Modelling multi-fissure zones above buried rock ridges in subsiding basins

2021 ◽  
Author(s):  
Li yueting ◽  
Pietro Teatini ◽  
Shujun Ye ◽  
Andrea Franceschini ◽  
Matteo Frigo ◽  
...  
Keyword(s):  
Land Surface ◽  
Sedimentary Basins ◽  
Interface Elements ◽  
Groundwater Exploitation ◽  
Aquifer System ◽  
Sedimentary Sequences ◽  
Earth Fissures ◽  
One Year ◽  
Stress Accumulation ◽  
Maximum Opening

<p>Aseismic earth fissures due to the excessive groundwater exploitation have caused seriously damage in many subsiding sedimentary basins worldwide. Generally, multiple fissures almost parallel to each other with equal distances are prone to develop where a compacting aquifer system overlies impermeable and/or incompressible ridges. Here, an advanced finite-element interface-elements modelling approach is employed to understand this process within unfaulted sedimentary sequences. A simplified geological setting is initially used to investigate the effect of the ridge slope on ruptures behaviors. Then, we reproduce the case of Guangming village, China. In both the proposed scenarios, the model simulates the occurrence of multi-fissures that initiate at land surface and propagate downward, as observed in the sites. The earth fissures are formed as a result of the combination of tensile stress (bending condition) and shear stress (shearing conditions) accumulation around and above the tip and the slopes of the ridge, respectively. The numerical outcomes indicate that the steeper ridge results in higher magnitude stress accumulation above the ridge tip which favors the formation of fissures with significant opening and small or null offset, but at expense of the reduction in stress accumulation area and fissure distribution. In Guangming case, the outcomes show that two ruptures started sliding and only one year later a central fissure opened and propagated down to 15-30 m depth. The simulated maximum opening and sliding of the central and side fissures, respectively, approximate 30 cm, which are almost in agreement with the observations. The numerical results prove that the proposed modeling approach is an effective way to predict and analyze multi-fissure onset and development in subsiding basins.</p>

The Model of Land Surface Movements Induced by Groundwater Rebound in the Area of Former Mining Exploitation

2021 ◽  
Author(s):  
Artur Guzy ◽  
Wojciech Witkowski ◽  
Ryszard Hejmanowski ◽  
Agnieszka Malinowska
Keyword(s):  
Land Surface ◽  
Mine Drainage ◽  
Underground Mining ◽  
Total Duration ◽  
Time Factor ◽  
Land Uplift ◽  
Continuous Increase ◽  
Aquifer System ◽  
Groundwater Head ◽  
Groundwater Rebound

<p>The objective of the research was to investigate the process of rock mass recompaction related to groundwater rebound induced by underground mining. Research has been conducted in the area of the closed copper ore mine (Konrad) as well as the anhydrite and gypsum mine (Lubichów) in south-eastern Poland.</p><p>The mining operation was carried out in the years 1944-2001 in the area of the Konrad mine and 1944-2015 in the area of the Lubichów mine. It resulted in substantial land subsidence of up to 1.4 m and drainage of the aquifer system. However, it is estimated that the subsidence caused by groundwater pumping during these periods was 0.3 m in total. Furthermore, the spatial extent of the depression cone in the aquifer system immediately after the cessation of exploitation significantly exceeded the limits of the mining areas. Following the closure of the mine, a continuous increase in the groundwater head and land uplift is observed.</p><p>Classical survey results and the Persistent Scatter Satellite Radar Interferometry (PSInSAR) method were used to determine land surface movements in the period from November 2015 to November 2020. The results of the research show in the area of the Lubichów mine closed in June 2015, vertical land uplift reached a maximum of approx. 92 mm in that period. At the same time, in the Konrad mine area, closed in March 2001, no significant land uplift was observed. However, the main part of the investigation concerned the development of a novel method of land uplifting prediction. As a result, an attempt was made to comparatively analyze the dynamics of land uplift associated with the life cycle of the mine and the increase in the groundwater head.</p><p>These analyzes allowed the time factor for the modelling of the land uplift to be determined. This time factor is approx. 5 months in the area of the Lubichów mine and indicates that there is a time lag between the start of the groundwater head increase and the land uplift occurrence. Also, the investigation revealed that land uplift will occur in the analyzed area for the next five years. However, the dynamics of such movements will gradually decline in the years to come.</p><p>The methodology developed could be applied to any post-mining area where groundwater rebound-related uplifts are observed. It may be an appropriate tool for estimating both the time during which the land uplift is expected to begin after the mine drainage has been stopped, as well as the total duration of the land uplift phenomena.</p>

