The increase in frequency and intensity of Extreme High-temperature Events(EHEs)over Central-Eastern China(CEC)in recent decades has severely impacted social development and livelihoods.Using observation and reanalysi...The increase in frequency and intensity of Extreme High-temperature Events(EHEs)over Central-Eastern China(CEC)in recent decades has severely impacted social development and livelihoods.Using observation and reanalysis datasets,this study explores the effect of the East Asian subtropical westerly jet stream(EAJ)on the CEC EHEs for the summers spanning 1979–2020.Considering its general relative location to the right side of the upper-level jet stream exit region,CEC would theoretically suffer more EHEs with a stronger and northwardly-shifted EAJ in summer due to the likelihood of abnormal subsidence induced by the EAJ.However,such an EAJ–EHE connection has been unstable over the past four decades but has displayed an evident interdecadal change.Before the late 1990s,the interannual variation of the EAJ was manifested mainly by its meridional displacement in the northeastern part of East Asia;thus,the atmospheric responses were essentially located to the east of CEC,exerting less of an influence on the CEC EHEs.However,since the late 1990s,the EAJ variation has featured an intensity change in its center over the northwest portion of the CEC,which has resulted in a westward shift in atmospheric responses to cover the CEC region.Therefore,the EAJ could potentially affect the summer CEC EHEs during 2000–21.Our findings offer support for an in-depth understanding of the formation mechanisms of extreme weather/climate events of this nature and thus provide a scientific reference for seasonal climate predictions.展开更多
The 3-D velocity tomography image of the central-eastern part of Qilianshan is obtained by the joint inversion of 3-D velocity structure and focal parameters based on the S-P data of micro-earthquakes recorded by the ...The 3-D velocity tomography image of the central-eastern part of Qilianshan is obtained by the joint inversion of 3-D velocity structure and focal parameters based on the S-P data of micro-earthquakes recorded by the digital seismic network set up for a Sino-French cooperation program since 1996. The inversed velocity structure does primarily reflect some important features of the deep structure in the region and provide the scientific background for the further study of active tectonic structure and the calculation of earthquake parameters.展开更多
The 3-D velocity tomography image of the central-eastern part of Qilianshan is obtained by the joint inversion of 3-D velocity structure and focal parameters based on the S-P data of micro-earthquakes recorded by the ...The 3-D velocity tomography image of the central-eastern part of Qilianshan is obtained by the joint inversion of 3-D velocity structure and focal parameters based on the S-P data of micro-earthquakes recorded by the digital seismic network set up for a Sino-French cooperation program since 1996. The inversed velocity structure does primarily reflect some important features of the deep structure in the region and provide the scientific background for the further study of active tectonic structure and the calculation of earthquake parameters.展开更多
The results inferred from experiments with analogue models carried out previously have shown that two types of plastic-flow waves, “fast-waves" and “slow-waves", are induced in the lower lithosphere (inclu...The results inferred from experiments with analogue models carried out previously have shown that two types of plastic-flow waves, “fast-waves" and “slow-waves", are induced in the lower lithosphere (including the lower crust and lithospheric mantle) under driving at plate boundaries and both of them are viscous gravity waves formed by the superposition of major and subsidiary waves. The major waves are similar to solitary waves and the subsidiary waves are traveling waves. The plastic-flow waves in the lower lithosphere control seismic activities in the overlying seismogenic layer and result in the distribution of earthquakes along the wave-crest belts. “Fast-waves" propagated with velocities of orders of magnitude of 100～102km/a have been verified by wave-controlled earthquake migration, showing the “decade waves" and “century waves" with the average periods of 10.8 and 93.4 