Seasonal trends of reservoir-triggered seismicity in Song Tranh 2 reservoir, Vietnam

2021 ◽  
Author(s):  
Grzegorz Lizurek ◽  
Konstantinos Leptokaropoulos ◽  
Jan Wiszniowski ◽  
Izabela Nowaczyńska ◽  
Nguyen Van Giang ◽  
...  
Keyword(s):  
Water Level ◽  
Pore Pressure ◽  
Seismic Activity ◽  
Water Level Fluctuations ◽  
Response Type ◽  
Seasonal Trends ◽  
Triggered Seismicity ◽  
Stress Orientation ◽  
Water Level Changes ◽  
Pressure Changes

<p>Reservoir-triggered seismicity (RTS) is the longest known anthropogenic seismicity type. It has the potential to generate seismic events of M6 and bigger. Previous studies of this phenomenon have proved that major events are triggered on preexisting major discontinuities, forced to slip by stress changes induced by water level fluctuations and/or pore-pressure changes in the rock mass in the vicinity of reservoirs. Song Tranh 2 is an artificial water reservoir located in Central Vietnam. Its main goal is back up the water for hydropower plant. 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 the lack of clear correlation between water level and seismic activity has 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. In this work, we 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. A stress orientation difference between low and high water periods is also revealed. The findings indicate that water load and related pore pressure changes influence seismic activity and stress orientation in this area.</p><p>This work was 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.</p>

scholarly journals The influence of long- and short-term volcanic strain on aquifer pressure: a case study from Soufrière Hills Volcano, Montserrat (W.I.)

2020 ◽  
Vol 223 (2) ◽  
pp. 1288-1303
Author(s):  
K Strehlow ◽  
J Gottsmann ◽  
A Rust ◽  
S Hautmann ◽  
B Hemmings
Keyword(s):  
Water Level ◽  
Pore Pressure ◽  
Crustal Deformation ◽  
Water Levels ◽  
Short Term ◽  
Soufriere Hills Volcano ◽  
Soufrière Hills Volcano ◽  
Water Level Changes ◽  
Soufriere Hills

Summary Aquifers are poroelastic bodies that respond to strain by changes in pore pressure. Crustal deformation due to volcanic processes induces pore pressure variations that are mirrored in well water levels. Here, we investigate water level changes in the Belham valley on Montserrat over the course of 2 yr (2004–2006). Using finite element analysis, we simulate crustal deformation due to different volcanic strain sources and the dynamic poroelastic aquifer response. While some additional hydrological drivers cannot be excluded, we suggest that a poroelastic strain response of the aquifer system in the Belham valley is a possible explanation for the observed water level changes. According to our simulations, the shallow Belham aquifer responds to a steadily increasing sediment load due to repeated lahar sedimentation in the valley with rising aquifer pressures. A wholesale dome collapse in May 2006 on the other hand induced dilatational strain and thereby a short-term water level drop in a deeper-seated aquifer, which caused groundwater leakage from the Belham aquifer and thereby induced a delayed water level fall in the wells. The system thus responded to both gradual and rapid transient strain associated with the eruption of Soufrière Hills Volcano (Montserrat). This case study gives field evidence for theoretical predictions on volcanic drivers behind hydrological transients, demonstrating the potential of hydrological data for volcano monitoring. Interrogation of such data can provide valuable constraints on stress evolution in volcanic systems and therefore complement other monitoring systems. The presented models and inferred results are conceptually applicable to volcanic areas worldwide.

scholarly journals Inferring the role of habitat dynamics in driving diversification: evidence for a species pump in Lake Tanganyika cichlids

2016 ◽  
Author(s):  
Thijs Janzen ◽  
Rampal S. Etienne
Keyword(s):  
Water Level ◽  
Lake Tanganyika ◽  
Phylogenetic Reconstruction ◽  
Cichlid Fish ◽  
Species Tree ◽  
Water Level Fluctuations ◽  
Habitat Dynamics ◽  
Water Level Changes ◽  
Reconstruction Methods ◽  
Cyclic Changes

ABSTRACTGeographic isolation that drives speciation is often assumed to slowly increase over time, for instance through the formation of rivers, the formation of mountains or the movement of tectonic plates. Cyclic changes in connectivity between areas may occur with the advancement and retraction of glaciers, with water level fluctuations in seas between islands or in lakes that have an uneven bathymetry. These habitat dynamics may act as a driver of allopatric speciation and propel local diversity. Here we present a parsimonious model of the interaction between cyclical (but not necessarily periodic) changes in the environment and speciation, and provide an ABC-SMC method to infer the rates of allopatric and sympatric speciation from a phylogenetic tree. We apply our approach to the posterior sample of an updated phylogeny of the Lamprologini, a tribe of cichlid fish from Lake Tanganyika where such cyclic changes in water level have occurred. We find that water level changes play a crucial role in driving diversity in Lake Tanganyika. We note that if we apply our analysis to the Most Credible Consensus (MCC) tree, we do not find evidence for water level changes influencing diversity in the Lamprologini, suggesting that the MCC tree is a misleading representation of the true species tree. Furthermore, we note that the signature of habitat dynamics is found in the posterior sample despite the fact that this sample was constructed using a species tree prior that ignores habitat dynamics. However, in other cases this species tree prior might erase this signature. Hence we argue that in order to improve inference of the effect of habitat dynamics on biodiversity, phylogenetic reconstruction methods should include tree priors that explicitly take into account such dynamics.