Fire regime impacts on post-fire diurnal land surface temperature change over North American boreal forest

2021 ◽  
Author(s):  
Jie Zhao ◽  
Chao Yue ◽  
Philippe Ciais ◽  
Xin Hou ◽  
Qi Tian
Keyword(s):  
Climate Change ◽  
Regression Analysis ◽  
Land Surface ◽  
Fire Regime ◽  
Fire Severity ◽  
Linear Regression Analysis ◽  
Fire Regimes ◽  
Fire Intensity ◽  
Surface Temperature Change ◽  
One Year

<p>Wildfire is the most prevalent natural disturbance in the North American boreal (BNA) forest and can cause post-fire land surface temperature change (ΔLST<sub>fire</sub>) through biophysical processes. Fire regimes, such as fire severity, fire intensity and percentage of burned area (PBA), might affect ΔLST<sub>fire</sub> through their impacts on post-fire vegetation damage. However, the difference of the influence of different fire regimes on the ΔLST<sub>fire</sub> has not been quantified in previous studies, despite ongoing and projected changes in fire regimes in BNA in association with climate change. Here we employed satellite observations and a space-and-time approach to investigate diurnal ΔLST<sub>fire</sub> one year after fire across BNA. We further examined potential impacts of three fire regimes (i.e., fire intensity, fire severity and PBA) and latitude on ΔLST<sub>fire</sub> by simple linear regression analysis and multiple linear regression analysis in a stepwise manner. Our results demonstrated pronounced asymmetry in diurnal ΔLST<sub>fire</sub>, characterized by daytime warming in contrast to nighttime cooling over most BNA. Such diurnal ΔLST<sub>fire</sub> also exhibits a clear latitudinal pattern, with stronger daytime warming and nighttime cooling one year after fire in lower latitudes, whereas in high latitudes fire effects are almost neutral. Among the fire regimes, fire severity accounted for the most (43.65%) of the variation of daytime ΔLST<sub>fire</sub>, followed by PBA (11.6%) and fire intensity (8.5%). The latitude is an important factor affecting the influence of fire regimes on daytime ΔLST<sub>fire</sub>. The sensitivity of fire intensity and PBA impact on daytime ΔLST<sub>fire</sub> decreases with latitude. But only fire severity had a significant effect on nighttime ΔLST<sub>fire</sub> among three fire regimes. Our results highlight important fire regime impacts on daytime ΔLST<sub>fire</sub>, which might play a critical role in catalyzing future boreal climate change through positive feedbacks between fire regime and post-fire surface warming.</p>

scholarly journals Assessment of subsidence risk associated with aquifer storage and recovery in the Coastal Lowlands Aquifer System, Houston, Texas, USA

2020 ◽  
Vol 382 ◽  
pp. 487-491
Author(s):  
Van Kelley ◽  
Michael Turco ◽  
Neil Deeds ◽  
Christina Petersen ◽  
Chris Canonico
Keyword(s):  
Water Supply ◽  
Land Surface ◽  
Future Research ◽  
Aquifer Storage And Recovery ◽  
Aquifer System ◽  
Aquifer Storage ◽  
Alternative Water ◽  
Regulatory Plan ◽  
Insight Into ◽  
Coastal Lowlands

Abstract. In the Houston, Texas region, groundwater use is regulated by the Harris-Galveston Subsidence District (District) because of historical regional subsidence from groundwater development. The District regulates groundwater production in the Coastal Lowlands Aquifer System (CLAS) to mitigate subsidence through the implementation of District Groundwater Regulatory Plan. The District has successfully reduced groundwater pumping as a percent of demand regionally while controlling subsidence through the implementation of alternative water supplies. Aquifer Storage and Recovery (ASR) is an alternative water supply strategy that provides a means to store water underground and increase water supply more cost effectively than traditional storage expansion strategies. Groundwater users in the District are interested in the many potential benefits of ASR as a water supply strategy. Little is known about the potential effects on compaction and land surface subsidence resulting from ASR operations. Recognizing this, the District funded research on the potential subsidence risk associated with ASR. Two hypothetical, though representative, ASR projects were developed and analysed: (1) an industrial ASR project meant to provide water supply during a drought of record (DOR), and (2) a municipal ASR project designed to provide an annual municipal summer peaking water supply. Simulations of groundwater hydraulics and subsidence were performed at three potential locations within the CLAS to provide insight into variability associated with location and aquifer depth. Theoretical simulations confirmed the potential for subsidence associated with the application of ASR in the CLAS, although operating an ASR for summer peaking needs has less potential risk of subsidence than the DOR scenario in the scenarios simulated. The study simulations provide insight into how an ASR project may be designed and operated to minimize compaction and potential subsidence. Based on this study, ASR operated to address summer peaking showed the greatest potential to reduce additional compaction verses sourcing all water from groundwater. This theoretical study provides a basis for future research on subsidence associated with ASR and provides a framework for consideration for the regulation of ASR within the District.

