Microtremor-Based Seismic Vulnerability Characteristics in Mataram City
DOI:
https://doi.org/10.31305/rrijm.2024.v09.n05.026Keywords:
Microtremor, Seismic Vulnerability Characteristics, MataramAbstract
Mataram City is an area which is composed by thick deposits of volcanic material and has high seismic activity. When an earthquake occurs, seismic waves which is trapped in thick layers of sediment can cause severe damage to buildings. The mapping of seismic vulnerability in the Mataram City is needed to be carried out considering that Mataram City is the capital of West Nusa Tenggara province where there are many high buildings and high levels of human activity. The method that can be used to determine the vulnerability of the soil in an area is by using the HVSR (Horizontal to Vertical Spectral Ratio) method. Therefore, the dominant period values and seismic vulnerability index can be obtained in the research area. In addition, the shear strain values which was measured in the research area indicate the strength of the strain level in the constituent materials during the earthquake. The strength of the shear strain is obtained by multiplying the seismic vulnerability index (Kg) based on microtremors with the PGA value in the bedrock. Based on the results of the data processing, the dominant period (T0) value in the Mataram City is between 0.07-1.65 s, the seismic vulnerability value (Kg) ranges between 0.12 – 137.03 and the Ground Shear Strain (GSS) range is between 1.3 x 10-5 – 1.5 x 10 -3. Based on the research results, it can be concluded that Sekarbela District, Mataram District, and Labuapi District have high seismic vulnerability and also have damage impacts in the form of land shifting and subsidence.
References
Agustawijaya, D et al, 2020, An update to seismic hazard levels and PSHA for Lombok and surrounding islands after earthquakes in 2018, Bulletin of the New Zealand Society for Earthquake Engineering, Vol. 53(4):215-226
Bambang et al, 2022, Correlation between Building Damages and Losses with the Microzonation Map of Mataram—Case Study:Lombok Earthquake 2018, Indonesia Sustainability 2022, 14(4)
Daryono. (2012). Indeks Kerentanan Seismik Berdasarkan Mikrotremor pada setiap satuan bentuk Lahan di Zona Graben Bantul Daerah Istimewa Yogkarta. Yogyakarta: Disertasi, Universitas Gadjah Mada.
Hamilton, W., 1979. Tectonic of the Indonesian Region. U.S. Geological Survey. Profesional Paper 1078, 345 pp.
Ishihara, K. (1982). Evaluation of Soil Properties for use in earthquake response analysis. Proceedings International Symo. On Num. Model in Geomechanics, (hal. 237-259).
Irsyam et al. 2010, Development of spectral hazard maps for a proposed revision of the Indonesian Seismic Building Code, Geomechanics and Geoengineering, Volume 5, Issue 1 (2010)
McCaffrey, R. and Nabelek, J., 1987. Earthquakes, Gravity and the Origin of the Bali Basin: an Example of a Nascent Continental Fold-and-Thrust Belt, Journal of Geophysical Research, 92, No. B1, pp. 441-460.
Nakamura, Y., 1989, A method for Dynamic Characteristics Estimation of Subsurface using Microtremor on the Ground Surface, Quarterly Report of RTRI, Advance Access published 1989.
Nakamura, Y. and Takizawa, T. (1990), ”Evaluation of Liquefaction of Surface Ground using Microtremor (in Japanese)”, Proc. 45th Annual Meeting of JSCE, I-519,1068-1069.
Nakamura, Y. (1996),” Real Time Information Systems for Seismic Hazards Mitigation UrEDAS, HERAS and PIC”, Quarterly Report of RTRI, Vol. 37, No. 3, 112-127.
Nakamura, Y., 1997, Seismic vulnerability indices for ground and structures using microtremor, World Congress on Railway Research, Vol. 1, pp 1–7.
Nakamura, Y., 2000, Clear identification of fundamental idea of Nakamura’s technique and its applications, Proceedings of the 12th world conference on…, pp Paper no. 2656.
Pusat Studi Gempa Nasional (2018). Kajian Rangkaian Gempa Lombok Provinsi Nusa Tenggara Barat 29 Juli 2018 (M6.4), 5 Agustus 2018 (M7.0) 2017, 19 Agustus 2018 (M6.9),Jakarta
Zhao 2006, An Empirical Site-Classification Method for Strong-Motion Stations in Japan Using H/V Response Spectral Ratio, Bulletin of the Seismological Society of America, Vol. 96, No. 3, pp. 914–925, June 2006, doi: 10.1785/0120050124
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