scholarly journals Slow slip-driven seismic signature triggered by water-reservoir impoundment

2021 ◽  
Author(s):  
Beata Orlecka-Sikora ◽  
Lukasz Rudzinski ◽  
Grzegorz Lizurek ◽  
Dorota Olszewska ◽  
Taghi Shirzad
Keyword(s):  
Pore Pressure ◽  
Earthquake Swarm ◽  
Water Reservoir ◽  
Slow Slip ◽  
Hydroelectric Energy ◽  
Physical Mechanisms ◽  
Triggered Seismicity ◽  
Reservoir Impoundment ◽  
Geological Conditions ◽  
Pressure Changes

Abstract One of the most important and widely used renewable energy sources is hydroelectric energy produced via Water Reservoir Impoundment (WRI). WRI can trigger strong earthquakes under favourable geological conditions. Thus, the socio-economic impact of reservoir triggered seismicity is very significant. Although many studies have investigated the relationship between the pore pressure changes due to WRI and the observed seismicity, hydromechanical models that explain the observed processes are rare. Here, we investigate the role of hydromechanical interactions during fault deformation to understand earthquake swarm bursts under pore pressure changes due to WRI. As a natural laboratory, we selected the Song Tranh 2 Reservoir in Vietnam. Because the analysed triggered seismicity has swarm characteristics, our work contributes to the further investigation of the physical mechanisms responsible for earthquake swarms and their relationship to slow slip. We conclude that the small high-frequency seismic swarms accompanying WRI are driven by slow slip along a fault; they occur due to the temperature-controlled frictional fault heterogeneity, and their rate and magnitude depend on the sizes of these heterogeneities. Swarm earthquakes are the effect of slip acceleration on the seismic radiation level. The nucleation fronts expand the nucleation regime and may transition into stronger earthquakes. These results provide insights into the physical mechanisms of seismic processes triggered by WRI, which may have implications for assessing the seismic hazards associated with hydroelectric energy production.

scholarly journals VIBRATION FORECASTING BY THE RESULTS OF SYNCHRONOUS CONTROL OF WATER LEVEL CHANGES IN SEVERAL OBSERVING WELLS

2021 ◽  
Vol 2021 (2) ◽  
pp. 4383-4387
Author(s):  
ANTON PANDA ◽  
◽  
VOLODYMYR NAHORNYI ◽  
PETER PIGULEVSKY ◽  
IVETA PANDOVA ◽  
...  
Keyword(s):  
Water Level ◽  
Water Level Fluctuations ◽  
Distant Source ◽  
Synchronous Control ◽  
Water Level Changes ◽  
Measurement Results ◽  
Synchronous Measurement

The article presents the results of approbation the vibration forecasting methodology based on the synchronous measurement results of water level fluctuations in several observing wells. These fluctuations are caused by the shocks impact generated in a distant source of a maturing vibrations. The approbation demonstrated the reliable forecast possibility of earthquake time and its epicenter coordinates.

scholarly journals Tidal Behavior and Water-Level Changes in Gravel Aquifers in Response to Multiple Earthquakes: A Case Study From New Zealand

2021 ◽  
Author(s):  
KC Weaver ◽  
ML Doan ◽  
SC Cox ◽  
John Townend ◽  
C Holden
Keyword(s):  
New Zealand ◽  
Water Level ◽  
Dynamic Stress ◽  
Near Field ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Water Level Changes ◽  
Canterbury Earthquake Sequence ◽  
American Geophysical ◽  
American Geophysical Union

©2019. American Geophysical Union. All Rights Reserved. Earthquakes have been inferred to induce hydrological changes in aquifers on the basis of either changes to well water-levels or tidal behavior, but the relationship between these changes remains unclear. Here, changes in tidal behavior and water-levels are quantified using a hydrological network monitoring gravel aquifers in Canterbury, New Zealand, in response to nine earthquakes (of magnitudes M w 5.4 to 7.8) that occurred between 2008 and 2015. Of the 161 wells analyzed, only 35 contain water-level fluctuations associated with “Earth + Ocean” (7) or “Ocean” (28) tides. Permeability reduction manifest as changes in tidal behavior and increased water-levels in the near field of the Canterbury earthquake sequence of 2010–2011 support the hypothesis of shear-induced consolidation. However, tidal behavior and water-level changes rarely occurred simultaneously (~2%). Water-level changes that occurred with no change in tidal behavior reequilibrated at a new postseismic level more quickly (on timescales of ~50 min) than when a change in tidal behavior occurred (~240 min to 10 days). Water-level changes were more than likely to occur above a peak dynamic stress of ~50 kPa and were more than likely to not occur below ~10 kPa. The minimum peak dynamic stress required for a tidal behavior change to occur was ~0.2 to 100 kPa.

