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 se...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
This paper discusses technical requirements for location selection,structure design,and drilling of groundwater monitoring wells for earthquake studies on the bases of national and earthquake-prediction specific techn...This paper discusses technical requirements for location selection,structure design,and drilling of groundwater monitoring wells for earthquake studies on the bases of national and earthquake-prediction specific technical standards as well as practical experience from construction of such wells.展开更多
Using the ATG-6138 mercury detector recently developed by the Hangzhou Aadtech Co.Ltd.,a record of the co-seismic effect of mercury(Hg)vapor accompanying the 2015 Nepal M_S8.1 earthquake was obtained in the Mile monit...Using the ATG-6138 mercury detector recently developed by the Hangzhou Aadtech Co.Ltd.,a record of the co-seismic effect of mercury(Hg)vapor accompanying the 2015 Nepal M_S8.1 earthquake was obtained in the Mile monitoring well,Yunnan Province.This is the first record of co-seismic effect obtained by mercury vapor observation in China.Such a fact implies that it would be possible to record more information about crustal dynamic effects,such as solid tide,co-seismic effect,etc.,by further improving observation instrument precision and increasing the sampling frequency of the chemical quantity of subsurface fluids.This may help us to raise the capability of earthquake precursor monitoring and forecasting in the future.展开更多
Fine measurements have been conducted to temperatures and their gradients of six wells of the Jinsha River Groundwater Observational Network.The results show that the influence depths of sun radiation heat are 50m to ...Fine measurements have been conducted to temperatures and their gradients of six wells of the Jinsha River Groundwater Observational Network.The results show that the influence depths of sun radiation heat are 50m to 125m,average temperature gradients in the wells range from 0.11 to 2.81℃/hm and most are 1～2℃/hm,and the temperature gradients on varied depth sections of one well are highly changeable.Lithology of strata and their integrity,particularly high-angle crashed fault zones,have imposed major effects on the influence depths of sun radiation heat and temperature gradients of the wells.The micro dynamic characteristics of water temperature,such as coseismic effects,tidal effects and anomalies of the wells prior to earthquakes,probably depend,to a large degree,on the temperature gradients of the depths at which the water temperature sensors are settled.展开更多
In this paper,based on the collected data and earthquake field investigation,characteristics of the MS4.1 Hujiaping earthquake of November 22,2008 at Guizhou town in Zigui county,Hubei Province and the geological and ...In this paper,based on the collected data and earthquake field investigation,characteristics of the MS4.1 Hujiaping earthquake of November 22,2008 at Guizhou town in Zigui county,Hubei Province and the geological and hydrogeological conditions and seismicity background of the area are analyzed,and the earthquake disaster is presented. Some scientific issues relating to earthquake precursors and the cause of the earthquake is discussed. The authors consider that the earthquake is a tectonic type reservoir-induced earthquake,occurring along the Xiannvshan fault under the joint action of reservoir water loading and water infiltration,and that there were certain suspected anomalies appearing in the gravity field before the earthquake. The cause of the earthquake may also be related to the effect of the Wenchuan earthquake on the local stress field.展开更多
A groundwater observational network for monitoring seismic precursors has been established at the reservoirs on the lower reaches of the Jinsha River in southwestern China, where a series of hydropower stations are un...A groundwater observational network for monitoring seismic precursors has been established at the reservoirs on the lower reaches of the Jinsha River in southwestern China, where a series of hydropower stations are under construction. It is the second network in China that is operated by enterprises with the purpose to observe and study earthquake precursors in reservoir areas. This paper presents the layout and technical constitution of the network, features of its observational wells and aquifers and the preliminary result of its experimental operation. Its capability to monitor seismic precursor is evaluated based on an analysis of the well-aquifer system as well as the multiple-monthly, monthly, daily and hourly variations of water levels and water temperatures observed by this network.展开更多
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sponsored by the Program of China Earthquake Administration(2200404)
文摘This paper discusses technical requirements for location selection,structure design,and drilling of groundwater monitoring wells for earthquake studies on the bases of national and earthquake-prediction specific technical standards as well as practical experience from construction of such wells.
基金sponsored by the Earthquake Science and Technology Spark Plan,China (XH15041Y)
文摘Using the ATG-6138 mercury detector recently developed by the Hangzhou Aadtech Co.Ltd.,a record of the co-seismic effect of mercury(Hg)vapor accompanying the 2015 Nepal M_S8.1 earthquake was obtained in the Mile monitoring well,Yunnan Province.This is the first record of co-seismic effect obtained by mercury vapor observation in China.Such a fact implies that it would be possible to record more information about crustal dynamic effects,such as solid tide,co-seismic effect,etc.,by further improving observation instrument precision and increasing the sampling frequency of the chemical quantity of subsurface fluids.This may help us to raise the capability of earthquake precursor monitoring and forecasting in the future.
基金supported by the Jinsha River Development Corporation Limited,China Yangtze Three Gorge Engineering Development Group(JSJ(06)-007)
文摘Fine measurements have been conducted to temperatures and their gradients of six wells of the Jinsha River Groundwater Observational Network.The results show that the influence depths of sun radiation heat are 50m to 125m,average temperature gradients in the wells range from 0.11 to 2.81℃/hm and most are 1～2℃/hm,and the temperature gradients on varied depth sections of one well are highly changeable.Lithology of strata and their integrity,particularly high-angle crashed fault zones,have imposed major effects on the influence depths of sun radiation heat and temperature gradients of the wells.The micro dynamic characteristics of water temperature,such as coseismic effects,tidal effects and anomalies of the wells prior to earthquakes,probably depend,to a large degree,on the temperature gradients of the depths at which the water temperature sensors are settled.
文摘In this paper,based on the collected data and earthquake field investigation,characteristics of the MS4.1 Hujiaping earthquake of November 22,2008 at Guizhou town in Zigui county,Hubei Province and the geological and hydrogeological conditions and seismicity background of the area are analyzed,and the earthquake disaster is presented. Some scientific issues relating to earthquake precursors and the cause of the earthquake is discussed. The authors consider that the earthquake is a tectonic type reservoir-induced earthquake,occurring along the Xiannvshan fault under the joint action of reservoir water loading and water infiltration,and that there were certain suspected anomalies appearing in the gravity field before the earthquake. The cause of the earthquake may also be related to the effect of the Wenchuan earthquake on the local stress field.
基金sponsored by the Jinsha River Development Corporation Ltd. Program of China Three Gorges Cooperation (JSJ(06)007)
文摘A groundwater observational network for monitoring seismic precursors has been established at the reservoirs on the lower reaches of the Jinsha River in southwestern China, where a series of hydropower stations are under construction. It is the second network in China that is operated by enterprises with the purpose to observe and study earthquake precursors in reservoir areas. This paper presents the layout and technical constitution of the network, features of its observational wells and aquifers and the preliminary result of its experimental operation. Its capability to monitor seismic precursor is evaluated based on an analysis of the well-aquifer system as well as the multiple-monthly, monthly, daily and hourly variations of water levels and water temperatures observed by this network.
