The aim of this investigation is to find possible changes in ultra-deep earthquakes (UDQ) during different seasons of the year. In the acquisition of data for our previous work we observed an inexplicable pattern of g...The aim of this investigation is to find possible changes in ultra-deep earthquakes (UDQ) during different seasons of the year. In the acquisition of data for our previous work we observed an inexplicable pattern of growth of ultra-deep tremors (UDQ) during the studied period. Apparently, there is no viable explanation for growth occurring at such a level, presumably in the asthenosphere. Current research and theories developed for the inner layers of the Earth do not explain such variations. Therefore, a possible explanation would be in external factors such as the seasons of the year, which are determined by changes in the Earth’s axial tilt, and therefore the portion of the earth that is angled toward the sun. This paper focuses exclusively on UDQ events. To simplify the calculations, we consider four main locations;this includes one more region than our previous paper but includes only UDQ data. The results showed that during spring and autumn UDQ events grew slightly in both Northern and Southern Hemispheres. It is also suggested that a contributor to UDQ events is friction from the subducting lithosphere against the continental plates.展开更多
In early February,2023,southeastern Türkiye and northern Syria were hit by a series of deadly earthquakes(two of them above magnitude 7.5)that are proving to be one of the most significant earthquake disasters of...In early February,2023,southeastern Türkiye and northern Syria were hit by a series of deadly earthquakes(two of them above magnitude 7.5)that are proving to be one of the most significant earthquake disasters of this century.These“twin quakes”caused a large number of casualties and property losses.As of press time,the death toll in Türkiye and Syria has surpassed 51000 and the number of injured has surpassed 120000,with the number affected>13.5 million.The toll is constantly rising and the hope of finding more survivors has rapidly faded.The USGS PAGER(United States Geological Survey,Prompt Assessment of Global Earthquake for Response)service estimates economic losses of 10–100 billion US dollars.展开更多
This paper studies the evolution charateristics of positive and negative quakes before Hyugo earthquake of M =7.2 and several strong quakes in Kanto area in Japan.The results show that the earthquakes over a certai...This paper studies the evolution charateristics of positive and negative quakes before Hyugo earthquake of M =7.2 and several strong quakes in Kanto area in Japan.The results show that the earthquakes over a certain megnitude are mainly positive ones a certain time before the main shock in or near the focal regions of most strong quakes,and form a concentratingintervals of positive quakes,The main quakes generally locate in or near the areas of positive quake distribution.Negative quakes often occur several months before the main shocks (not excluding positive ones), with the decrease of LURR (Loading/Unloading Response Ratio) values.It possibly shows that earthquake generating process has come to a short term stage.These characteristics may help to predict the time and location of the future earthquakes,and have been applied to the preliminary prediction of the time and the location of the earthquake of M =6.6 on Sep.11,1996 in Kanto area.展开更多
An 8.1-magnitude earthquake occurred in Nepal April 25 caused severe injuries,causalities and significant property damage.The quake affected 300,000 people of 19 counties in Tibet Autonomous Region to varying degrees ...An 8.1-magnitude earthquake occurred in Nepal April 25 caused severe injuries,causalities and significant property damage.The quake affected 300,000 people of 19 counties in Tibet Autonomous Region to varying degrees and induced debris flows and landslides in many places.CASC subsidiaries China Centre for Resources Satellite Data and Application(CRESDA)and China Satellite Communications Co.,Ltd(China Satcom)activated respectively the emergency response mechanism quickly to provide information and communications support for the disaster rescue operation.展开更多
The presence of heterozygous individuals in a population is crucial for maintaining genetic diversity,which can positively affect fitness and adaptability to environmental changes.While inbreeding generally reduces th...The presence of heterozygous individuals in a population is crucial for maintaining genetic diversity,which can positively affect fitness and adaptability to environmental changes.While inbreeding generally reduces the proportion of heterozygous individuals in a population,polyploidy tends to increase the proportion.North American Populus tremuloides is one of the most widely distributed and ecologically important tree species in the Northern Hemisphere.However,genetic variation in Mexican populations of P.tremuloides,including the genetic signatures of their adaptation to a variety of environments,remains largely uncharacterized.The aim of this study was to analyze how inbreeding coefficient(FIS)and ploidy are associated with clonal richness,population cover,climate and soil traits in 91 marginal to small,isolated populations of this tree species throughout its entire distribution in Mexico.Genetic variables were determined using 36,810 filtered SNPs derived from genome re-sequencing.We found that FIS was approximately between 0 and e1,indicating an extreme heterozygosity excess.One key contributor to the observed extreme heterozygosity excess was asexual reproduction,although ploidy levels cannot explain this excess.Analysis of all neutral SNPs showed that asexual reproduction was positively correlated with observed heterozygosity(Ho)but negatively correlated with expected heterozygosity(He).Analysis of outlier SNPs also showed that asexual reproductionwas positively correlated with Ho and negatively correlated with He,although this latter correlation was not significant.These findings support the presence of a Meselson effect.展开更多
