Estimasi Kecepatan Gelombang Geser Bawah Permukaan Pada Lapisan Dangkal Menggunakan Data Mikrotremor di Daerah Mamboro

Indra, Indra; Efendi, Rustan; Abdullah, Abdullah

doi:10.22487/gravitasi.v17i2.12418

Cited by 3 publications

(3 citation statements)

References 1 publication

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“…Parameter Vs30 is the shear wave velocity or secondary wave velocity detected to a depth of 30 meters. The value of Vs30 can be used as an indicator for determining rock classification based on the strength of earthquake vibrations caused by local effects so it is needed for planning earthquake-resistant building structures [18].…”

Section: Hvsr Inversion Methodsmentioning

confidence: 99%

Seismic microzonation for Lembang fault hazard area in West Bandung Regency based on microtremor measurement

Arrahman,

Tohari,

Perwita

2023

IOP Conf. Ser.: Earth Environ. Sci.

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Lembang district in Bandung Regency is prone to seismic risk because it is in the vicinity of a very well-known active fault called the Lembang Fault. The effort to reduce the seismic risk requires knowledge of the dynamic properties of the soils, mainly derived from young volcanic rocks. This paper presents the results of a seismic microzonation study based on microtremor measurements. In total 195 microtremor data from single-station measurements were processed using the HVSR method to estimate the dominant frequency and amplification factors. Furthermore, the Rayleigh wave ellipticity inversion has also been used to estimate the corresponding Vs profiles. The HVSR results show that the dominant frequency for the Lembang District is 0.2 Hz or higher, and the amplification factors are dominantly higher than 3. Some areas also have a lower dominant frequency than 2 Hz, especially the area with thick soft sediments. Results of the inversion show that the shear wave velocities of subsoil layers for the upper 30 m vary from 250 m/s to 300 m/s, indicating site class D. Meanwhile, the areas with Vs30 less than 250 m/s are especially located north of the Lembang Fault. Thus, the area is likely to have a stronger ground response to earthquake shaking than the other areas in Lembang District.

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Section: Hvsr Inversion Methodsmentioning

confidence: 99%

Seismic microzonation for Lembang fault hazard area in West Bandung Regency based on microtremor measurement

Arrahman,

Tohari,

Perwita

2023

IOP Conf. Ser.: Earth Environ. Sci.

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“…Vs30 banyak digunakan untuk mengidentifikasi karakteristik struktur tanah hingga kedalam 30 m dari permukaan. Kedalaman tersebut ditetapkan dengan anggapan hanya lapisan-lapisan batuan sampai kedalaman 30 meter saja yang menentukan pembesaran gelombang gempa (Indra, Efendi and Abdullah, 2019). Penentuan kecepatan gelombang geser dapat dilakukan dengan beberapa metode mulai pengeboran secara langsung di lapangan sampai dengan pendekatan empiris.…”

Section: Penentuan Kelas Situsunclassified

Pengembangan Peta Spektra Percepatan Peta Kategori Desain Seismik Provinsi Daerah Istimewa Yogyakarta

