Local site effects and seismic microzonation around Suban Area, Curup Rejang Lebong, Bengkulu deduced by ambient noise measurements

IF 3.8 Q2 ENVIRONMENTAL SCIENCES

Geoenvironmental Disasters Pub Date : 2024-01-27 DOI:10.1186/s40677-024-00268-7

Brecya Isa Siburian, Marzuki Marzuki, Ashar Muda Lubis

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引用次数: 0

Abstract

The Suban area of Curup Rejang Lebong is a tourist region in Bengkulu Province, Indonesia, close to the active Ketaun and Musi faults, which are segments of the Sumatra Fault System (SFS). However, no studies have been conducted in this area to assess how geological structures affect seismic ground motions and contribute to seismic hazard and risk assessment. The first study of seismic microzonation in the Suban area of Curup City by ambient noise measurements was conducted at 100 sites, spaced ~ 1 km apart, with 60 min of data acquisition for each site. All microseismic data were processed using the Horizontal to Vertical Spectral Ratios (HVSR) method. The HVSR method revealed the amplification factors (A0) ranging from 1.23 to 8.26 times, corresponding to natural frequency (f0) variations between 1.24 and 9.67 Hz. About 13% and 55% of the sites show high (6 ≤ A0 ≤ 9) and medium (3 ≤ A0 ≤ 6) amplifications, respectively, predominantly in the western parts of the study area, consistent with a high seismic vulnerability index (Kg). Furthermore, we also estimated the ground shear strain (GSS) of the region using the Kanai method with two large historical earthquakes at the Ketahun segment in 1943 (Mw 7.4) and the Musi segment in 1979 (Mw 6.0). The Kg value is consistent with the GSS values and indicates areas of severe damage during the historic earthquakes. Thus, the western parts of the Suban region are vulnerable to severe damage from an earthquake. These findings could provide valuable insights for future planning and risk management efforts aimed at minimizing the impact of earthquakes in the Suban region.

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通过环境噪声测量推断明古鲁 Curup Rejang Lebong 苏班地区周围的局部场地效应和地震微区划

Curup Rejang Lebong 的苏班地区是印度尼西亚明古鲁省的一个旅游区，毗邻苏门答腊断层系统（SFS）的活跃断层 Ketaun 和 Musi。然而，该地区尚未开展任何研究来评估地质结构如何影响地震地面运动，以及如何促进地震灾害和风险评估。通过环境噪声测量对 Curup 市 Suban 地区地震微区划分的首次研究在 100 个站点进行，每个站点间隔约 1 公里，数据采集时间为 60 分钟。所有微地震数据均采用水平与垂直频谱比（HVSR）法进行处理。HVSR 方法显示放大系数 (A0) 在 1.23 至 8.26 倍之间，对应的固有频率 (f0) 变化在 1.24 至 9.67 Hz 之间。约 13% 和 55% 的地点分别显示出高（6 ≤ A0 ≤ 9）和中（3 ≤ A0 ≤ 6）放大系数，主要集中在研究区域的西部，这与高地震易损性指数（Kg）相一致。此外，我们还利用 1943 年 Ketahun 地段（Mw 7.4）和 1979 年 Musi 地段（Mw 6.0）的两次历史大地震，采用 Kanai 方法估算了该地区的地表剪切应变（GSS）。Kg 值与 GSS 值一致，表明在历史上的地震中受损严重的地区。因此，苏班地区西部容易受到地震的严重破坏。这些发现可为今后旨在最大限度减少地震对苏班地区影响的规划和风险管理工作提供有价值的见解。

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来源期刊

Geoenvironmental Disasters Social Sciences-Geography, Planning and Development

CiteScore

8.90

自引率

6.20%

发文量

期刊介绍： Geoenvironmental Disasters is an international journal with a focus on multi-disciplinary applied and fundamental research and the effects and impacts on infrastructure, society and the environment of geoenvironmental disasters triggered by various types of geo-hazards (e.g. earthquakes, volcanic activity, landslides, tsunamis, intensive erosion and hydro-meteorological events). The integrated study of Geoenvironmental Disasters is an emerging and composite field of research interfacing with areas traditionally within civil engineering, earth sciences, atmospheric sciences and the life sciences. It centers on the interactions within and between the Earth''s ground, air and water environments, all of which are affected by climate, geological, morphological and anthropological processes; and biological and ecological cycles. Disasters are dynamic forces which can change the Earth pervasively, rapidly, or abruptly, and which can generate lasting effects on the natural and built environments. The journal publishes research papers, case studies and quick reports of recent geoenvironmental disasters, review papers and technical reports of various geoenvironmental disaster-related case studies. The focus on case studies and quick reports of recent geoenvironmental disasters helps to advance the practical understanding of geoenvironmental disasters and to inform future research priorities; they are a major component of the journal. The journal aims for the rapid publication of research papers at a high scientific level. The journal welcomes proposals for special issues reflecting the trends in geoenvironmental disaster reduction and monothematic issues. Researchers and practitioners are encouraged to submit original, unpublished contributions.