SITE EFFECTS IDENTIFICATION USING HVSR METHOD IN CISARUA HOT SPRING AREA, NATAR, SOUTH LAMPUNG
DOI:
https://doi.org/10.23960/jge.v11i2.494Keywords:
Cisarua, Geothermal, HVSR, Site effectsAbstract
Cisarua, which contains a geothermal hot spring, is an intriguing area to investigate due to its location far from any known heat source or volcanic activity. Using the HVSR technique, this study aims to characterize the local site effects based on key parameters: natural frequency (fo), amplification factor (Ao), and average shear-wave velocity down to 30 meters depth (Vs30). Microtremor measurements were conducted at 25 locations across the Cisarua hot spring area, with an average spacing of 300 meters. Each site was recorded for 40–50 minutes, and the data were processed using Geopsy software to extract the HVSR curves, along with the fo and Ao values. The HVSR curves were then inverted using the Particle Swarm Optimization (PSO) algorithm to derive Vs30 values. The results show that fo values range from 0.6 to 1.1 Hz, and Vs30 values are generally below 175 m/s. These two parameters exhibit minimal spatial variation, indicating the presence of thick, soft, and relatively homogeneous sedimentary layers across most of the study area. The Ao values range from 2 to 5, with values below 3 dominating near the geothermal manifestation zone. The spatial distribution of fo and Ao reveals a northwest–southeast trend, which is strongly correlated with the presence of the Lampung–Panjang Fault that likely controls sediment accumulation and layer thickness in the area. Around point T13, Vs30 drops to 125–150 m/s, suggesting localized softening of the soil due to hydrothermal alteration processes. These findings emphasize the interplay between site effects, regional geological structures, and geothermal activity in shaping the dynamic properties of the subsurface in this area.
References
Ariyanto, A., Farduwin, A., Styawan, Y., Putri, I.A., Junian, W.E., Prasetyo, N., Rizki, R., & Wulandari, R. (2024). Seismic Vulnerability Microzonation Through HVSR Microtremor Analysis in The Kemiling District and Its Surroundings. JGE (Jurnal Geofisika Eksplorasi), 10(2), 82–99. https://doi.org/10.23960/jge.v10i2.393
Ashayeri, I., Shahvar, M. P., & Moghofeie, A. (2022). Seismic Characterization of Iranian Strong Motion Stations in Kermanshah Province (Iran) Using Single-Station Rayleigh Wave Ellipticity Inversion of Ambient Noise Measurements. Bulletin of Earthquake Engineering, 20(8), 3739–3773. https://doi.org/10.1007/s10518-022-01370-7
Barber, A. J. & Crow, M. J. (2005). Chapter 4: Pre-Tertiary Stratigraphy. Memoirs, 31(1), 24–53. https://doi.org/10.1144/GSL.MEM.2005.031.01.04
European Commitee for Standardization (2004). Eurocode 8: Design of Structures For Earthquake Resistance - Part 1 : General Rules, Seismic Actions and Rules For Buildings. In European Committee for Standardization (Vol. 1, Issue English). The European Union Per Regulation 305/2011, Directive 98/34/EC, Directive 2004/18/EC.
Farduwin, A., Antosia, R. M., Putri, I. A., Santoso, N. A., & Irawati, S. M. (2021). Geoelectrical Data Inversion Using Particle Swarm Optimization: Case Study of Gayau Village. JGE (Jurnal Geofisika Eksplorasi), 7(2), 88–99. https://doi.org/10.23960/jge.v7i2.118
Farduwin, A. & Yudistira, T. (2021). Shear Velocity Inversion From Ambient Seismic Noise Using RR-PSO: A Case Study of Nusa Tenggara Island. Journal of Physics: Conference Series, 1949(1), 012022. https://doi.org/10.1088/1742-6596/1949 /1/012022
Field, E. H. & Jacob, K. H. (1995). A Comparison And Test of Various Site-Response Estimation Techniques, Including Three That Are Not Reference-Site Dependent. Bulletin of the Seismological Society of America, 85(4), 1127–1143.
