【摘要】 通过对智利地震前全球不同时空范围地震活动特征分析,发现:①智利地震前出现了两类地震空区:第一类空区为1900年以来形成的360km长的MW≥8.0地震空段,第二类空区为震前5年形成的780km长的M≥5.5地震空段;②1986—2010年,智利中南部仅发生1次MW7.1地震,表现为显著的MW≥7.0地震平静异常;③2007—2009年,南美板块M≥6.5地震显著平静,平静打破后3个月发生了智利MW8.8地震;④1993年以来,南美板块中、深源地震活动显著增强;⑤智利地震的发生是2004年开始的全球MW≥8.5地震活跃时段的继续发展,根据前2个活跃时段的特点,认为今后数年全球还将发生数次MW≥8.5地震,且环太平洋地震带是MW≥8.0地震的主体活动地区.更多还原

【Abstract】 Spatio-temporal variation of seismic activity before the great Chile earthquake on February 27,2010,is studied.Some results are as follows:① Two types of seismic gaps appeared before the Chile MW8.8 shock.One is the background gap of MW≥8.0 earthquakes with 360 km long since 1900.The other is the seismogenic gap of M≥5.5 earthquakes with 780 km long 5 years before the Chile earthquake.② There was only one earthquake with MW7.1 in middle and southern part of Chile from 1986 to 2010.This is the long-term background anomaly of the obvious quiescence of MW≥7.0 earthquakes before the Chile earthquake.③ The quiescence of earthquakes with M≥6.5 appeared in South American Plate and its vicinity during 2007—2009,and the quietude state has been disappeared three months before the MW8.8 shock.④ The deep and intermediate-depth earthquake activity has been noticeably strengthened in the subduction zone of South American Plate since 1993.⑤ The great Chile earthquake shows that the global seismicity is still in the active period of MW≥8.5 earthquakes since 2004.Based on the characteristics of the former two active periods,several MW≥8.5 great earthquakes would take place in a few years.In addition,the circum-Pacific seismic belt would be the main region for MW≥8.0 earthquakes.更多还原