Ahmad Zaenudin , Alhada Farduwin , Gede I. Boy Darmawan , Karyanto
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Bandar Lampung is a city in Lampung Province with many fault structures and groundwater basins to the south. There are 83 HVSR measurement points around Bandar Lampung for delineating the presence of fault structures and groundwater basins. We produced the HVSR curve from the measurement results and then performed an inversion process using the particle swarm optimization algorithm to obtain <em>v</em><sub>S</sub> for the depth profile. Subsequently, from this profile, we produced a two-dimensional (2D) lateral and vertical model. The mean <em>v</em><sub>S</sub> value was calculated from all the measurement points, and we found stiff soil layers reaching depths of approximately 5 m, with a value of <em>v</em><sub>S</sub> < 330 m/s. A bedrock layer with a velocity exceeding 1250 m/s was visible at a depth of 100 m. Based on the 2D model, the <em>v</em><sub>S</sub> structure shows that the city of Bandar Lampung is divided into two zones, with a NW-SE boundary. The north-middle-eastern part of the city consists of harder rocks. This harder rock is characterized by extremely high <em>v</em><sub>S</sub> values, starting from a depth of 50 m. In contrast, the south-middle-west exhibits a low-moderate <em>v</em><sub>S</sub> anomaly associated with groundwater basins SW of the city. From the 2D <em>v</em><sub>S</sub> structural model, fault structures can be found along the city, characterized by a contrast of <em>v</em><sub>S</sub> values from low to medium and from medium to high.</p></div>","PeriodicalId":46333,"journal":{"name":"Earthquake Science","volume":"37 4","pages":"Pages 337-351"},"PeriodicalIF":1.2000,"publicationDate":"2024-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674451924000478/pdfft?md5=69840edfcf9764edc9f33466eb7d73e0&pid=1-s2.0-S1674451924000478-main.pdf","citationCount":"0","resultStr":"{\"title\":\"Shear wave velocity model using HVSR inversion beneath Bandar Lampung City\",\"authors\":\"Ahmad Zaenudin , Alhada Farduwin , Gede I. 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引用次数: 0
摘要
水平-垂直谱比(HVSR)方法已被用于表征场地效应参数,这些参数在城市地区的地震危害和风险降低研究以及快速土地利用规划中不可或缺。这种方法被广泛使用,因为它是采集和处理阶段最便宜、最简单的地球物理方法。在随后的发展中,HVSR 方法被广泛用于通过 HVSR 曲线反演过程确定弹性岩石参数,特别是剪切波速度(vS)。此外,vS 结构模型还可用于划分复杂地质结构的存在,尤其是断层和沉积盆地。Bandar Lampung 是楠榜省的一个城市,其南部有许多断层结构和地下水盆地。万达楠榜周围有 83 个 HVSR 测量点,用于划分断层结构和地下水盆地。我们根据测量结果绘制了 HVSR 曲线,然后使用粒子群优化算法进行反演,以获得深度剖面的 vS。随后,我们根据该剖面制作了二维(2D)横向和纵向模型。通过计算所有测量点的平均 vS 值,我们发现僵硬土层的深度约为 5 米,其 vS 值为 330 米/秒。根据二维模型,vS 结构显示楠榜万达市分为两个区域,以西北-东南为界。城市的中北部由较坚硬的岩石组成。相比之下,中西部偏南地区的 vS 值较低,与该市西南部的地下水盆地有关。从二维 vS 结构模型中可以发现,城市沿线存在断层结构,其特征是 vS 值从低到中和从中到高的对比。
Shear wave velocity model using HVSR inversion beneath Bandar Lampung City
The horizontal-to-vertical spectral ratio (HVSR) method has been used to characterize site-effect parameters that are indispensable in seismic hazard and risk-reduction studies in urban areas and rapid land-use planning. This method is widely used because it is the cheapest and simplest geophysical method for the acquisition and processing stages. In subsequent developments, the HVSR method has been widely used to determine elastic rock parameters, particularly shear wave velocity (vS), through the HVSR curve inversion process. Furthermore, the vS structural model can be used to delineate the presence of complex geological structures, particularly faults and sedimentary basins. Bandar Lampung is a city in Lampung Province with many fault structures and groundwater basins to the south. There are 83 HVSR measurement points around Bandar Lampung for delineating the presence of fault structures and groundwater basins. We produced the HVSR curve from the measurement results and then performed an inversion process using the particle swarm optimization algorithm to obtain vS for the depth profile. Subsequently, from this profile, we produced a two-dimensional (2D) lateral and vertical model. The mean vS value was calculated from all the measurement points, and we found stiff soil layers reaching depths of approximately 5 m, with a value of vS < 330 m/s. A bedrock layer with a velocity exceeding 1250 m/s was visible at a depth of 100 m. Based on the 2D model, the vS structure shows that the city of Bandar Lampung is divided into two zones, with a NW-SE boundary. The north-middle-eastern part of the city consists of harder rocks. This harder rock is characterized by extremely high vS values, starting from a depth of 50 m. In contrast, the south-middle-west exhibits a low-moderate vS anomaly associated with groundwater basins SW of the city. From the 2D vS structural model, fault structures can be found along the city, characterized by a contrast of vS values from low to medium and from medium to high.
期刊介绍:
Earthquake Science (EQS) aims to publish high-quality, original, peer-reviewed articles on earthquake-related research subjects. It is an English international journal sponsored by the Seismological Society of China and the Institute of Geophysics, China Earthquake Administration.
The topics include, but not limited to, the following
● Seismic sources of all kinds.
● Earth structure at all scales.
● Seismotectonics.
● New methods and theoretical seismology.
● Strong ground motion.
● Seismic phenomena of all kinds.
● Seismic hazards, earthquake forecasting and prediction.
● Seismic instrumentation.
● Significant recent or past seismic events.
● Documentation of recent seismic events or important observations.
● Descriptions of field deployments, new methods, and available software tools.
The types of manuscripts include the following. There is no length requirement, except for the Short Notes.
【Articles】 Original contributions that have not been published elsewhere.
【Short Notes】 Short papers of recent events or topics that warrant rapid peer reviews and publications. Limited to 4 publication pages.
【Rapid Communications】 Significant contributions that warrant rapid peer reviews and publications.
【Review Articles】Review articles are by invitation only. Please contact the editorial office and editors for possible proposals.
【Toolboxes】 Descriptions of novel numerical methods and associated computer codes.
【Data Products】 Documentation of datasets of various kinds that are interested to the community and available for open access (field data, processed data, synthetic data, or models).
【Opinions】Views on important topics and future directions in earthquake science.
【Comments and Replies】Commentaries on a recently published EQS paper is welcome. The authors of the paper commented will be invited to reply. Both the Comment and the Reply are subject to peer review.