An earthquake with Ms5.8 occurred on 10 March 2011 in Yingjiang county, western Yunnan, China. This earthquake caused 25 deaths and over 250 injuries. In order to better understand the seismotectonics in the region, w...An earthquake with Ms5.8 occurred on 10 March 2011 in Yingjiang county, western Yunnan, China. This earthquake caused 25 deaths and over 250 injuries. In order to better understand the seismotectonics in the region, we collected the arrival time data from the Yunnan seismic observational bulletins during 1 January to 25 March 2011, and precisely hand-picked the arrival times from high-quality seismograms that were recorded by the temporary seismic stations deployed by our Institute of Crustal Dynamics, China Earthquake Administration. Using these arrival times, we relocated all the earthquakes including the Yingjiang mainshock and its aftershocks using the double-difference relocation algorithm. Our results show that the relocated earthquakes dominantly occurred along the ENE direction and formed an upside-down bow-shaped structure in depth. It is also observed that after the Yingjiang mainshock, some aftershocks extended toward the SSE over about 10 km. These results may indicate that the Yingjiang mainshock ruptured a conjugate fault system consisting of the ENE trending Da Yingjiang fault and a SSE trending blind fault. Such structural features could contribute to severely seismic hazards during the moderate-size Yingjiang earthquake.展开更多
In the southern South-North Seismic Zone,China,seismic activity in the Yingjiang area of western Yunnan increased from December 2010,and eventually a destructive earthquake of Ms5.9 occurred near Yingjiang town on 10 ...In the southern South-North Seismic Zone,China,seismic activity in the Yingjiang area of western Yunnan increased from December 2010,and eventually a destructive earthquake of Ms5.9 occurred near Yingjiang town on 10 March 2011.The focal mechanism and hypocenter location of the mainshock suggest that the Dayingjiang Fault was the site of the mainshock rupture.However,most of foreshocks and all aftershocks recorded by a portable seismic array located close to the mainshock occurred along the N-S-striking Sudian Fault,indicating that this fault had an important influence on these shocks.Coulomb stress calculations show that three strong （magnitude ≥5.0） earthquakes that occurred in the study region in 2008 increased the coulomb stress along the plane parallel to the Dayingjiang Fault.This supports the Dayingjiang Fault,and not the Sudian Fault,as the seismogenic fault of the 2011 Ms5.9 Yingjiang earthquake.The strong earthquakes in 2008 also increased the Coulomb stress at depths of ≤5 km along the entire Sudian Fault,and by doing so increased the shallow seismic activity along the fault.This explains why the foreshocks and aftershocks of the 2011 Yingjiang earthquake were located mostly on the Sudian Fault where it cuts the shallow crust.The earthquakes at the intersection of the Sudian and Dayingjiang faults are distributed mainly along a belt that dips to the southeast at ～40°,suggesting that the Dayingjiang Fault in the mainshock area also dips to the southeast at ～40°.展开更多
Geothermal resource,a green and sustainable energy resource,plays an important role in achieving‘emission peak’and‘carbon neutrality’targets.The Yingjiang Basin is located in the eastern branch of the Mediterranea...Geothermal resource,a green and sustainable energy resource,plays an important role in achieving‘emission peak’and‘carbon neutrality’targets.The Yingjiang Basin is located in the eastern branch of the Mediterranean-Himalayan high-temperature geothermal belt and exhibits considerable potential for geothermal resources.However,current investigations into the distribution of deep geothermal resources in this region are somewhat limited.In this paper,the transient plane source(TPS)method is used to measure the thermal conductivity parameters of 31 rock samples within the study area.Additionally,the one-dimensional steady-state heat conduction equation is employed to calculate the deep geothermal field,considering the constraints of rock thermal properties and terrestrial heat flow in the study area.Furthermore,the“stripping method”is used to determine the contribution rate of sedimentary layer to terrestrial heat flow,while the volume method is applied to estimate the geothermal resources at burial depths of 3000-5000 m.The results show that(1)The heat generation rate of granite is the highest with an average value of 4.52 mW/m^(3),followed by gneiss with an average value in the range of 2.0-3.5 W/(m·K),mudstone and sandstone being the lowest with an average value between 1.0 and 2.0 W/(m·K).