a, respectively, which originate from the Himalayan driving boundary. According to the recognition of the patterns of the belt-like distribution of strong earthquakes with M S≥7.0, it is indicated further in this paper that the “slow-waves" with velocities of orders of magnitude of 100～101 m/a also originated under compression from the Himalayan driving boundary. Strong earthquakes with M S≥7.0 are controlled mainly by subsidiary waves, because the major waves with a duration of up to 106 a for each disturbance cannot result in the accumulation of enough energy for strong earthquakes due to the relaxation of the upper crust. The subsidiary waves propagate with an average wave length of 445 km, velocities of 0.81～2.80 m/a and periods of 0.16～0.55 Ma. The wave-generating time at the Himalayan driving boundary is about 1.34～4.59 Ma before present for the “slow-waves", corresponding to the stage from the Mid Pliocene to the Mid Early-Pleistocene and being identical with one of the major tectonic episodes of the Himalayan tectonic movement. It is shown from the recognition of the wave-controlled belts of strong earthquakes that two optimal patterns of wave-crest belts originated simultaneously from the eastern and western segments of the Himalayan arc, respectively. The overlap of wave-crest belts of these two systems is responsible for the relative concentration of energy and forms the seismic-energy-background zones for strong earthquakes with M S≥7.0.展开更多
According to the ＂Netlike Plastic-Flow （NPF）＂ continental dynamics model, the transition of the deformation regime from brittle in shallow layers to ductile in deep layers in the lithosphere, and the controlling e...According to the ＂Netlike Plastic-Flow （NPF）＂ continental dynamics model, the transition of the deformation regime from brittle in shallow layers to ductile in deep layers in the lithosphere, and the controlling effect of NPF in the lower lithosphere result in intraplate multilayer tectonic deformation. NPF is a viscous （plastic） flow accompanied by shear strain localization, forming a plastic-flow network in the lower lithosphere. The strain rates in the seismogeulc layer can be estimated using the ＂earthquake-recurrence-interval＂ method, in which the strain rate is calculated in terms of the recurrence interval of two sequential earthquakes and the seismic probability of the second earthquake. The strains in the lower lithosphere are estimated using the ＂conjugate-angle＂ method, which takes the relationship between the conjugate angles and the compressive strains of the network, and calculates the characteristic strain rates in this layer from the strains and the durations of deformation inferred. The contour map of characteristic maximum principal compressive strain rates in the lower lithosphere in central-eastern Asia given in the paper shows strain rates with magnitudes on the order of 10^-15 - 10^-14/s in this region. The strain rates within the plastic-flow belts, which control seismic activities in the seismogeulc layer, are greater than the characteristic strain rates of the network and, in addition, the strain rates and seismic activities in the seismogeulc layer are also influenced by other factors, including the directive action of driving boundary along the upper crust, the effects of plastic-flow waves and the existence of the transitional weak layer distributed discontinuously between the upper and lower layers. The comparison between the strain rates in the seismogeulc layer and the characteristic strain rates in the lower lithosphere for 11 potential hypocenter areas in the region from the Qinghai-Xizang （Tibet） plateau to the North China plain indicates that, except for the considerable deviation in the Linfen basin, Shanxi Province, the linear correlation between the strain rates in the upper and lower layers is obvious for all other 10 areas with a slope β= 1.75 ±0.5 （i.e. the ratio of strain rate in the upper layer to that in the lower one）. It is suggested that the contour map of characteristic strain rates together with the ratio β can be used to approximate the strain rates of potential hypocenters in medium- and long-term earthquake predictions, and the effects of driving boundaries and relative stable blocks on the hypocenter areas should be considered as sufficiently as possible for taking the β values properly.展开更多