scholarly journals Characterization of earth fissures in South Jiangsu, China

2015 ◽  
Vol 372 ◽  
pp. 249-253 ◽  
Author(s):  
S. Ye ◽  
Y. Wang ◽  
J. Wu ◽  
P. Teatini ◽  
J. Yu ◽  
...  
Keyword(s):  
Land Subsidence ◽  
Earth Fissure ◽  
Aquifer System ◽  
Groundwater Levels ◽  
Earth Fissures ◽  
The Earth ◽  
Cumulative Length ◽  
Differential Land Subsidence

Abstract. The Suzhou-Wuxi-Changzhou (known as "Su-Xi-Chang") area, located in the southern part of Jiangsu Province, China, experienced serious land subsidence caused by overly exploitation of groundwater. The largest cumulative land subsidence has reached 3 m. With the rapid progress of land subsidence since the late 1980s, more than 20 earth fissures developed in Su-Xi-Chang area, although no pre-existing faults have been detected in the surroundings. The mechanisms of earth fissure generation associated with excessive groundwater pumping are: (i) differential land subsidence, (ii) differences in the thickness of the aquifer system, and (iii) bedrock ridges and cliffs at relatively shallow depths. In this study, the Guangming Village Earth Fissures in Wuxi area are selected as a case study to discuss in details the mechanisms of fissure generation. Aquifer exploitation resulted in a drop of groundwater head at a rate of 5–6 m yr−1 in the 1990s, with a cumulative drawdown of 40 m. The first earth fissure at Guangming Village was observed in 1998. The earth fissures, which developed in a zone characterized by a cumulative land subsidence of approximately 800 mm, are located at the flank of a main subsidence bowl with differential subsidence ranging from 0 to 1600 mm in 2001. The maximum differential subsidence rate amounts to 5 mm yr−1 between the two sides of the fissures. The fissure openings range from 30 to 80 mm, with a cumulative length of 1000 m. Depth of bed rock changes from 60 to 140 m across the earth fissure. The causes of earth fissure generation at Guangming Village includes a decrease in groundwater levels, differences in the thickness of aquifer system, shallow depths of bedrock ridges and cliffs, and subsequent differential land subsidence.

scholarly journals Geology and Aquifer Sensitivity of Quaternary Glacial Deposits Overlying a Portion of the Mahomet Buried Bedrock Valley Aquifer System

Hydrology ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 69
Author(s):  
Andrew Watson ◽  
Eric W. Peterson ◽  
Dave Malone ◽  
Lisa Tranel
Keyword(s):  
Land Surface ◽  
Late Quaternary ◽  
Geologic Mapping ◽  
Quaternary Deposits ◽  
Aquifer System ◽  
Geologic Materials ◽  
Lithostratigraphic Units ◽  
Glacial Outwash ◽  
Aquifer Sensitivity ◽  
Geologic Data

To characterize the distribution of Holocene and Late Quaternary deposits and to assess the contamination potential of the Mahomet Aquifer, surficial geologic and aquifer sensitivity maps of the Gibson City East 7.5-Minute Quadrangle were created. Geologic data, extent, and thickness of the geologic materials were coupled with LiDAR topographic data and analyzed using ESRI’s ArcGIS 10.6.1. Aquifer sensitivity to contamination was calculated based on the depth to the first aquifer unit, aquifer thickness, and the lithology of the aquifer materials. The surficial geologic mapping identified five lithostratigraphic units: the Cahokia Formation, the Equality Formation, the Henry Formation, and the Yorkville and Batestown Members of the Lemont Formation. The southeast to northwest trending Illiana Morainic System is the most prominent feature in the study area and delineates the maximum extent of the glaciers during the Livingston Phase of glaciation. Postglacial deposits of the Cahokia Formation, alluvium, interfinger, and overlie with glacial outwash of the Henry Formation along channels and drainage ways downslope of the moraine. The areas of least sensitivity are located over the Illiana Morainic System, whereas the greatest potential to contamination occurs where the thickest deposits of the Henry Formation and Cahokia Formation lie at or just below the land surface.