Xi Jinping orders all-out rescue efforts following heavy casualties in 6.8-magnitude Xizang quake President Xi Jinping has ordered all-out rescue efforts to save lives and minimize casualties following a 6.8-magnitude...Xi Jinping orders all-out rescue efforts following heavy casualties in 6.8-magnitude Xizang quake President Xi Jinping has ordered all-out rescue efforts to save lives and minimize casualties following a 6.8-magnitude earthquake that took a heavy toll after jolting Dingri County in the Xizang Autonomous Region on Jan.7.Xi Jinping,also general secretary of the Communist Party of China Central Committee and chairman of the Central Military Commission,ordered utmost efforts to treat the injured.He also urged efforts to prevent secondary disasters,properly resettle affected residents,and handle the aftermath work effectively.It is essential to strengthen earthquake monitoring and early warning,promptly allocate emergency rescue supplies,expedite the repair of damaged infrastructure,ensure the basic needs of residents are met,and guarantee a safe and warm winter for all,Xi Jinping said.展开更多
A 6.1 magnitude earthquake hit Lushan county,Ya'an,Sichuan province in southwest China on Wednesday,June 1 at 5pm.Four people died and 41 were injured in Lushan.The quake was followed by a 4.5-magnitude earthquake...A 6.1 magnitude earthquake hit Lushan county,Ya'an,Sichuan province in southwest China on Wednesday,June 1 at 5pm.Four people died and 41 were injured in Lushan.The quake was followed by a 4.5-magnitude earthquake at 5:03pm in neighboring Baoxing county,also in Ya'an.As of 9am on Thursday,June 2,more than 30 casualties had been reported in Baoxing county.More than 4,500 rescuers were dispatched to the affected areas.展开更多
A 6.1 magnitude earthquake hit Lushan county,Yaran,Sichuan province in southwest China on Wednesday,June 1 at 5pm.Four people died and 41 were injured in Lushan.The quake was followed by a 4.5-magnitude earthquake at ...A 6.1 magnitude earthquake hit Lushan county,Yaran,Sichuan province in southwest China on Wednesday,June 1 at 5pm.Four people died and 41 were injured in Lushan.The quake was followed by a 4.5-magnitude earthquake at 5:03pm in neighboring Baoxing county,also in Ya'an.展开更多
Due to the joint development characteristic and macropore structure of loess,it is easy to cause structure collapse under earthquake or artificial vibration.The study on the loess disaster effect and its mechanism und...Due to the joint development characteristic and macropore structure of loess,it is easy to cause structure collapse under earthquake or artificial vibration.The study on the loess disaster effect and its mechanism under earthquake action is insufficient due to its complexity.Hence,to study the deformation and mechanical properties more accurately,the dynamic characteristics of saturated remolded loess under cyclic dynamic load were tested using a GDS dynamic triaxial instrument in this paper.The test results show that strain and pore water pressure increase gradually at different rates with the development of vibration,and there is an obvious inflection point in the time-history curve of both.When the number of vibrations(N)exceeds this point,the strain increases rapidly,and pore water pressure tends to be stable.Under the action of large amplitude and low-frequency dynamic load,the strain and pore water pressure increase rapidly with fewer vibrations and the deviator stress(q)decreases rapidly,while the sample achieves damage faster with the increase of amplitude.During the application of a dynamic load,the effective stress(p)gradually decreases and its rate of change slows down.Finally,when the saturated remolded loess is subjected to a constant-amplitude dynamic load,the combination of large amplitude and low frequency leads to the failure of the sample in the shortest time.展开更多
1 Türkiye is situated on a part of Earth's crust(地壳)which is like a busy crossroads for tectonic plates(地壳构造板块),where earthquakes happen frequently.Last year,big quakes shook Türkiye and Syria,ca...1 Türkiye is situated on a part of Earth's crust(地壳)which is like a busy crossroads for tectonic plates(地壳构造板块),where earthquakes happen frequently.Last year,big quakes shook Türkiye and Syria,caused by the Anatolian Plate rubbing against the Arabian Plate to the south.展开更多