The study of the netlike earthquake distribution indicates that in the central-eastern part of Asia continent there are two network systems: the central-eastern Asia system and the southeastern China system.As interpr...The study of the netlike earthquake distribution indicates that in the central-eastern part of Asia continent there are two network systems: the central-eastern Asia system and the southeastern China system.As interpreted by the multilayer tectonic model,they might be a manifestation of the plastic-flow network systems in the lower lithosphere,including the lower crust and the mantle lid.Each network system is enclosed by different types of boundaries,including one driving boundary and some constraining and releasing boundaries.The two plastic-flow network systems with the Himalayan and Taiwan arcs as their driving boundaries play the role of controlling the intraplate tectonic deformation,stress field,seismicity,and subdivision of tectonic units.展开更多
地球区别于其它类地行星的重要特征在于其独特的长英质大陆地壳组成。作为全球规模最大的增生型造山带,中亚造山带为揭示大陆地壳的生长演化过程和机制提供了关键研究场所。该造山带东段广泛发育的多期次花岗质岩体,因其显著高的正εNd...地球区别于其它类地行星的重要特征在于其独特的长英质大陆地壳组成。作为全球规模最大的增生型造山带,中亚造山带为揭示大陆地壳的生长演化过程和机制提供了关键研究场所。该造山带东段广泛发育的多期次花岗质岩体,因其显著高的正εNd(t)值和低的初始^(87)Sr/^(86)Sr(ISr)值特征,被视为显生宙地壳生长的重要证据(Jahn et al.,2000;Wu Fuyuan et al.,2000)。展开更多
目的探讨在人群水平上不同暴露对心血管疾病的“贡献”,构建风险预测模型,对于有效分配预防资源有重要意义。方法采用CHNS(China Health and Nutrition Survey,中国健康与营养调查)数据库2009、2011及2015年中东部地区10个省市(北京、...目的探讨在人群水平上不同暴露对心血管疾病的“贡献”,构建风险预测模型,对于有效分配预防资源有重要意义。方法采用CHNS(China Health and Nutrition Survey,中国健康与营养调查)数据库2009、2011及2015年中东部地区10个省市(北京、辽宁、黑龙江、上海、山东、河南、湖北、湖南、广西及江苏)35~75岁9899例常住居民作为研究对象。单因素分析纳入变量(性别、年龄、BMI、婚姻状况、城乡、睡眠时间、吸烟、饮酒、糖尿病、教育程度及医保),在logistic回归分析危险因素基础上,估计某(些)危险因素的多因素调整人群归因危险度,随机抽取70%(n=6927)为建模组,30%(n=2974)为验证组,构建CVD风险预测模型,同时利用受试者特征工作曲线(Receiver operating characteristic curve,ROC)及Hosmer-Lemeshow拟合优度检验(Good of fit test)评估风险预测模型区分度和校准度。结果BMI、睡眠时间、吸烟、饮酒以及糖尿病的调整人群归因危险度与95%置信区间分别为32.20%(27.67%~36.89%)、7.90%(1.68%~16.58%)、18.56%(11.35%~26.24%)、6.47%(0.11%~13.25%)、5.73%(4.42%~7.03%)。多因素调整人群归因危险度百分比结果表明,BMI在心血管疾病患病病因中占主导地位,吸烟影响次之,睡眠时间、饮酒及糖尿病影响较弱。低风险患病率为18.44%,较高风险的患病率为14.19%,高风险患病率为42.52%。ROC曲线下面积AUC=0.711,P<0.001;Hosmer-Lemeshow拟合优度P=0.257。结论未来应重点关注高风险人群,控制体质指数到正常范围,减少吸烟,对预防心血管疾病有重大意义。风险预测模型具有较好的区分性和实用性等价值,可为预防心血管疾病提供一定的预测能力。展开更多
基金supported by the Natural Science Foundation of China(Grant No:42105025,42075189,42275036,and 42430610)the National Key R&D Program of China under Grant 2021YFA0718000+3 种基金the China Meteorological Administration Youth Innovation Team(CMA2023QN15)China Meteorological Administration Key Innovation Team(CMA2024ZD07)the development fund of South China Sea Institute of Oceanology of the Chinese Academy of Sciences(SCSIO202203 and SCSIO202208)the Open Research Fund of the State Key Laboratory of Tropical Oceanography(South China Sea Institute of Oceanology,Chinese Academy of Sciences)(LTO2110)。
文摘The increase in frequency and intensity of Extreme High-temperature Events(EHEs)over Central-Eastern China(CEC)in recent decades has severely impacted social development and livelihoods.Using observation and reanalysis datasets,this study explores the effect of the East Asian subtropical westerly jet stream(EAJ)on the CEC EHEs for the summers spanning 1979–2020.Considering its general relative location to the right side of the upper-level jet stream exit region,CEC would theoretically suffer more EHEs with a stronger and northwardly-shifted EAJ in summer due to the likelihood of abnormal subsidence induced by the EAJ.However,such an EAJ–EHE connection has been unstable over the past four decades but has displayed an evident interdecadal change.Before the late 1990s,the interannual variation of the EAJ was manifested mainly by its meridional displacement in the northeastern part of East Asia;thus,the atmospheric responses were essentially located to the east of CEC,exerting less of an influence on the CEC EHEs.However,since the late 1990s,the EAJ variation has featured an intensity change in its center over the northwest portion of the CEC,which has resulted in a westward shift in atmospheric responses to cover the CEC region.Therefore,the EAJ could potentially affect the summer CEC EHEs during 2000–21.Our findings offer support for an in-depth understanding of the formation mechanisms of extreme weather/climate events of this nature and thus provide a scientific reference for seasonal climate predictions.
