Earthquake-related hydrochemical changes in thermal springs have been widely observed;however,quantitative modeling of the reactive transport process is absent.In the present study,we apply reactive transport simulati...Earthquake-related hydrochemical changes in thermal springs have been widely observed;however,quantitative modeling of the reactive transport process is absent.In the present study,we apply reactive transport simulation to capture the hydrochemical responses in a thermal spring following the Wenchuan Ms 8.0 and Lushan Ms 7.0 earthquakes.We first constrain deep reservoir geothermal fluid compositions and temperature by multicomponent geothermometry,and then a reactive geochemical transport model is constructed to reproduce the hydrochemical evolution process.The results show that the recharge from the shallow aquifer increases gradually until it reaches a peak because of the permeability enhancement caused by the Lushan earthquake,which may be the mechanism to explain the earthquake-related hydrochemical responses.In contrast to the postseismic effect of the Wenchuan earthquake,the chemical evolution can be considered as hydrochemical anomalies related to the Lushan earthquake.This study proves that the efficient simulation of reactive transport processes is useful for investigating earthquake-related signals in hydrochemical time series.展开更多
古堆-南梁泉域位于山西省南部,是一个深循环与浅循环共存、冷水系统与热水系统循环转化、多级次排泄的复合型岩溶水系统,因长期不合理的开发利用,泉域内出现了一系列岩溶水环境地质问题。以水文地质调查工作为基础,综合采用地下水流场...古堆-南梁泉域位于山西省南部,是一个深循环与浅循环共存、冷水系统与热水系统循环转化、多级次排泄的复合型岩溶水系统,因长期不合理的开发利用,泉域内出现了一系列岩溶水环境地质问题。以水文地质调查工作为基础,综合采用地下水流场对比分析、水文地球化学及同位素分析、岩溶水资源评价等方法,详细论述了古堆-南梁泉域内岩溶水环境问题现状及其成因,并提出了泉源区生态修复与规划方案。结果表明:受气候变化与人类活动的叠加影响,系统内古堆泉、南梁泉、海头泉分别于1999年、1992年、2002年断流,2013-2021年区域地下水位平均下降速度达2.53 m/a;水化学、同位素分析结果指示了排泄区九原山附近松散岩类孔隙水越流补给量、三泉水库渗漏补给量对岩溶地下水的影响已不可忽略;泉域内岩溶水超Ⅲ类水水质标准样品占比由2014年的62.5%升高至2021年的81.25%;泉源区0.904 km 2范围可细分为核心保护区、水库蓄水区、一般保护区,应分区进行生态保护与修复规划。研究结果可为山西省超采区综合治理、古堆泉水生态修复与保护工作提供基础依据。展开更多
Water flow from an artesian well stopped on December 17,2007 but recovered when the Wenchuan Ms 8.0 earthquake occurred on May 12,2008.This well is located 90 km south of the epicenter in an extensional tectonic setti...Water flow from an artesian well stopped on December 17,2007 but recovered when the Wenchuan Ms 8.0 earthquake occurred on May 12,2008.This well is located 90 km south of the epicenter in an extensional tectonic setting,where similar changes of water level and resistivity were observed at two other nearby sites.Our investigation suggests that this phenomenon was not caused by environmental disturbances,such as drought or borehole-drilling activity,but might be a precursor to the earthquake.展开更多
The 12 May 2008 Ms 8.0 Wenchuan earthquake caused notable changes in the water levels of wells in the Three Gorges area. This work examines the relationship between these coseismic changes in water level and the chang...The 12 May 2008 Ms 8.0 Wenchuan earthquake caused notable changes in the water levels of wells in the Three Gorges area. This work examines the relationship between these coseismic changes in water level and the changes in aquifer parameters. Three wells in the area with good responses to earth tide were chosen for analysis. Water-level data from February to June 2008 were used to calculate the aquifer transmissivity, permeability and specific storage of the rocks, and analyze the relationship between the coseismic responses of the wells and their aquifer parameters. The results show that the Wenchuan earthquake changed these parameters considerably, thereby controlling co- and postseismic variations of water level. The values of these parameters prior to the earthquake are linearly related with the amplitudes of coseismic variations in water level. The larger the aquifer transmissivity, the more remarkable the coseismic change in water level. During the earthquake, changes in aquifer parameters were found to be associated with coseismic variations in water level, with the larger changes occurring when the coseismic variation in water level was larger. The tectonic setting has a certain degree of influence on the co- and postseismic changes in water level. The permeability structures of the fault zone appear to determine the manner of coseismic variation in water level. Moreover, it seems that the water level in wells where groundwater converges more easily can recover faster following an earthquake. Insight from this study helps to improve understanding of the characteristics of water-level changes caused by earthquakes.展开更多
This work focuses on variations of the Earth tidal factor and phase lag derived from groundwater observations before and after major earthquakes.It is based on an analysis of the data from four observational wells at ...This work focuses on variations of the Earth tidal factor and phase lag derived from groundwater observations before and after major earthquakes.It is based on an analysis of the data from four observational wells at boundaries between distinct active blocks of China mainland.These wells are also situated on several active fault zones and have exhibited considerable responses to the Wenchuan Ms8.0 earthquake of 2008 in China.We collected hourly records of water levels of these wells from 2007to 2009 and processed these data for analysis.The tidal factors,phase lags,and phase-difference changes of tidal residuals of each well were calculated.We found that when the Wenchuan quake happened,the tidal factors of the 4 wells were changing rapidly,while their phase lags and phase differences of tidal residuals declined swiftly,which may reflect the stress and strain changes of the well-aquifer system during the seismic generation.展开更多
基金supported by the National Key R&D Program of China(Grant No.2023YFC3209700)the National Natural Science Foundation of China(Grant Nos.41807194,41902263,41807208).