In order to adopt the best safety procedures, man-made earthquakes should be differentiated as a function of their origin. At least four different types of settings can be recognized in which anthropogenic activities ...In order to adopt the best safety procedures, man-made earthquakes should be differentiated as a function of their origin. At least four different types of settings can be recognized in which anthropogenic activities may generate seismicity:(I) fluid removal from a stratigraphic reservoir in the underground can trigger the compaction of the voids and the collapse of the overlying volume, i.e., graviquakes; the deeper the reservoir, the bigger the volume and the earthquake magnitude;(II) wastewater or gas reinjection provides the reduction of friction in volumes and along fault planes, allowing creep or sudden activation of tectonic discontinuities, i.e., reinjection quakes;(III) fluid injection at supra-lithostatic pressure generates hydrofracturing and micro-seismicity, i.e., hydrofracturing quakes;(IV) fluid extraction or fluid injection,filling or unfilling of artificial lakes modifies the lithostatic load, which is the maximum principal stress in extensional tectonic settings, the minimum principal stress in contractional tectonic settings, and the intermediate principal stress in strike-slip settings, i.e., load quakes; over given pressure values, the increase of the lithostatic load may favour the activation of normal faults, whereas its decrease may favour thrust faults. For example, the filling of an artificial lake may generate normal fault-related seismicity.Therefore, each setting has its peculiarities and the knowledge of the different mechanisms may contribute to the adoption of the appropriate precautions in the various industrial activities.展开更多
The propagation characteristics of the amplitude of the blasting seismic wave under the conditions of various topographies are approached by means of experiments. Some factors affecting the effects of quake insulation...The propagation characteristics of the amplitude of the blasting seismic wave under the conditions of various topographies are approached by means of experiments. Some factors affecting the effects of quake insulation groove, such as the size, the depth and the position of the quake insulation groove, are studied. The amplitudes of the blasting seismic waves under the conditions of the different sizes of the quake insulation groove are measured. According to the experiments, the effects of the quake insulation groove are related to the position, the distance, the energy of the explosion source and the size of the quake insulation groove itself. The farther it is from the explosion source, the smaller the energy is. The lower its position is and the larger its size is, the more remarkable the effects of the quake insulation groove are.展开更多
By earthquake migration (or epicentral migration) is meant that earthquakes occur one after another according to a certain space law. The study of this phenomenon has some significance for the prediction of earthquake...By earthquake migration (or epicentral migration) is meant that earthquakes occur one after another according to a certain space law. The study of this phenomenon has some significance for the prediction of earthquakes. The problem is quite complicated, and moreover, the conditions in different regions are very different. The present note discusses only the earthquake migration in short periods in the province of Kansu (one of the severestseismic regions in China), i.e., the period between the occurrences of two earthquakes is far shorter than the time for the formation of earthquake in Kansu. I. THE THREE EPICENRAL MIGRATORY ZONES IN KANSU (1) The first epicentral migratory zone (extending from the district of Shantan southeastward). In the district of Shantan展开更多
文摘The aim of this investigation is to find possible changes in ultra-deep earthquakes (UDQ) during different seasons of the year. In the acquisition of data for our previous work we observed an inexplicable pattern of growth of ultra-deep tremors (UDQ) during the studied period. Apparently, there is no viable explanation for growth occurring at such a level, presumably in the asthenosphere. Current research and theories developed for the inner layers of the Earth do not explain such variations. Therefore, a possible explanation would be in external factors such as the seasons of the year, which are determined by changes in the Earth’s axial tilt, and therefore the portion of the earth that is angled toward the sun. This paper focuses exclusively on UDQ events. To simplify the calculations, we consider four main locations;this includes one more region than our previous paper but includes only UDQ data. The results showed that during spring and autumn UDQ events grew slightly in both Northern and Southern Hemispheres. It is also suggested that a contributor to UDQ events is friction from the subducting lithosphere against the continental plates.
文摘In early February,2023,southeastern Türkiye and northern Syria were hit by a series of deadly earthquakes(two of them above magnitude 7.5)that are proving to be one of the most significant earthquake disasters of this century.These“twin quakes”caused a large number of casualties and property losses.As of press time,the death toll in Türkiye and Syria has surpassed 51000 and the number of injured has surpassed 120000,with the number affected>13.5 million.The toll is constantly rising and the hope of finding more survivors has rapidly faded.The USGS PAGER(United States Geological Survey,Prompt Assessment of Global Earthquake for Response)service estimates economic losses of 10–100 billion US dollars.