(2)The main contributor of terrestrial heat flow in the study area is mantle heat flow,and the contribution of sedimentary layers to terrestrial heat flow only accounts for about 2%.(3)The geothermal resources in Yingjiang Basin within the depth range of 3000-5000 m is 93.6×10^(15)kJ,or 3.2×10^(9)tonnes standard coal equivalent(SCE).展开更多
Significant anomalies were observed at the geomagnetic stations in the southwest region of China before the Yingjiang M_S6. 1 earthquake and the Ludian M_S6. 5 earthquake in 2014.We processed the geomagnetic vertical ...Significant anomalies were observed at the geomagnetic stations in the southwest region of China before the Yingjiang M_S6. 1 earthquake and the Ludian M_S6. 5 earthquake in 2014.We processed the geomagnetic vertical component diurnal variation data by the spatial correlation method. The results show that during the period from April 1 to May 20,2014,there existed quasi-synchronous decrease changes in the coefficient curves between the five geomagnetic stations of Guiyang,Hechi,Nanshan,Muli,Yongning and Xinyi and Hongshan stations. Furthermore,there was a high gradient zone in the normalized correlation coefficient contour map with background values removed. The epicenters of the Yingjiang M_S6. 1 earthquake and the Ludian M_S6. 5 earthquake are located in the gradient zone or near the gradient zone.展开更多
DEAR EDITOR, The sun bear, Helarctos malayanus （Raffles, 1821）, is a forest- dependent bear species distributed in tropical Southeast Asia. The species was previously reported from scattered localities in southweste...DEAR EDITOR, The sun bear, Helarctos malayanus （Raffles, 1821）, is a forest- dependent bear species distributed in tropical Southeast Asia. The species was previously reported from scattered localities in southwestern China, which is at the northeastern edge of its global range. Due to the scarcity of reliable recent records, some authorities cast doubt on the continued existence of sun bear in China. Here we present the rediscovery of this species in Yingjiang County, western Yunnan Province, China, near the international border with Myanmar＇s Kachin State.展开更多
基金supported by National Natural Science Foundation of China(Nos.40974201 and 40774044)to J.Lei
文摘An earthquake with Ms5.8 occurred on 10 March 2011 in Yingjiang county, western Yunnan, China. This earthquake caused 25 deaths and over 250 injuries. In order to better understand the seismotectonics in the region, we collected the arrival time data from the Yunnan seismic observational bulletins during 1 January to 25 March 2011, and precisely hand-picked the arrival times from high-quality seismograms that were recorded by the temporary seismic stations deployed by our Institute of Crustal Dynamics, China Earthquake Administration. Using these arrival times, we relocated all the earthquakes including the Yingjiang mainshock and its aftershocks using the double-difference relocation algorithm. Our results show that the relocated earthquakes dominantly occurred along the ENE direction and formed an upside-down bow-shaped structure in depth. It is also observed that after the Yingjiang mainshock, some aftershocks extended toward the SSE over about 10 km. These results may indicate that the Yingjiang mainshock ruptured a conjugate fault system consisting of the ENE trending Da Yingjiang fault and a SSE trending blind fault. Such structural features could contribute to severely seismic hazards during the moderate-size Yingjiang earthquake.
