Triggered Earthquake Study in Tranh River No. 2 (Vietnam) Hydropower Reservoir

Abstract

This article presents the results of investigating triggered earthquakes in the vicinity of Tranh River No.2 Hydropower Reservoir in recent years. It is found that earthquakes occurred in the vicinity of Tranh River Hydropower Reservoir, probably associated with the Trà My -Trà BÓng fault zone. It is estimated that this fault is capable of hosting an earthquake of M~6.1. The 'b' value for this earthquake sequence is 0.83, which is higher than the regional 'b' value of 0.60. We estimate that the return period of earthquakes of M=4.5, 5.0, 5.5 and 6.0 is 11, 29, 76 and 198 months respectively. On October 22, 2012 an earthquake M S =4.6, I 0 =6.0 (MSK-64) occurred at 13:41:28 hrs GMT. The epicenter of the earthquake was located at a distance of 5.5 km away from the center of the dam towards the west. The focal depth is about 4.5 km, and the rupture length is about 1.8 km.

Tectonic Stress Distribution in the Song Tranh 2 Hydropower Reservoir: Implication for Induced Earthquake

“…Studying the focal mechanism of 3 triggered earthquakes occurring in September and October 2013 by Giang et al 2015 [7] showed the heterogeneity of the focal mechanism and the faulting directions. Unlike the results obtained by Trieu et al 2014, studying the hypocenter distribution by Lizurek et al 2017 [8] suggested that almost triggered earthquakes were related to the NW-SE striking faults with normal focal mechanisms and only a few earthquakes related to E-W striking Bac Tra My-Tra Bong fault. However, studies on the focal mechanism and Coulomb stress change model by Gahalaut et al 2016 [9], Tuan et al 2017 [10] revealed a close relationship between triggered earthquake distribution, focal mechanisms and Coulomb stress change related to the NW-SE and sub-latitude faults determined by Hoai et al 2014 [3].…”

Assessment on maximum magnitude of natural and triggered earthquake when water is impounded in the mining pit: A case study in Nui Nho quarry, Vietnam based on gravity and magnetic data

“…The assessment of the maximum magnitude of natural earthquake plays an important role in calculating earthquake hazard and determining the maximum magnitude of the triggered earthquake if it occurs. The maximum magnitude of the triggered earthquake does not exceed that of natural earthquakes in the study area [Son, 2012;Trieu et al, 2014;Trong et al, 2016;Tuan et al, 2017]. In this paper, a comprehensive study is described which estimates source parameters, maximum magnitude of natural and triggered earthquakes.…”