scholarly journals Intrusion of Saline Water into a Coastal Aquifer Containing Palaeogroundwater in the Viimsi Peninsula in Estonia

Geosciences ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 47
Author(s):  
Valle Raidla ◽  
Joonas Pärn ◽  
Werner Aeschbach ◽  
György Czuppon ◽  
Jüri Ivask ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Seawater Intrusion ◽  
Saline Water ◽  
Sole Source ◽  
Crystalline Basement ◽  
Monitoring Networks ◽  
Radium Isotopes ◽  
Groundwater Exploitation ◽  
Aquifer System ◽  
North East

The Viimsi peninsula is located north-east of Tallinn, capital of Estonia. The Cambrian-Vendian (Cm-V) aquifer system is a sole source of drinking water in the area. Historically, the groundwater exploitation has led to freshening of groundwater in the peninsula, but in recent years an increase in chloride concentrations and enrichment in δ18O values has been detected, but in recent years hydrochemical parameters indicate an increasing influence of a saline water source. The exact origin of this saline water has remained unclear. The aim of the current study is to elucidate whether the increase in Cl− concentrations is related to seawater intrusion or to the infiltration of saline water from the underlying crystalline basement. To identify the source of salinity, chemical composition of the groundwater and the isotope tracers (e.g., δ18O and radium isotopes) were studied in the Viimsi peninsula in the period from 1987 to 2018. Our results show that chemical composition of Cm-V groundwater in the peninsula is clearly controlled by three-component mixing between glacial palaeogroundwater, saline water from the underling crystalline basement and modern meteoric water. The concentrations of Ra are also significantly affected by the mixing, but the spatial variation of radium isotopes (226Ra and 228Ra) suggests the widespread occurrence of the U in the surrounding sedimentary sequence. Our hypothesis is that, in addition to U originating from the crystalline basement, some U could be associated with secondary U deposits in sedimentary rocks. The formation of these secondary U deposits could be related to glacial meltwater intrusion in the Pleistocene. Although the results suggest that the infiltration of saline groundwater from the underlying crystalline basement as the main source of salinity in the study area, the risk of seawater intrusion in the future cannot be ruled out. It needs to be highlighted that the present groundwater monitoring networks may not be precise enough to detect the potential seawater intrusion and subsequent changes in water quality of the Cm-V aquifer system in the Viimsi peninsula.

scholarly journals Understanding the dynamic behaviour for the Madrid aquifer (Spain): insights from the integration of A-DInSAR and 3-D groundwater flow and geomechanical models

2020 ◽  
Vol 382 ◽  
pp. 409-414 ◽  
Author(s):  
Roberta Bonì ◽  
Claudia Meisina ◽  
Pietro Teatini ◽  
Francesco Zucca ◽  
Claudia Zoccarato ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
Land Surface ◽  
Dynamic Behaviour ◽  
Time Lag ◽  
Integrated Approach ◽  
Groundwater Withdrawal ◽  
System Response ◽  
Interferometric Synthetic Aperture Radar ◽  
Geomechanical Model ◽  
Aquifer System

Abstract. Advanced Differential Interferometric Synthetic Aperture Radar (A-DInSAR) techniques and 3-D groundwater flow and geomechanical models are integrated to improve our knowledge about the Tertiary detritic aquifer of Madrid (TDAM). In particular, the attention is focused on the Manzanares-Jarama well field, located to the northwest of Madrid, which experienced five cycles of extensive groundwater withdrawal followed by natural recovery, to cope with the droughts occurred in summer 1995, 1999, 2002, 2006, and 2009. Piezometric records and A-DInSAR data acquired by ERS-1/2 and ENVISAT satellites during the periods 1992–2000 and 2002–2010, respectively, have been used to calibrate the groundwater flow and the geomechanical models. A time-lag of about one month between the hydraulic head changes and the displacements of the land surface has been detected by a joint wavelet analysis of A-DInSAR and piezometer head time series. Overall, the results show the effectiveness of the proposed integrated approach composed of A-DInSAR and 3-D geomechanical model to characterize the aquifer-system response during and after the groundwater withdrawal.

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