur kompleks Zona Kendeng. Salah satu metode geofisika yang bisa digunakan untuk memetakan potensi bencana gempa bumi di daerah Gondang adalah Mikrotremor. Mikrotremor merupakan metode yang murah dan mudah, sehingga baik digunakan sebagai awal dari studi kebencanaan di dareah Gondang. Penelitian ini bertujuan untuk mengetahui mikrozonasi kegempaan dan karakteristik tanah di daerah Gondang, Kabupaten Bojonegoro. Data yang digunakan adalah data pengukuran Mikrotremor, data gempa (magnitudo dan hiposenter), dan Vs30. Data kemudian diolah menggunakan metode HVSR (Horizontal Vertical Spectral To Ratio) hingga menghasilkan parameter frekuensi dominan (f0), faktor amplitudo (A0), indeks kerentanan seismik (Kg), ketebalan sedimen (H), Peak Ground Acceleration (α), dan ground shear-strain (γ). Digunakan juga metode fuzzy c-means clustering dengan mengintegrasikan beberapa parameter untuk memperdalam analisis. Parameter-parameter tersebut kemudian dipetakan, dianalisis, dan dikorelasikan dengan geologi regional daerah Gondang untuk mengestimasi kondisi sesungguhnya. Berdasarkan hasil penelitian, didapatkan bahwa mayoritas tanah di daerah Gondang adalah tanah Tipe III B dengan ketebalan sekitar 15-35m. nilai Kg rendah (<5) mengindikasikan tanah di daerah Gondang memiliki karakter yang keras dan kompak. Di barat Gondang terkonsentrasi nilai faktor amplitudo sedang ke sangat tinggi (>3) dan ini berkorelasi dengan adanya perselingan beberapa formasi secara horizontal. Selain itu, analisis Kg dan γ juga menunjukkan bahwa sebagian besar daerah Gondang, khususnya di barat berpotensi terjadinya retakan dan penurunan tanah ketika terjadi gempa (Kg > 5 dan γ ≥ 1 x 10-4). Dari analisis nilai PGA, daerah Gondang berada di skala SIG BMKG II. Artinya, bila terjadi gempa bumi, maka getaran gempanya akan terasa tetapi tidak menimbulkan kerusakan. Dari analisis fuzzy c-means clustering, diketahui bahwa secara keseluruhan daerah Gondang, Kabupaten Bojonegoro didominasi oleh zona bahaya rendah.
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Based on 2016 data, the Gondang area, Bojonegoro Regency has experienced an earthquake with a high intensity. This is inseparable from the existence of the complex structure of the Kendeng Zone. One of the geophysical methods that can be used to map potential earthquake disasters in the Gondang area is Mikrotremor. Microtremor is a cheap and easy method, so it is good to use it as a starting point for disaster studies in the Gondang area. This study aims to determine the seismic microzonation and soil characteristics in the Gondang area, Bojonegoro Regency. The data used are microtremor measurement data, earthquake data (magnitude and hypocenter), and Vs30. The data is then processed using the HVSR (Horizontal Vertical Spectral To Ratio) method to produce dominant frequency parameters (f0), amplitude factor (A0), seismic vulnerability index (Kg), sediment thickness (H), Peak Ground Acceleration (α), and ground shear-strain (γ). The fuzzy c-means clustering method is also used by integrating several parameters to deepen the analysis. These parameters are then mapped, analyzed, and correlated with the regional geology of the Gondang area to estimate the actual conditions. Based on the results of the study, it was found that the majority of the soil in the Gondang area was Type III B soil with a thickness of about 15-35m. a low Kg value (<5) indicates that the soil in the Gondang area has a hard and compact character. In the west of Gondang, the value of the amplitude factor is moderate to very high (>3) and this is correlated with the presence of several horizontal formations. In addition, the analysis of Kg and γ also shows that most of the Gondang area, especially in the west, has the potential for cracks and land subsidence during an earthquake (Kg > 5 and γ ≥ 1 x 10-4). From the analysis of the PGA value, the Gondang area is on the BMKG II GIS scale. That is, when an earthquake occurs, the vibrations of the earthquake will be felt but not cause damage. From fuzzy c-means clustering analysis, it is known that the overall Gondang area, Bojonegoro Regency is dominated by low hazard zones.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Uncontrolled Keywords: | Gondang, HVSR, Kegempaan, Mikrotremor, Mikrozonasi, Seismicity, Microtremor, Microzonation |
| Subjects: | G Geography. Anthropology. Recreation > G Geography (General) > G70.212 ArcGIS. Geographic information systems. Q Science > QE Geology > QE538.5 Seismic tomography; Seismic waves. Elastic waves Q Science > QE Geology > QE538.8 Earthquakes. Seismology Q Science > QE Geology > QE539.2.S4 Seismic models Q Science > QE Geology > QE601 Geology, Structural Q Science > QE Geology > QE604 Deformation |
| Divisions: | Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis |
| Depositing User: | Djody Virgiawan Ramadhan |
| Date Deposited: | 29 Aug 2021 18:13 |
| Last Modified: | 07 Nov 2024 05:01 |
| URI: | http://repository.its.ac.id/id/eprint/90515 |
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