文摘This paper studies the evolution charateristics of positive and negative quakes before Hyugo earthquake of M =7.2 and several strong quakes in Kanto area in Japan.The results show that the earthquakes over a certain megnitude are mainly positive ones a certain time before the main shock in or near the focal regions of most strong quakes,and form a concentratingintervals of positive quakes,The main quakes generally locate in or near the areas of positive quake distribution.Negative quakes often occur several months before the main shocks (not excluding positive ones), with the decrease of LURR (Loading/Unloading Response Ratio) values.It possibly shows that earthquake generating process has come to a short term stage.These characteristics may help to predict the time and location of the future earthquakes,and have been applied to the preliminary prediction of the time and the location of the earthquake of M =6.6 on Sep.11,1996 in Kanto area.
文摘An 8.1-magnitude earthquake occurred in Nepal April 25 caused severe injuries,causalities and significant property damage.The quake affected 300,000 people of 19 counties in Tibet Autonomous Region to varying degrees and induced debris flows and landslides in many places.CASC subsidiaries China Centre for Resources Satellite Data and Application(CRESDA)and China Satellite Communications Co.,Ltd(China Satcom)activated respectively the emergency response mechanism quickly to provide information and communications support for the disaster rescue operation.
基金We thank the Mexican Consejo Nacional de Humanidades,Ciencias y Tecnologías(CONAHCYT)for the financial support provided to the first author to carry out his training in the Institutional Doctoral Program in Agricultural and Forestry Sciences(PIDCAFUJED)with Scholarship No.334852financial support with agreement number CONACYT-FRQ-2016:279459 for the project“Genome-wide scans for detecting adaptation to climate and soil in Populus tremuloides as the most widely distributed tree species in North America”Dr.Jesús M.Olivas-García assisted in the sampling in the state of Chihuahua,Mexico,and Katrin Groppe,Thünen Institute of Forest Genetics,Germany,provided excellent lab work.The Emerging Leaders of the Americas Program(ELAP)of the Government of Canada awarded a scholarship and the Institute of Integrative and Systems Biology(IBIS)of Laval University allowed the use of its campus and contributed to the training of the first author.
文摘The presence of heterozygous individuals in a population is crucial for maintaining genetic diversity,which can positively affect fitness and adaptability to environmental changes.While inbreeding generally reduces the proportion of heterozygous individuals in a population,polyploidy tends to increase the proportion.North American Populus tremuloides is one of the most widely distributed and ecologically important tree species in the Northern Hemisphere.However,genetic variation in Mexican populations of P.tremuloides,including the genetic signatures of their adaptation to a variety of environments,remains largely uncharacterized.The aim of this study was to analyze how inbreeding coefficient(FIS)and ploidy are associated with clonal richness,population cover,climate and soil traits in 91 marginal to small,isolated populations of this tree species throughout its entire distribution in Mexico.Genetic variables were determined using 36,810 filtered SNPs derived from genome re-sequencing.We found that FIS was approximately between 0 and e1,indicating an extreme heterozygosity excess.One key contributor to the observed extreme heterozygosity excess was asexual reproduction,although ploidy levels cannot explain this excess.Analysis of all neutral SNPs showed that asexual reproduction was positively correlated with observed heterozygosity(Ho)but negatively correlated with expected heterozygosity(He).Analysis of outlier SNPs also showed that asexual reproductionwas positively correlated with Ho and negatively correlated with He,although this latter correlation was not significant.These findings support the presence of a Meselson effect.
文摘Xi Jinping orders all-out rescue efforts following heavy casualties in 6.8-magnitude Xizang quake President Xi Jinping has ordered all-out rescue efforts to save lives and minimize casualties following a 6.8-magnitude earthquake that took a heavy toll after jolting Dingri County in the Xizang Autonomous Region on Jan.7.Xi Jinping,also general secretary of the Communist Party of China Central Committee and chairman of the Central Military Commission,ordered utmost efforts to treat the injured.He also urged efforts to prevent secondary disasters,properly resettle affected residents,and handle the aftermath work effectively.It is essential to strengthen earthquake monitoring and early warning,promptly allocate emergency rescue supplies,expedite the repair of damaged infrastructure,ensure the basic needs of residents are met,and guarantee a safe and warm winter for all,Xi Jinping said.
文摘A 6.1 magnitude earthquake hit Lushan county,Ya'an,Sichuan province in southwest China on Wednesday,June 1 at 5pm.Four people died and 41 were injured in Lushan.The quake was followed by a 4.5-magnitude earthquake at 5:03pm in neighboring Baoxing county,also in Ya'an.As of 9am on Thursday,June 2,more than 30 casualties had been reported in Baoxing county.More than 4,500 rescuers were dispatched to the affected areas.