基金National Natural Science Foundation of China (40074010) and Natural Science Foundation of Gansu Province (ZS981-A25-011)
文摘The 3-D velocity tomography image of the central-eastern part of Qilianshan is obtained by the joint inversion of 3-D velocity structure and focal parameters based on the S-P data of micro-earthquakes recorded by the digital seismic network set up for a Sino-French cooperation program since 1996. The inversed velocity structure does primarily reflect some important features of the deep structure in the region and provide the scientific background for the further study of active tectonic structure and the calculation of earthquake parameters.
基金National Natural Science Foundation of China (40074010) and Natural Science Foundation of Gansu Province(ZS981-A25-011).
文摘The 3-D velocity tomography image of the central-eastern part of Qilianshan is obtained by the joint inversion of 3-D velocity structure and focal parameters based on the S-P data of micro-earthquakes recorded by the digital seismic network set up for a Sino-French cooperation program since 1996. The inversed velocity structure does primarily reflect some important features of the deep structure in the region and provide the scientific background for the further study of active tectonic structure and the calculation of earthquake parameters.
文摘The results inferred from experiments with analogue models carried out previously have shown that two types of plastic-flow waves, “fast-waves" and “slow-waves", are induced in the lower lithosphere (including the lower crust and lithospheric mantle) under driving at plate boundaries and both of them are viscous gravity waves formed by the superposition of major and subsidiary waves. The major waves are similar to solitary waves and the subsidiary waves are traveling waves. The plastic-flow waves in the lower lithosphere control seismic activities in the overlying seismogenic layer and result in the distribution of earthquakes along the wave-crest belts. “Fast-waves" propagated with velocities of orders of magnitude of 100～102km/a have been verified by wave-controlled earthquake migration, showing the “decade waves" and “century waves" with the average periods of 10.8 and 93.4 a, respectively, which originate from the Himalayan driving boundary. According to the recognition of the patterns of the belt-like distribution of strong earthquakes with M S≥7.0, it is indicated further in this paper that the “slow-waves" with velocities of orders of magnitude of 100～101 m/a also originated under compression from the Himalayan driving boundary. Strong earthquakes with M S≥7.0 are controlled mainly by subsidiary waves, because the major waves with a duration of up to 106 a for each disturbance cannot result in the accumulation of enough energy for strong earthquakes due to the relaxation of the upper crust. The subsidiary waves propagate with an average wave length of 445 km, velocities of 0.81～2.80 m/a and periods of 0.16～0.55 Ma. The wave-generating time at the Himalayan driving boundary is about 1.34～4.59 Ma before present for the “slow-waves", corresponding to the stage from the Mid Pliocene to the Mid Early-Pleistocene and being identical with one of the major tectonic episodes of the Himalayan tectonic movement. It is shown from the recognition of the wave-controlled belts of strong earthquakes that two optimal patterns of wave-crest belts originated simultaneously from the eastern and western segments of the Himalayan arc, respectively. The overlap of wave-crest belts of these two systems is responsible for the relative concentration of energy and forms the seismic-energy-background zones for strong earthquakes with M S≥7.0.
基金Supported bythe Joint Earthquake Science Foundation of China(grant 199061) Contribution No.2005B0011 of the Institute of Geology,China Earthquake Administration.
