Three M_(W)>7.0 earthquakes in 2020-2021 occurred in the Shumagin seismic gap and its adjacent area of the Alaska-Aleutian subduction zone,including the Mw7.8 Simeonof thrust earthquake on July 22,2020,the M_(W)7.6...Three M_(W)>7.0 earthquakes in 2020-2021 occurred in the Shumagin seismic gap and its adjacent area of the Alaska-Aleutian subduction zone,including the Mw7.8 Simeonof thrust earthquake on July 22,2020,the M_(W)7.6 Sand Point strike-slip earthquake on October 19,2020,and the M_(W)8.2 Chignik thrust earthquake on July 29,2021.The spatial and temporal proximity of these three earthquakes prompts us to probe stress-triggering effects among them.Here we examine the coseismic Coulomb stress change imparted by the three earthquakes and their influence on the subduction interface.Our results show that:(1)The Simeonof earthquake has strong loading effects on the subsequent Sand Point and Chignik earthquakes,with the Coulomb stress changes of 3.95 bars and 2.89 bars,respectively.The Coulomb stress change caused by the Sand Point earthquake at the hypocenter of the Chignik earthquake is merely around 0.01 bars,suggesting the negligible triggering effect on the latter earthquake;(2)The triggering effects of the Simeonof,Sand Point,and Chignik earthquakes on aftershocks within three months are not well pronounced because of the triggering rates of 38%,14%,and 43%respectively.Other factors may have played an important role in promoting the occurrence of these aftershocks,such as the roughness of the subduction interface,the complicated velocity structure of the lithosphere,and the heterogeneous prestress therein;(3)The three earthquakes caused remarkable coseismic Coulomb stress changes at the subduction interface nearby these mainshocks,with an average Coulomb stress change of 3.2 bars in the shallow region directly inwards the trench.展开更多
近年来,随着知识更新速度的加快和教育国际化的不断深入,各国纷纷大力发展终身教育、倡导终身学习,以不断提高国家的教育竞争力。联合国教科文组织终身学习研究所(UNESCO Institute for Lifelong Learning,UIL)是国际成人教育和终身教...近年来,随着知识更新速度的加快和教育国际化的不断深入,各国纷纷大力发展终身教育、倡导终身学习,以不断提高国家的教育竞争力。联合国教科文组织终身学习研究所(UNESCO Institute for Lifelong Learning,UIL)是国际成人教育和终身教育研究、交流的枢纽,其战略规划可为我国发展终身教育提供重要参考。文章翻译、摘编自UIL的中期规划报告。该战略报告根据联合国教科文组织在教育方面的三项重要目标,从世界教育发展的宏观趋势入手,提出UIL在2014-2021年间的三大战略,即帮助成员发展终身学习能力,提高UIL自身的研究能力,重组宣传方式并拓展组织形态。UIL还将密切与国际组织、公民社会的合作,继续落实终身学习政策和战略项目、文化普及和基本技能项目、成人学习和教育项目,以协助成员制定终身学习政策、普及终身学习观念、提高成人识字率。展开更多
基金supported by grants from the National Natural Science Foundation of China(Grant No.sU2139205,41774011,41874011)the National Key Research and Development Program of China(Grant No.2018YFC1503605)。
文摘Three M_(W)>7.0 earthquakes in 2020-2021 occurred in the Shumagin seismic gap and its adjacent area of the Alaska-Aleutian subduction zone,including the Mw7.8 Simeonof thrust earthquake on July 22,2020,the M_(W)7.6 Sand Point strike-slip earthquake on October 19,2020,and the M_(W)8.2 Chignik thrust earthquake on July 29,2021.The spatial and temporal proximity of these three earthquakes prompts us to probe stress-triggering effects among them.Here we examine the coseismic Coulomb stress change imparted by the three earthquakes and their influence on the subduction interface.Our results show that:(1)The Simeonof earthquake has strong loading effects on the subsequent Sand Point and Chignik earthquakes,with the Coulomb stress changes of 3.95 bars and 2.89 bars,respectively.The Coulomb stress change caused by the Sand Point earthquake at the hypocenter of the Chignik earthquake is merely around 0.01 bars,suggesting the negligible triggering effect on the latter earthquake;(2)The triggering effects of the Simeonof,Sand Point,and Chignik earthquakes on aftershocks within three months are not well pronounced because of the triggering rates of 38%,14%,and 43%respectively.Other factors may have played an important role in promoting the occurrence of these aftershocks,such as the roughness of the subduction interface,the complicated velocity structure of the lithosphere,and the heterogeneous prestress therein;(3)The three earthquakes caused remarkable coseismic Coulomb stress changes at the subduction interface nearby these mainshocks,with an average Coulomb stress change of 3.2 bars in the shallow region directly inwards the trench.
文摘近年来,随着知识更新速度的加快和教育国际化的不断深入,各国纷纷大力发展终身教育、倡导终身学习,以不断提高国家的教育竞争力。联合国教科文组织终身学习研究所(UNESCO Institute for Lifelong Learning,UIL)是国际成人教育和终身教育研究、交流的枢纽,其战略规划可为我国发展终身教育提供重要参考。文章翻译、摘编自UIL的中期规划报告。该战略报告根据联合国教科文组织在教育方面的三项重要目标,从世界教育发展的宏观趋势入手,提出UIL在2014-2021年间的三大战略,即帮助成员发展终身学习能力,提高UIL自身的研究能力,重组宣传方式并拓展组织形态。UIL还将密切与国际组织、公民社会的合作,继续落实终身学习政策和战略项目、文化普及和基本技能项目、成人学习和教育项目,以协助成员制定终身学习政策、普及终身学习观念、提高成人识字率。