文摘A 6.1 magnitude earthquake hit Lushan county,Yaran,Sichuan province in southwest China on Wednesday,June 1 at 5pm.Four people died and 41 were injured in Lushan.The quake was followed by a 4.5-magnitude earthquake at 5:03pm in neighboring Baoxing county,also in Ya'an.
基金financially supported by the National Natural Science Foundation of China(No.42090053,No.41922054).
文摘Due to the joint development characteristic and macropore structure of loess,it is easy to cause structure collapse under earthquake or artificial vibration.The study on the loess disaster effect and its mechanism under earthquake action is insufficient due to its complexity.Hence,to study the deformation and mechanical properties more accurately,the dynamic characteristics of saturated remolded loess under cyclic dynamic load were tested using a GDS dynamic triaxial instrument in this paper.The test results show that strain and pore water pressure increase gradually at different rates with the development of vibration,and there is an obvious inflection point in the time-history curve of both.When the number of vibrations(N)exceeds this point,the strain increases rapidly,and pore water pressure tends to be stable.Under the action of large amplitude and low-frequency dynamic load,the strain and pore water pressure increase rapidly with fewer vibrations and the deviator stress(q)decreases rapidly,while the sample achieves damage faster with the increase of amplitude.During the application of a dynamic load,the effective stress(p)gradually decreases and its rate of change slows down.Finally,when the saturated remolded loess is subjected to a constant-amplitude dynamic load,the combination of large amplitude and low frequency leads to the failure of the sample in the shortest time.
文摘1 Türkiye is situated on a part of Earth's crust(地壳)which is like a busy crossroads for tectonic plates(地壳构造板块),where earthquakes happen frequently.Last year,big quakes shook Türkiye and Syria,caused by the Anatolian Plate rubbing against the Arabian Plate to the south.
文摘In order to adopt the best safety procedures, man-made earthquakes should be differentiated as a function of their origin. At least four different types of settings can be recognized in which anthropogenic activities may generate seismicity:(I) fluid removal from a stratigraphic reservoir in the underground can trigger the compaction of the voids and the collapse of the overlying volume, i.e., graviquakes; the deeper the reservoir, the bigger the volume and the earthquake magnitude;(II) wastewater or gas reinjection provides the reduction of friction in volumes and along fault planes, allowing creep or sudden activation of tectonic discontinuities, i.e., reinjection quakes;(III) fluid injection at supra-lithostatic pressure generates hydrofracturing and micro-seismicity, i.e., hydrofracturing quakes;(IV) fluid extraction or fluid injection,filling or unfilling of artificial lakes modifies the lithostatic load, which is the maximum principal stress in extensional tectonic settings, the minimum principal stress in contractional tectonic settings, and the intermediate principal stress in strike-slip settings, i.e., load quakes; over given pressure values, the increase of the lithostatic load may favour the activation of normal faults, whereas its decrease may favour thrust faults. For example, the filling of an artificial lake may generate normal fault-related seismicity.Therefore, each setting has its peculiarities and the knowledge of the different mechanisms may contribute to the adoption of the appropriate precautions in the various industrial activities.
文摘The propagation characteristics of the amplitude of the blasting seismic wave under the conditions of various topographies are approached by means of experiments. Some factors affecting the effects of quake insulation groove, such as the size, the depth and the position of the quake insulation groove, are studied. The amplitudes of the blasting seismic waves under the conditions of the different sizes of the quake insulation groove are measured. According to the experiments, the effects of the quake insulation groove are related to the position, the distance, the energy of the explosion source and the size of the quake insulation groove itself. The farther it is from the explosion source, the smaller the energy is. The lower its position is and the larger its size is, the more remarkable the effects of the quake insulation groove are.
文摘By earthquake migration (or epicentral migration) is meant that earthquakes occur one after another according to a certain space law. The study of this phenomenon has some significance for the prediction of earthquakes. The problem is quite complicated, and moreover, the conditions in different regions are very different. The present note discusses only the earthquake migration in short periods in the province of Kansu (one of the severestseismic regions in China), i.e., the period between the occurrences of two earthquakes is far shorter than the time for the formation of earthquake in Kansu. I. THE THREE EPICENRAL MIGRATORY ZONES IN KANSU (1) The first epicentral migratory zone (extending from the district of Shantan southeastward). In the district of Shantan