基金supported by the National Natural Science Foundation of China (NSFC-41174039)the China Geological Survey
文摘In the southern South-North Seismic Zone,China,seismic activity in the Yingjiang area of western Yunnan increased from December 2010,and eventually a destructive earthquake of Ms5.9 occurred near Yingjiang town on 10 March 2011.The focal mechanism and hypocenter location of the mainshock suggest that the Dayingjiang Fault was the site of the mainshock rupture.However,most of foreshocks and all aftershocks recorded by a portable seismic array located close to the mainshock occurred along the N-S-striking Sudian Fault,indicating that this fault had an important influence on these shocks.Coulomb stress calculations show that three strong （magnitude ≥5.0） earthquakes that occurred in the study region in 2008 increased the coulomb stress along the plane parallel to the Dayingjiang Fault.This supports the Dayingjiang Fault,and not the Sudian Fault,as the seismogenic fault of the 2011 Ms5.9 Yingjiang earthquake.The strong earthquakes in 2008 also increased the Coulomb stress at depths of ≤5 km along the entire Sudian Fault,and by doing so increased the shallow seismic activity along the fault.This explains why the foreshocks and aftershocks of the 2011 Yingjiang earthquake were located mostly on the Sudian Fault where it cuts the shallow crust.The earthquakes at the intersection of the Sudian and Dayingjiang faults are distributed mainly along a belt that dips to the southeast at ～40°,suggesting that the Dayingjiang Fault in the mainshock area also dips to the southeast at ～40°.
文摘Geothermal resource,a green and sustainable energy resource,plays an important role in achieving‘emission peak’and‘carbon neutrality’targets.The Yingjiang Basin is located in the eastern branch of the Mediterranean-Himalayan high-temperature geothermal belt and exhibits considerable potential for geothermal resources.However,current investigations into the distribution of deep geothermal resources in this region are somewhat limited.In this paper,the transient plane source(TPS)method is used to measure the thermal conductivity parameters of 31 rock samples within the study area.Additionally,the one-dimensional steady-state heat conduction equation is employed to calculate the deep geothermal field,considering the constraints of rock thermal properties and terrestrial heat flow in the study area.Furthermore,the“stripping method”is used to determine the contribution rate of sedimentary layer to terrestrial heat flow,while the volume method is applied to estimate the geothermal resources at burial depths of 3000-5000 m.The results show that(1)The heat generation rate of granite is the highest with an average value of 4.52 mW/m^(3),followed by gneiss with an average value in the range of 2.0-3.5 W/(m·K),mudstone and sandstone being the lowest with an average value between 1.0 and 2.0 W/(m·K).(2)The main contributor of terrestrial heat flow in the study area is mantle heat flow,and the contribution of sedimentary layers to terrestrial heat flow only accounts for about 2%.(3)The geothermal resources in Yingjiang Basin within the depth range of 3000-5000 m is 93.6×10^(15)kJ,or 3.2×10^(9)tonnes standard coal equivalent(SCE).
基金sponsored by the Spark Program for Earthquake Science and Technology,China Earthquake Administration(Serial No.XH17010Y)the Seismic Tracking and Orientation Task,China Earthquake Administration(Serial No.2018010401)Major Scientific and Technical Project of Science and Technology Department of Inner Mongolia in 2016(Strong Earthquake Track in the Short Stage and Integration Innovation of Stereoscopic Observation Technology in Space and Ground)
文摘Significant anomalies were observed at the geomagnetic stations in the southwest region of China before the Yingjiang M_S6. 1 earthquake and the Ludian M_S6. 5 earthquake in 2014.We processed the geomagnetic vertical component diurnal variation data by the spatial correlation method. The results show that during the period from April 1 to May 20,2014,there existed quasi-synchronous decrease changes in the coefficient curves between the five geomagnetic stations of Guiyang,Hechi,Nanshan,Muli,Yongning and Xinyi and Hongshan stations. Furthermore,there was a high gradient zone in the normalized correlation coefficient contour map with background values removed. The epicenters of the Yingjiang M_S6. 1 earthquake and the Ludian M_S6. 5 earthquake are located in the gradient zone or near the gradient zone.
基金the Yingjiang County Propaganda Departmentthe Forestry Bureau
文摘DEAR EDITOR, The sun bear, Helarctos malayanus （Raffles, 1821）, is a forest- dependent bear species distributed in tropical Southeast Asia. The species was previously reported from scattered localities in southwestern China, which is at the northeastern edge of its global range. Due to the scarcity of reliable recent records, some authorities cast doubt on the continued existence of sun bear in China. Here we present the rediscovery of this species in Yingjiang County, western Yunnan Province, China, near the international border with Myanmar＇s Kachin State.