Herak, M. (2008). ModelHVSR—A Matlab® Tool To Model Horizontal-To-Vertical Spectral Ratio of Ambient Noise. Computers & Geosciences, 34(11). https://doi.org/10.1016 /j.cageo.2007.07.009
Juliarka, B. R. & Iqbal, M. (2020). 2D Conceptual Model on Natar Geothermal System Based on Gravity Data. Buletin SDG, 15(1), 39–49. https://doi.org/10.47599/bsdg.v15i1.292
Kawase, H., Mori, Y., & Nagashima, F. (2018). Difference of Horizontal-To-Vertical Spectral Ratios of Observed Earthquakes and Microtremors and Its Application to S-Wave Velocity Inversion Based on The Diffuse Field Concept. Earth, Planets and Space, 70(1). https://doi.org/10.1186/s40623-017-0766-4
Karyanto, Sihabudin, A., Darmawan, I.G.B. Suharno, & Manurung, P. (2024). Characterizing Near-Surface Features of Shallow Shear Wave Velocity in The Way Ratai Geothermal Field. Environmental Earth Sciences 83, 90 https://doi.org/10.1007/ s12665-023-11235-0
Konno, K. & Ohmachi, T. (1998). Ground-Motion Characteristics Estimated From Spectral Ratio Between Horizontal and Vertical Components of Microtremor. Bulletin of the Seismological Society of America, 88(1), 228–241. https://doi.org/10.1785/bssa08800 10228
Laby, D.A., Sungkono, Santosa, B.J., & Bahri, A.S. (2016). RR-PSO: Fast and Robust Algorithm To Invert Rayleigh Waves Dispersion. Computational Ecology and Software, 9, 735–741. https://doi.org/10.12988/ces.2016.66 85
Lachet, C. & Bard, P.Y. (1994). Numerical and Theoretical Investigations on The Possibilities and Limitations of the Nakamura’s Technique. Journal of Physics of the Earth, 42(5), 377–397. https://doi.org/10.4294/jpe1952.42.377
Maghami, S., Sohrabi-Bidar, A., Bignardi, S., Zarean, A., & Kamalian, M. (2021). Extracting The Shear Wave Velocity Structure of Deep Alluviums of ‘Qom’ Basin (Iran) Employing HVSR Inversion of Microtremor Recordings. Journal of Applied Geophysics, 185, 104246. https://doi.org/10.1016/j.jappgeo.2020.104246
Mangga, S. A., Amirudin, Suwarti, T., Gafoer, S., & Sidarto (1993). Geological Map of Tanjungkarang, Sumatra. Bandung: Geological Research and Development Centre.
Nakamura, Y. (1989). Method for Dynamic Characteristics Estimation of Subsurface Using Microtremor on The Ground Surface. Quarterly Report of RTRI (Railway Technical Research Institute) (Japan), 30(1), 25–33.
Nelson, S. & McBride, J. (2019). Application of HVSR to Estimating Thickness of Laterite Weathering Profiles in Basalt. Earth Surface Processes and Landforms, 44(7), 1365–1376. https://doi.org/10.1002/esp.4580
Pinem, J.C.D.B., Farduwin, A., & Styawan, Y. (2024). Pemanfaatan Metode HVSR Untuk Studi Karakteristik Tanah di Tanjung Kemala Daerah Kabupaten Tanggamus. Jurnal Geosaintek, 10(2), 106–122. https://doi.org/10.12962/j25023659.v10i2.1619
Putri, I.A., Antosia, R.M., Farduwin, A., Rizki, R., Styawan, Y., & Hasiany, S. (2023). Identification of Aquifer, Ground Water-Bearing Rock, Using Vertical Electrical Sounding (VES): East Lampung Case Study. Jurnal Geosains Indonesia, 7(1).
Rubaiyn, A., Hamimu, L., & Mukarramah, M. (2023). Microzonation of Soil Fragility Index in Nambo, Kendari Using Horizontal-To-Vertical Spectral Ratio. JGE (Jurnal Geofisika Eksplorasi), 9(3), 194–205. https://doi.org/10.23960/jge.v9i3.292
SESAME Project (2004). Guidelines For The Implementation of The H/V Spectral Ratio Technique on Ambient Vibrations—Measurements, Processing and Interpretations. European Research Project SESAME.
Suharno, R.B., Aritonang, B., Zaenudin, A., & Rustadi (2012). Sistem Panas Bumi Cisarua Natar Lampung Selatan. In Proceeding of the 12th Annual Indonesian Geothermal Association Meeting & Conference.
Trichandi, R., Bauer, K., Ryberg, T., Wawerzinek, B., & Araya, J. (2023). Shear-Wave Velocity Imaging of Weathered Granite in La Campana (Chile) From Bayesian Inversion Of Micro-Tremor H/V Spectral Ratios. Journal of Applied Geophysics. https://doi.org/10. 1016/j.jappgeo.2023.105152
Zaenudin, A., Darmawan, I. G. B., Farduwin, A., & Wibowo, R. C. (2022). Shear Wave Velocity Estimation Based on The Particle Swarm Optimization Method of HVSR Curve Inversion In Bakauheni District, Indonesia. Turkish Journal of Earth Sciences. https://doi.org/10.55730/1300-0985.1815
Zaenudin, A., Farduwin, A., Darmawan, G. I. B., & Karyanto (2024). Shear Wave Velocity Model Using HVSR Inversion Beneath Bandar Lampung City. Earthquake Science, 37(4), 337–351. https://doi.org/10.1016/j.eqs. 2024.04.004
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