文摘Earthquake-related hydrochemical changes in thermal springs have been widely observed;however,quantitative modeling of the reactive transport process is absent.In the present study,we apply reactive transport simulation to capture the hydrochemical responses in a thermal spring following the Wenchuan Ms 8.0 and Lushan Ms 7.0 earthquakes.We first constrain deep reservoir geothermal fluid compositions and temperature by multicomponent geothermometry,and then a reactive geochemical transport model is constructed to reproduce the hydrochemical evolution process.The results show that the recharge from the shallow aquifer increases gradually until it reaches a peak because of the permeability enhancement caused by the Lushan earthquake,which may be the mechanism to explain the earthquake-related hydrochemical responses.In contrast to the postseismic effect of the Wenchuan earthquake,the chemical evolution can be considered as hydrochemical anomalies related to the Lushan earthquake.This study proves that the efficient simulation of reactive transport processes is useful for investigating earthquake-related signals in hydrochemical time series.
文摘古堆-南梁泉域位于山西省南部,是一个深循环与浅循环共存、冷水系统与热水系统循环转化、多级次排泄的复合型岩溶水系统,因长期不合理的开发利用,泉域内出现了一系列岩溶水环境地质问题。以水文地质调查工作为基础,综合采用地下水流场对比分析、水文地球化学及同位素分析、岩溶水资源评价等方法,详细论述了古堆-南梁泉域内岩溶水环境问题现状及其成因,并提出了泉源区生态修复与规划方案。结果表明:受气候变化与人类活动的叠加影响,系统内古堆泉、南梁泉、海头泉分别于1999年、1992年、2002年断流,2013-2021年区域地下水位平均下降速度达2.53 m/a;水化学、同位素分析结果指示了排泄区九原山附近松散岩类孔隙水越流补给量、三泉水库渗漏补给量对岩溶地下水的影响已不可忽略;泉域内岩溶水超Ⅲ类水水质标准样品占比由2014年的62.5%升高至2021年的81.25%;泉源区0.904 km 2范围可细分为核心保护区、水库蓄水区、一般保护区,应分区进行生态保护与修复规划。研究结果可为山西省超采区综合治理、古堆泉水生态修复与保护工作提供基础依据。
基金supported by the National Natural Science Foundation ofChina(40930637)Basic Science Research Special Item of the Instituteof Geology,China Earthquake Administration(DF-IGCEA-0608210)Special Research Program of China Earthquake Administration(200808079)
文摘Water flow from an artesian well stopped on December 17,2007 but recovered when the Wenchuan Ms 8.0 earthquake occurred on May 12,2008.This well is located 90 km south of the epicenter in an extensional tectonic setting,where similar changes of water level and resistivity were observed at two other nearby sites.Our investigation suggests that this phenomenon was not caused by environmental disturbances,such as drought or borehole-drilling activity,but might be a precursor to the earthquake.
基金supported by the National Natural Science Foundation of China (40930637)the Special Project for Earthquake Science (200808079)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China (20100022110001)a Special Project of the Seismological Community (IGCEA-1205)
文摘The 12 May 2008 Ms 8.0 Wenchuan earthquake caused notable changes in the water levels of wells in the Three Gorges area. This work examines the relationship between these coseismic changes in water level and the changes in aquifer parameters. Three wells in the area with good responses to earth tide were chosen for analysis. Water-level data from February to June 2008 were used to calculate the aquifer transmissivity, permeability and specific storage of the rocks, and analyze the relationship between the coseismic responses of the wells and their aquifer parameters. The results show that the Wenchuan earthquake changed these parameters considerably, thereby controlling co- and postseismic variations of water level. The values of these parameters prior to the earthquake are linearly related with the amplitudes of coseismic variations in water level. The larger the aquifer transmissivity, the more remarkable the coseismic change in water level. During the earthquake, changes in aquifer parameters were found to be associated with coseismic variations in water level, with the larger changes occurring when the coseismic variation in water level was larger. The tectonic setting has a certain degree of influence on the co- and postseismic changes in water level. The permeability structures of the fault zone appear to determine the manner of coseismic variation in water level. Moreover, it seems that the water level in wells where groundwater converges more easily can recover faster following an earthquake. Insight from this study helps to improve understanding of the characteristics of water-level changes caused by earthquakes.
基金supported by National Natural Science Foundation of China(Grant No.40930637)Special Project for Earthquake Science(Grant No.200808079)Subject Foundation of Ministry of Education for Doctor Candidates in Universities(Grant No.20100022110001)
文摘This work focuses on variations of the Earth tidal factor and phase lag derived from groundwater observations before and after major earthquakes.It is based on an analysis of the data from four observational wells at boundaries between distinct active blocks of China mainland.These wells are also situated on several active fault zones and have exhibited considerable responses to the Wenchuan Ms8.0 earthquake of 2008 in China.We collected hourly records of water levels of these wells from 2007to 2009 and processed these data for analysis.The tidal factors,phase lags,and phase-difference changes of tidal residuals of each well were calculated.We found that when the Wenchuan quake happened,the tidal factors of the 4 wells were changing rapidly,while their phase lags and phase differences of tidal residuals declined swiftly,which may reflect the stress and strain changes of the well-aquifer system during the seismic generation.
