Quantitative Assessment of the Mechanisms of Earthquake-Induced Groundwater-Level Change in the MP Well, Three Gorges Area

2018 ◽  
pp. 69-78
Author(s):  
Shouchuan Zhang ◽  
Zheming Shi ◽  
Guangcai Wang ◽  
Zuochen Zhang
Keyword(s):  
Groundwater Level ◽  
Quantitative Assessment ◽  
Three Gorges ◽  
Three Gorges Area ◽  
Level Change ◽  
Groundwater Level Change

Strain Observation Affected by Groundwater-Level Change in Seismic Precursor Monitoring

2016 ◽  
Vol 174 (3) ◽  
pp. 981-996
Author(s):  
Lei Zhang ◽  
Daiyong Cao ◽  
Jingfa Zhang
Keyword(s):  
Groundwater Level ◽  
Level Change ◽  
Seismic Precursor ◽  
Groundwater Level Change

The research of Meinong earthquake induced hydrological anomalies and increased vertical permeability in southwestern Taiwan

2020 ◽  
Author(s):  
Yan-Yao Lin ◽  
Shih-Jung Wang ◽  
Wen-Chi Lai
Keyword(s):  
Groundwater Level ◽  
River Flow ◽  
Large River ◽  
Shallow Aquifer ◽  
Deep Aquifer ◽  
Tidal Analysis ◽  
Level Change ◽  
Vertical Permeability ◽  
Hydrogeological Characteristics ◽  
Groundwater Level Change

<p>Hydrological anomalies induced by the earthquakes are valuable research data to understand the hydrogeology structure. At the same time, a complete hydrogeological data is the key to the study of earthquake hydrology. In this research, we collected the anomalous hydrological data after the M<sub>w</sub> 6.4 2016 Meinong Earthquake in Taiwan. The main purpose is to know the mechanism of hydrological changes triggered by earthquake and understand the local hydrogeological characteristics in the southern Taiwan.</p><p>From the distribution of the groundwater level change in the same location but different depths of aquifer, as well as the location of the rupture and liquefaction, it could be found that the co-seismic groundwater level change is large in Chianan Plain in the northwest of the epicenter and accompanied with a lot of ruptures and liquefactions located along the Hsinhua Fault. However, the observations in several wells around the Hsinhua Fault show a different water level change pattern compared with the other wells in Chianan Plain. Actually, these wells show that the co-seismic groundwater level decreases in the deep aquifer and increase in the shallow aquifer. It is shown that the Meinong Earthquake may enhance the connectivity between different aquifers near the fault zone and produce an increased vertical pressure gradient. The anomalous hydrological phenomenon also reflected in the river flow. Based on the river flow data we collected from five stations in the Zengwun River watershed, the river flow at two stations in the upstream dose not change after earthquake. There is a little increase at the midstream station. However, a large river flow increase is observed at the downstream station. After excluding the influence of rainfall, we think that the large amount of anomalous flow is caused by the rise of the co-seismic groundwater level between the middle and downstream sections, and a large amount of liquefaction in this area can prove this hypothesis.</p><p>The hypothesis of connectivity changes between different aquifers can be verified by analyzing the tidal response of different aquifers. Many studies have used the tide analysis to obtain the aquifer permeability and compressibility, and compared the changes in the analysis results before and after the earthquake. We think that if different aquifers are vertically connected after earthquake, the tidal analysis results should show a consistent permeability. Tidal analysis is executing now and the results will be provided at conference.</p>

scholarly journals Groundwater Level Change Management on Control of Land Subsidence Supported by Borehole Extensometer Compaction Measurements in the Houston-Galveston Region, Texas

Geosciences ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 223 ◽  
Author(s):  
Yi Liu ◽  
Jiang Li ◽  
Zheng N. Fang
Keyword(s):  
Change Management ◽  
Land Subsidence ◽  
Groundwater Level ◽  
Land Surface ◽  
Groundwater Withdrawal ◽  
Overburden Pressure ◽  
Groundwater Levels ◽  
Level Change ◽  
Aquifer Systems ◽  
Groundwater Level Change

As much as 3.05 m of land subsidence was observed in 1979 in the Houston-Galveston region as a result primarily of inelastic compaction of aquitards in the Chicot and Evangeline aquifers between 1937 and 1979. The preconsolidation pressure heads for aquitards within these two aquifers were continuously updated in response to lowering groundwater levels, which in turn was caused by continuously increasing groundwater withdrawal rates from 0.57 to 4.28 million m3/day. This land subsidence occurred without any management of changes in groundwater levels. However, the management of recovering groundwater levels from 1979 to 2000 successfully decreased inelastic compaction from about 40 mm/yr in the early 1980s to zero around 2000 through decreasing groundwater withdrawal rates from 4.3 to 3.0 million m3/day. The inelastic consolidation that had existed for about 63 years roughly from 1937 to 2000 caused a land subsidence hazard in this region. Some rebounding of the land surface was achieved from groundwater level recovering management. It is found in this paper that subsidence of 0.08 to 8.49 mm/yr owing to a pseudo-constant secondary consolidation rate emerged or tended to emerge at 13 borehole extensometer station locations while the groundwater levels in the two aquifers were being managed. It is considered to remain stable in trend since 2000. The subsidence due to the secondary consolidation is beyond the control of any groundwater level change management schemes because it is caused by geo-historical overburden pressure on the two aquifers. The compaction measurements collected from the 13 extensometers since 1971 not only successfully corroborate the need for groundwater level change management in controlling land subsidence but also yield the first empirical findings of the occurrence of secondary consolidation subsidence in the Quaternary and Tertiary aquifer systems in the Houston-Galveston region.

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