Saputra

2023

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Abstrak Indonesia dikelilingi oleh empat lempeng besar dunia yang bergerak secara konvergen sehingga menyebabkan sering mengalami kejadian gempa. Salah satu upaya mengurangi risiko bencana gempa adalah melakukan upaya mitigasi seperti pembuatan peta bahaya gempa. Penyusunan Peta Kategori Desain Seismik (KDS) Indonesia saat ini masih terkendala karena keterbatasan data penyelidikan tanah. Meskipun demikian, problem tersebut dapat diatasi dengan melakukan pendekatan berdasarkan data kecepatan gelombang geser pada kedalaman 30 (Vs30) yang disediakan oleh (USGS, 2020). Tujuan dari penelitian ini adalah melakukan penyusunan Peta Kategori Desain Seismik untuk Provinsi Daerah Istimewa Yogyakarta (DIY). Tahapan penelitian diawali dengan pengumpulan data, perhitungan percepatan tanah dan penentuan kategori desain seismik untuk setiap titik dari 3759 titik tinjauan. Hasil penyusunan peta kategori desain seismik Daerah Istimewa Yogyakarta pada kategori risiko I, II, dan III menunjukkan hasil Kabupaten Bantul, Kota Yogyakarta masuk dalam kategori risiko tinggi (KDS D), sedangkan Kabupaten Sleman, Kabupaten Kulonprogo, dan Kabupaten Gunung Kidul masuk dalam kategori risiko sedang hingga tinggi (B, C, dan D). Kategori desain seismik pada kategori risiko IV hampir secara keseluruhan kabupaten-kabupaten di Provinsi Daerah Istimewa Yogyakarta masuk dalam Kategori Desain Seismik D yang artinya memiliki tingkat risiko gempa bumi yang tinggi. Kata kunci: Gempa, mitigasi, kecepatan gelombang geser, kategori desain seismik Abstract Indonesia is surrounded by four large plates of the world that move convergently, causing frequent earthquakes. One of the efforts to reduce the risk of earthquake disasters is to carry out mitigation efforts such as making earthquake hazard maps. The compilation of Indonesia's Seismic Design Category Map is currently still hampered due to limited soil investigation data. However, this problem can be overcome by making an approach based on the shear wave velocity data (Vs30) provided by (USGS, 2020). The purpose of this research is to create a Seismic Design Category Map for the Province of the Special Region of Yogyakarta. The research phase begins with collecting data, calculating ground acceleration, and determining the seismic design category for each point of the 3759 review points. The compilation result of seismic design category maps for the Special Region of Yogyakarta in risk categories I, II, and III showed that Bantul Regency, Yogyakarta City were in the high risk category (KDS D), while Sleman Regency, Kulonprogo, and Gunung Kidul fall into the moderate to high-risk category (B, C, and D). The Seismic Design Category Map for risk category IV showed that almost all districts in the Special Region of Yogyakarta Province were Seismic Design Category D, which means it has a high level of earthquake risk. Keywords: Earthquake, mitigation, shear wave velocity, seismic design categories

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“…Gelombang seismik merupakan gelombang yang ditimbulkan dari energi yang dilepaskan ketika lempeng bumi tidak dapat lagi menahan akumulasi energi saat terjadinya benturan lempeng tektonik bumi, aktifitas magma gunung api maupun kejadian lain secara sengaja maupun tidak sengaja. Gelombang seismik dapat menjalar di dalam bumi maupun di permukaan bumi [6]. Gelombang seismik yang menjalar di dalam bumi disebut gelombang badan (body wave) sedangkan gelombang seismik yang menjalar di permukaan bumi disebut sebagai gelombang permukaan (surface wave) [7].…”

Section: Gelombang Seismikunclassified

Earthquake Hypocenter Relocation in The Abang-Culik Fault, Karangasem using Coupled Velocity-Hypocenter Method

Yudistira

Sukarasa

Astra³

2021

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Research has been done about the relocation of earthquake hypocenter position, seismic wave local velocity and correction of seismic wave recording station at the Abang-Culik Fault area according to coordinate 115,25°-115,75° BT and 8,00°-8,60° LS. Data which was used on this research was the earthquake data that occur in the 2015-2020 period. The research was conducted using the coupled velocity-hypocenter method. From the relocation result, the position of the earthquake hypocenter shifted, which initially spread to become more concentrated in the fault plane area. The local velocity decreasing a lot in the 3rd layer which was influenced by the presence of the Mount Agung magma pocket in that area. The correction of Station shown that only 1 station has a negative value of delay time, namely IGBI station while the other 13 stations show a positive value of delay time.

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Estimasi Kecepatan Gelombang Geser Bawah Permukaan Pada Lapisan Dangkal Menggunakan Data Mikrotremor di Daerah Mamboro

Cited by 3 publications

References 1 publication

Seismic microzonation for Lembang fault hazard area in West Bandung Regency based on microtremor measurement

Seismic microzonation for Lembang fault hazard area in West Bandung Regency based on microtremor measurement

Pengembangan Peta Spektra Percepatan Peta Kategori Desain Seismik Provinsi Daerah Istimewa Yogyakarta

Earthquake Hypocenter Relocation in The Abang-Culik Fault, Karangasem using Coupled Velocity-Hypocenter Method

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