Seasonal trends and relation to water level of reservoir-triggered seismicity in Song Tranh 2 reservoir, Vietnam
Seasonal trends and relation to water level of reservoir-triggered seismicity in Song Tranh 2 reservoir, Vietnam
Reservoir-triggered seismicity (RTS) has the potential to generate disastrous seismic events of M6 and bigger. Song Tranh 2 (STR2) is an artificial water reservoir located in Central Vietnam. High seismic activity has been observed in this area since the reservoir was first filled in 2011. The relation between water level and seismic activity in the Song Tranh area is complex, and previous studies have led to the conclusion that ongoing STR2 seismic activity is an example of the delayed response type of RTS. However, the first phase of the activity observed after impoundment has been deemed a rapid response type. There were three stages of the reservoir filling periods: first, a period of initial impoundment, hereinafter referred to as pre-gap period (from 05/01/2011 to 10/06/2012), then a gap period (from 10/06/2012 to 31/08/2013) where reservoir impoundment stopped and water was drained to minimum exploitation level, and finally, a third post-gap period (from 31/08/2013 to 19/06/2017). In this work, we prove that the gap in the filling of reservoir results to a 2-fold rise of seismicity rate. The re-filling of the reservoir results to a drop of activity rate, roughly equal to the pre-gap period, accompanied by a significant increase of b-value. As a consequence, after the gap, the exceedance probability is significantly lower in comparison to pre-gap and gap periods. We also proved that the seismicity recorded between 2013 and 2016 manifested seasonal trends related to water level changes during wet and dry seasons. The response of activity and its delay with respect to water level changes suggest that the main triggering factor is pore pressure change due to the significant water level changes observed. The findings indicate that water load and related pore pressure changes considerably influence seismic activity and stress orientation in this area.
Anthropogenic seismicity, Focal mechanism, Probabilistic seismic hazard, Reservoir-triggered seismicity, Stress inversion
Lizurek, Grzegorz
98af84df-4d57-4e0a-bde1-2894d1fe250e
Leptokaropoulos, Konstantinos
6176f4d8-7af0-4575-bf2c-5aaba3d182ce
Wiszniowski, Jan
565fdec7-8ab6-4c30-bf5d-432744362cc2
Van. Giang, Nguyen
5ac84da1-43fd-4254-8f49-7389b231c5b2
Nowaczyńska, Izabela
f1e4391e-0fa8-4329-a8b7-1933add79bb8
Plesiewicz, Beata
f496dcea-6507-41a8-9edf-0b86035f7740
Van, Dinh Quoc
91c1a9ac-3cef-42cf-9a1c-8a77cbb6376a
Tymińska, Anna
75662789-24b1-4b5e-b4c8-5da6d6e19018
5 December 2021
Lizurek, Grzegorz
98af84df-4d57-4e0a-bde1-2894d1fe250e
Leptokaropoulos, Konstantinos
6176f4d8-7af0-4575-bf2c-5aaba3d182ce
Wiszniowski, Jan
565fdec7-8ab6-4c30-bf5d-432744362cc2
Van. Giang, Nguyen
5ac84da1-43fd-4254-8f49-7389b231c5b2
Nowaczyńska, Izabela
f1e4391e-0fa8-4329-a8b7-1933add79bb8
Plesiewicz, Beata
f496dcea-6507-41a8-9edf-0b86035f7740
Van, Dinh Quoc
91c1a9ac-3cef-42cf-9a1c-8a77cbb6376a
Tymińska, Anna
75662789-24b1-4b5e-b4c8-5da6d6e19018
Lizurek, Grzegorz, Leptokaropoulos, Konstantinos and Wiszniowski, Jan
,
et al.
(2021)
Seasonal trends and relation to water level of reservoir-triggered seismicity in Song Tranh 2 reservoir, Vietnam.
Tectonophysics, 820 (12), [229121].
(doi:10.1016/j.tecto.2021.229121).
Abstract
Reservoir-triggered seismicity (RTS) has the potential to generate disastrous seismic events of M6 and bigger. Song Tranh 2 (STR2) is an artificial water reservoir located in Central Vietnam. High seismic activity has been observed in this area since the reservoir was first filled in 2011. The relation between water level and seismic activity in the Song Tranh area is complex, and previous studies have led to the conclusion that ongoing STR2 seismic activity is an example of the delayed response type of RTS. However, the first phase of the activity observed after impoundment has been deemed a rapid response type. There were three stages of the reservoir filling periods: first, a period of initial impoundment, hereinafter referred to as pre-gap period (from 05/01/2011 to 10/06/2012), then a gap period (from 10/06/2012 to 31/08/2013) where reservoir impoundment stopped and water was drained to minimum exploitation level, and finally, a third post-gap period (from 31/08/2013 to 19/06/2017). In this work, we prove that the gap in the filling of reservoir results to a 2-fold rise of seismicity rate. The re-filling of the reservoir results to a drop of activity rate, roughly equal to the pre-gap period, accompanied by a significant increase of b-value. As a consequence, after the gap, the exceedance probability is significantly lower in comparison to pre-gap and gap periods. We also proved that the seismicity recorded between 2013 and 2016 manifested seasonal trends related to water level changes during wet and dry seasons. The response of activity and its delay with respect to water level changes suggest that the main triggering factor is pore pressure change due to the significant water level changes observed. The findings indicate that water load and related pore pressure changes considerably influence seismic activity and stress orientation in this area.
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Accepted/In Press date: 17 October 2021
e-pub ahead of print date: 25 October 2021
Published date: 5 December 2021
Additional Information:
Funding Information:
Izabela Nowaczyńska research work was partially financed by the Ministry of Science and Higher Education (Poland) as part of internal IG PAS research project No. 500-10-50.
Funding Information:
Grzegorz Lizurek, Nguyen Van Giang, Izabela Nowaczyńska, Beata Plesiewicz, Konstantinos Leptokaropoulos and Jan Wiszniowski were partially supported by research project no. 2017/27/B/ST10/01267 , funded by the National Science Centre , Poland, under agreement no. UMO-2017/27/B/ST10/01267.
Funding Information:
Grzegorz Lizurek, Beata Plesiewicz and Jan Wiszniowski were also partially supported by statutory activity no. 3841/E-41/S/2021 of the Ministry of Science and Higher Education of Poland .
Publisher Copyright:
© 2021 The Authors
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
Keywords:
Anthropogenic seismicity, Focal mechanism, Probabilistic seismic hazard, Reservoir-triggered seismicity, Stress inversion
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Local EPrints ID: 453543
URI: http://eprints.soton.ac.uk/id/eprint/453543
ISSN: 0040-1951
PURE UUID: e9708f3f-d23b-483f-af60-94661a60abbd
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Date deposited: 19 Jan 2022 17:42
Last modified: 18 Mar 2024 04:00
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Author:
Grzegorz Lizurek
Author:
Jan Wiszniowski
Author:
Nguyen Van. Giang
Author:
Izabela Nowaczyńska
Author:
Beata Plesiewicz
Author:
Dinh Quoc Van
Author:
Anna Tymińska
Corporate Author: et al.
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