Source Structure Characterization and Seismic Hazard Assessment of Reservoir-Triggered Earthquakes: A Case Study of Song Tranh 2 Hydropower Reservoir, Vietnam
Article Sidebar
Main Article Content
Abstract
The Song Tranh 2 hydropower reservoir (ST2), located in Bac Tra My district, Quang Nam province (Vietnam) was impounded in November 2010 and soon after that earthquakes began to occur with the largest earthquake of M = 4.9 occurred on 15 November 2012. Seismic activity has not shown any signs of stopping, by the end of 2021 there have been 1161 events of M≥1.5 recorded. The identification of the generating source zones, the maximum of triggered earthquake and its impact on the safety of the ST2 dam is a necessary task. This paper presents a three-step process to determine the generating triggered seismic source: identifying the existence of subsurface faults, determining the generating triggered seismic source and studying the structure of the generating source segments. This information is used to assess seismic hazard by applying the OpenQuake program. The studied results have identified five source segments including: segment F1.1 (maximum observed earthquake - MOb.max = 4.2) belongs to Tra Bong River fault; F2.1 (MOb.max = 4.7) belongs to Tra My fault; F3.1 (MOb.max = 4.1) and F3.2 (MOb.max = 4.1) belong to Nuoc Le River fault; and F4.1 (MOb.max = 3.6) belongs to Tra No River fault. The assessment of pick ground acceleration (PGA) of triggered earthquake that has potentially impact on the ST2 dam conducted with two scenarios: 1) MOb.max at respective source segments and 2) Maximum credible triggered earthquake (MMax = 4.9) at all source segments. In the second scenario (MMax=4.9) will result in a value of PGA = 0.180g, PGV = 6.0cm/s and PGD = 1.30cm (at 10% probability of exceedance in 50 years) at the ST2 dam will not adversely affect dam safety as it is designed to resist earthquakes at acceleration of 0.245g (M5.5).
Article Details
Copyright (c) 2026 Dinh TC, et al.
This work is licensed under a Creative Commons Attribution 4.0 International License.
Dinh TC, Bach MX, Hung PN, et al. Seismic hazard assessment for South-Central Region, Vietnam. In: Proc Int Conf Innovations for Sustainable and Responsible Mining. LNCE 108. Springer; 2021. p.167-191. Available from: https://doi.org/10.1007/978-3-030-60269-7_9
Telesca L, Thai AT, Cao DT, Ha TG. Spectral evidence for reservoir-triggered seismicity at Song Tranh 2 Reservoir (Vietnam). Pure Appl Geophys. 2021;178:3817-3828. Available from:
https://doi.org/10.1007/s00024-021-02858-0
Thai AT, Rao NP, Gahalaut K, et al. Evidence that earthquakes have been triggered by reservoir in the Song Tranh 2 region, Vietnam. J Seismol. 2017;21(5):1131-1143. Available from:
https://doi.org/10.1007/s10950-017-9656-2
Dinh TC, Dinh TC, Thai AT, et al. Overview of the characteristics of reservoir-triggered seismic activity at some hydropower reservoirs in Vietnam. J Geol Soc India. 2021;97(12):1574-1582. Available from:
https://doi.org/10.1007/s12594-021-1915-8
Nguyen HP, Pham TT, Nguyen TN. Probabilistic seismic hazard assessment for the Tranh River hydropower plant No2 site, Quang Nam province. Vietnam J Earth Sci. 2016;38(2):188-201. Available from:
https://doi.org/10.15625/0866-7187/38/2/8601
Gupta HK. Encyclopedia of Solid Earth Geophysics. Amsterdam: Springer; 2011. Available from: https://doi.org/10.1007/978-90-481-8702-7
Bui VD, Ha TG, Nguyen AD, Pham DN. About factors related to the occurrence of earthquakes in the Song Tranh 2 hydropower area in period 2011-2014. Vietnam J Earth Sci. 2015;37(3):228-240. Available from: https://doi.org/10.15625/0866-7187/37/3/7373
Carder DS. Seismic investigations in the Boulder Dam area, 1940–44, and the influence of reservoir loading on local earthquake activity. Bull Seismol Soc Am. 1945;35(4):175-192.