文摘According to the ＂Netlike Plastic-Flow （NPF）＂ continental dynamics model, the transition of the deformation regime from brittle in shallow layers to ductile in deep layers in the lithosphere, and the controlling effect of NPF in the lower lithosphere result in intraplate multilayer tectonic deformation. NPF is a viscous （plastic） flow accompanied by shear strain localization, forming a plastic-flow network in the lower lithosphere. The strain rates in the seismogeulc layer can be estimated using the ＂earthquake-recurrence-interval＂ method, in which the strain rate is calculated in terms of the recurrence interval of two sequential earthquakes and the seismic probability of the second earthquake. The strains in the lower lithosphere are estimated using the ＂conjugate-angle＂ method, which takes the relationship between the conjugate angles and the compressive strains of the network, and calculates the characteristic strain rates in this layer from the strains and the durations of deformation inferred. The contour map of characteristic maximum principal compressive strain rates in the lower lithosphere in central-eastern Asia given in the paper shows strain rates with magnitudes on the order of 10^-15 - 10^-14/s in this region. The strain rates within the plastic-flow belts, which control seismic activities in the seismogeulc layer, are greater than the characteristic strain rates of the network and, in addition, the strain rates and seismic activities in the seismogeulc layer are also influenced by other factors, including the directive action of driving boundary along the upper crust, the effects of plastic-flow waves and the existence of the transitional weak layer distributed discontinuously between the upper and lower layers. The comparison between the strain rates in the seismogeulc layer and the characteristic strain rates in the lower lithosphere for 11 potential hypocenter areas in the region from the Qinghai-Xizang （Tibet） plateau to the North China plain indicates that, except for the considerable deviation in the Linfen basin, Shanxi Province, the linear correlation between the strain rates in the upper and lower layers is obvious for all other 10 areas with a slope β= 1.75 ±0.5 （i.e. the ratio of strain rate in the upper layer to that in the lower one）. It is suggested that the contour map of characteristic strain rates together with the ratio β can be used to approximate the strain rates of potential hypocenters in medium- and long-term earthquake predictions, and the effects of driving boundaries and relative stable blocks on the hypocenter areas should be considered as sufficiently as possible for taking the β values properly.
基金This Project was sponsored by the National Natural Science Foundation of China under No.49070196.
文摘The study of the netlike earthquake distribution indicates that in the central-eastern part of Asia continent there are two network systems: the central-eastern Asia system and the southeastern China system.As interpreted by the multilayer tectonic model,they might be a manifestation of the plastic-flow network systems in the lower lithosphere,including the lower crust and the mantle lid.Each network system is enclosed by different types of boundaries,including one driving boundary and some constraining and releasing boundaries.The two plastic-flow network systems with the Himalayan and Taiwan arcs as their driving boundaries play the role of controlling the intraplate tectonic deformation,stress field,seismicity,and subdivision of tectonic units.
文摘地球区别于其它类地行星的重要特征在于其独特的长英质大陆地壳组成。作为全球规模最大的增生型造山带,中亚造山带为揭示大陆地壳的生长演化过程和机制提供了关键研究场所。该造山带东段广泛发育的多期次花岗质岩体,因其显著高的正εNd(t)值和低的初始^(87)Sr/^(86)Sr(ISr)值特征,被视为显生宙地壳生长的重要证据(Jahn et al.,2000;Wu Fuyuan et al.,2000)。
文摘目的探讨在人群水平上不同暴露对心血管疾病的“贡献”,构建风险预测模型,对于有效分配预防资源有重要意义。方法采用CHNS(China Health and Nutrition Survey,中国健康与营养调查)数据库2009、2011及2015年中东部地区10个省市(北京、辽宁、黑龙江、上海、山东、河南、湖北、湖南、广西及江苏)35~75岁9899例常住居民作为研究对象。单因素分析纳入变量(性别、年龄、BMI、婚姻状况、城乡、睡眠时间、吸烟、饮酒、糖尿病、教育程度及医保),在logistic回归分析危险因素基础上,估计某(些)危险因素的多因素调整人群归因危险度,随机抽取70%(n=6927)为建模组,30%(n=2974)为验证组,构建CVD风险预测模型,同时利用受试者特征工作曲线(Receiver operating characteristic curve,ROC)及Hosmer-Lemeshow拟合优度检验(Good of fit test)评估风险预测模型区分度和校准度。结果BMI、睡眠时间、吸烟、饮酒以及糖尿病的调整人群归因危险度与95%置信区间分别为32.20%(27.67%~36.89%)、7.90%(1.68%~16.58%)、18.56%(11.35%~26.24%)、6.47%(0.11%~13.25%)、5.73%(4.42%~7.03%)。多因素调整人群归因危险度百分比结果表明,BMI在心血管疾病患病病因中占主导地位,吸烟影响次之,睡眠时间、饮酒及糖尿病影响较弱。低风险患病率为18.44%,较高风险的患病率为14.19%,高风险患病率为42.52%。ROC曲线下面积AUC=0.711,P<0.001;Hosmer-Lemeshow拟合优度P=0.257。结论未来应重点关注高风险人群,控制体质指数到正常范围,减少吸烟,对预防心血管疾病有重大意义。风险预测模型具有较好的区分性和实用性等价值,可为预防心血管疾病提供一定的预测能力。