Analysis of pore water pressures in an earth dam under operating conditions (case of Taksebt Dam, Algeria)

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Farid Terbouche ◽  
Ali Hamza ◽  
Smail Gabi
Keyword(s):  
Water Level ◽  
Pore Pressure ◽  
Pore Water ◽  
Numerical Results ◽  
Operating Conditions ◽  
Earth Dam ◽  
Water Level Fluctuations ◽  
Average Error ◽  
Content Type ◽  
Pore Water Pressures

Purpose The purpose of this paper is the analysis of the dissipation of pore water pressures in the core of an earth dam, under the effect of water level fluctuations in the reservoir under operating conditions, taking into account the partial emptying and filling. Design/methodology/approach The Taksebt Dam, Tizi-Ouzou, Algeria was chosen as a case study, using a two-dimensional transient finite element numerical model. The GeoStudio calculation software is used through the SEEP/W. The latter takes into account the flow in the saturated and unsaturated zone, the formulation of SEEP/W allows the analysis of the dissipation of pore water pressures in the dyke. Starting from the maximum level of the reservoir, at least one cycle of partial emptying-filling was modelled over an eight-year operating period from 2011 to 2019. The input variables were the water level variation curve, material properties and boundary conditions. Findings It can be concluded that the numerical results obtained from the simulation model on the different points studied, namely, the pore water pressures are satisfactory as long as they are close to those recorded in the field by the pore pressure cells with an average error not exceeding 10% except for some measurements where the error is 20%. When the water level in the reservoir varies, the pore water pressures vary and their behaviour follows these fluctuations. Some points in the dam are affected by negative pore water pressures. No abnormal situations have been detected pore water pressures. Originality/value The numerical results of the simulation are analysed and validated against actual pore pressure cell measurements under operating conditions.

Vegetative and reproductive responses of charophytes to water-level fluctuations in permanent and temporary wetlands in Australia

1994 ◽  
Vol 45 (8) ◽  
pp. 1409 ◽  
Author(s):  
MT Casanova
Keyword(s):  
Sexual Reproduction ◽  
Water Level ◽  
Important Determinant ◽  
Dry Weight ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Water Level Changes ◽  
Sexual Responses ◽  
Chara Australis ◽  
Response To Water

Chara australis responded to changes in water levels by altering its morphology and allocation of resources. In a field harvest experiment, vegetative vigour of C. australis was greatest after water-level rises and the overall morphology of the plants varied depending upon season and site of collection. Allocation of dry weight varied over time, but allocation to sexual reproduction was always less than 10% of the total in this dioecious perennial species. C. australis reproduced sexually through the spring, summer and autumn, and where water levels were continually decreasing more female than male shoots were present. Field growth rates increased when depth was increased, and sexual reproduction was stimulated when water levels fell. An annual charophyte species (Nitella sonderi) did not display significant vegetative or sexual responses to water-level changes. The results of these experiments show that charophyte species can display morphological and reproductive plasticity in response to water level changes, although as charophytes are not uniform in their adaptations to fluctuations, results from one species cannot be extrapolated to another species. Life history could be a more important determinant of vegetative and reproductive characteristics than is phylogenetic affinity.

scholarly journals Identifying plausible historical scenarios for coupled lake level and seismicity rate changes: The case for the Dead Sea during the last two millennia

2021 ◽  
Author(s):  
Mariana Belferman ◽  
Amotz Agnon ◽  
Regina Katsman ◽  
Zvi Ben-Avraham
Keyword(s):  
Water Level ◽  
Dead Sea ◽  
Water Level Fluctuations ◽  
Earthquake Catalog ◽  
Seismicity Rate ◽  
Water Level Changes ◽  
The Dead ◽  
Seismic Stress ◽  
Synthetic Catalog ◽  
Seismicity Rate Changes

Abstract. Seismicity triggered by water level changes in reservoirs and lakes is usually studied from well-documented contemporary records. Can such triggering be explored on a historical time scale when the data gathered on water level fluctuations in historic lakes and the earthquake catalogs suffer from severe uncertainties? These uncertainties stem from the different nature of the data gathered, methods, and their resolution. In this article, we considerably improve the correlation between the continuous record of historic water level reconstructions at the Dead Sea and discrete seismicity patterns in the area over the period of the past two millennia. Constricted by the data from previous studies, we generate an ensemble of random water level curves and choose that curve that best correlates with the historical records of seismic stress release in the Dead Sea reflected in the destruction in Jerusalem. We then numerically simulate a synthetic earthquake catalog using this curve. The earthquakes of this synthetic catalog show an impressing agreement with historic earthquake records from the field. We demonstrate for the first time that water level changes correlate well with the observed recurrence interval record of historic earthquakes.

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