Hamada GM. Reservoir fluids identification using Vp/Vs ratio?. Oil Gas Sci Technol. 2004;59(6):649-654. Available from:
https://doi.org/10.2516/ogst:2004046
Lizurek G, Wiszniowski J, Nguyen VG, et al. Clustering and stress inversion in the Song Tranh 2 Reservoir, Vietnam. Bull Seismol Soc Am. 2017;107(6):2636-2648. Available from: https://doi.org/10.1785/0120170042
Cat Nguyen Hung, et al. Report on geological surveying and mineral prospecting of Tam Ky-Hiep Duc group, at scale 1:50,000. Geological archives. Hanoi; 1991. (in Vietnamese).
Barbosa VCF, Silva JBC. Generalized compact gravity inversion. Geophysics. 1994;59(1):57-68. Available from:
https://doi.org/10.1190/1.1443573
Blakely RJ. Potential Theory in Gravity and Magnetic Applications. Cambridge: Cambridge University Press; 1995. Available from:
https://doi.org/10.1017/CBO9780511549816
Blakely RJ, Simpson RW. Approximating edges of source bodies from magnetic or gravity anomalies. Geophysics. 1986;51(7):1494-1498. Available from: https://doi.org/10.1190/1.1442197
Wang J, Meng XH, Li F. Improved curvature gravity gradient tensor with principal component analysis and its application in edge detection of gravity data. J Appl Geophys. 2015;118:106-114. Available from:
https://doi.org/10.1016/j.jappgeo.
Chen AG, Zhou TF, Liu DJ, Zhang S. Application of an enhanced Theta-Based Filter for potential field edge detection: A case study of the Luzong ore district. Chin J Geophys. 2017;60(2):203-218. Available from: https://dx.doi.org/10.6038/cjg20170228
Cooper GRJ, Cowan DR. Edge enhancement of potential-field data using normalized statistics. Geophysics. 2008;73(3):H1-H4.
Silva JBC, Barbosa VCF. Interactive gravity inversion. Geophysics. 2006;71(1):J1-J9. Available from: https://dx.doi.org/10.1190/1.2168010
Cao Dinh Trong, Pham Nam Hung, Dinh Quoc Van, Le Quang Khoi. Seismic tomographic model of Song Tranh 2 hydropower plant. Geology J Ser A. 2014;(341-345). (in Vietnamese).
Koulakov I. LOTOS code for local earthquake tomographic inversion: Benchmarks for testing tomographic algorithms. Bull Seismol Soc Am. 2009;99(1):194-214. Available from: https://doi.org/10.1785/0120080013
Keller EA, Pinter N. Active Tectonics: Earthquakes, Uplift and Landscape. New Jersey: Prentice Hall; 2002. 362 p.
Kijko A. Estimation of the maximum earthquake magnitude, mmax. Pure Appl Geophys. 2004;161(8):1655-1681.
Pagani M, Monelli D, Weatherill G, et al. OpenQuake Engine: An open hazard (and risk) software for the Global Earthquake Model. Seismol Res Lett. 2014;85(3):692-702. Available from:
https://doi.org/10.1785/0220130087
Campbell KW, Bozorgnia Y. NGA-West2 ground motion model for the average horizontal components of PGA, PGV, and 5% damped linear acceleration response spectra. Earthq Spectra. 2014;30(3):1087-1115.
Global Earthquake Model (GEM). The OpenQuake-engine User Manual. Engine version 3.8.1. 2020. 183 p. doi: 10.13117/GEM.OPENQUAKE.MAN.ENGINE.3.8.1
Cao Đinh Trieu, Nguyen Đuc Vinh. Fault segmentation in assessing maximum credible earthquake in Vietnam. Geology J. 2012;(331-332):59-68. (in Vietnamese).
Trieu CD, Trong CD, Tuan TA, Van DQ, Dung LV, Long HV. Triggered earthquake study in Tranh River no. 2 (Vietnam), hydropower reservoir. J Geol Soc India. 2014;84:319-325. Available from:
https://doi.org/10.1007/s12594-014-0135-x
Cao Đinh Trieu. Assess the situation of seismic activity in the Song Tranh 2 region and propose solutions to prevent and mitigate damage. Summary report of project VUSTA. Hanoi; 2012. 230 p. (in Vietnamese).