We systematically analyze coseismic responses and post-seismic characteristics of groundwater levels in the Three Gorges well-network to the Ms8.0 Wenchuan earthquake on 12 May 2008. The results indicate that these ch...We systematically analyze coseismic responses and post-seismic characteristics of groundwater levels in the Three Gorges well-network to the Ms8.0 Wenchuan earthquake on 12 May 2008. The results indicate that these characteristics differ among wells. On the conditions of similar borehole configurations, the differences are associated with geological structural sites of wells, burial types of aquifers monitored, and transmissivities of aquifer systems. We explored coseismic and post-seismic step-rise and step-drop mechanical mechanisms and their implication to earthquake prediction. We validated the inference that the residual step-rise zone is a possible earthquake risk zone based on recent seismic activity on the Xiannüshan fault in the area.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
基金supportedby Basic Science Research Special Item of the Institute of Geology, China Earthquake Administration (NoDF-IGCEA-0608-2-10)Special Research Program of China Earthquake Administration (No. 200808079).
文摘We systematically analyze coseismic responses and post-seismic characteristics of groundwater levels in the Three Gorges well-network to the Ms8.0 Wenchuan earthquake on 12 May 2008. The results indicate that these characteristics differ among wells. On the conditions of similar borehole configurations, the differences are associated with geological structural sites of wells, burial types of aquifers monitored, and transmissivities of aquifer systems. We explored coseismic and post-seismic step-rise and step-drop mechanical mechanisms and their implication to earthquake prediction. We validated the inference that the residual step-rise zone is a possible earthquake risk zone based on recent seismic activity on the Xiannüshan fault in the area.
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.
