This article made a systematic statistical analysis on the duration,spatial distribution,form,range,type and reliability of precursory anomalies based on the observations of precursors of 24 moderate-strong earthquake...This article made a systematic statistical analysis on the duration,spatial distribution,form,range,type and reliability of precursory anomalies based on the observations of precursors of 24 moderate-strong earthquakes occurring along the Tancheng-Lujiang fault zone and its bilateral areas in Shandong,Liaoning,Hebei,Jiangsu and Jiangxi Provinces in the period from 1966 to 2005. Results show that:( 1) For M7. 0 and M6. 0earthquakes,med-term abnormities are the greatest in number,short-term abnormities come second,and imminent anomalies are the least. For M5. 0 earthquakes,short-term abnormities are often the most in number,imminent anomalies come second,and the med-term ones are the least.( 2) Precursory anomalies are periodical,part of the med and short-term anomalies are shown as short-term and imminent anomalies during their development.( 3) The development of precursor shows quasi-synchronism; the closer to earthquake occurrence time,the more turning changes of anomalies will appear.( 4)Anomalies mainly occur within an epicenter distance of 100 km, showing a relative concentrated distribution in space,and the shorter the distance to epicenter,the higher the anomaly station / item rate.( 5) The spatial distribution of anomalies is relatively correlated to the strike of structures,having a good consistency with the structure.( 6)There is no significant correlation between duration of abnormities and the epicenter distance.( 7) The higher the magnitude of the earthquake,the greater the amplitude of the abnormities measured with the same observation approach.( 8) In terms of the itemsof the observations,fluid abnormities are the greatest in number,followed by deformation and electromagnetism observations.( 9) For all observation items,med and short-term abnormities make up the majority and short-term and imminent anomalies the minority.( 10) In fluid,deformation and electromagnetism observations,fairly reliable anomalies are about double the number of reliable anomalies.展开更多
Choosing the Jingle well in Shanxi as the research object, this paper discusses the reproducibility problem of well water level precursor waves. The results show that the start time and fluctuation cycle before simila...Choosing the Jingle well in Shanxi as the research object, this paper discusses the reproducibility problem of well water level precursor waves. The results show that the start time and fluctuation cycle before similar earthquakes are highly reproducible,the ratio of which is up to 63. 1%. The fluctuation form and amplitude before some similar earthquakes are of certain similarity,but earthquakes with all precursor wave features being similar were not found in the research scope. The reason may be related to the origin and transmission route of the precursor wave as well as the properties of the seismic source area of similar earthquakes.展开更多
基金supported financially by Science for Earthquake Resilience(XH14064Y)the open foundation of the State Key Laboratory of Geodesy and Earth's Dynamics(SKLGED2014-5-2-E)the major national science and technology support project(2012BAK19B04-05-02)
文摘This article made a systematic statistical analysis on the duration,spatial distribution,form,range,type and reliability of precursory anomalies based on the observations of precursors of 24 moderate-strong earthquakes occurring along the Tancheng-Lujiang fault zone and its bilateral areas in Shandong,Liaoning,Hebei,Jiangsu and Jiangxi Provinces in the period from 1966 to 2005. Results show that:( 1) For M7. 0 and M6. 0earthquakes,med-term abnormities are the greatest in number,short-term abnormities come second,and imminent anomalies are the least. For M5. 0 earthquakes,short-term abnormities are often the most in number,imminent anomalies come second,and the med-term ones are the least.( 2) Precursory anomalies are periodical,part of the med and short-term anomalies are shown as short-term and imminent anomalies during their development.( 3) The development of precursor shows quasi-synchronism; the closer to earthquake occurrence time,the more turning changes of anomalies will appear.( 4)Anomalies mainly occur within an epicenter distance of 100 km, showing a relative concentrated distribution in space,and the shorter the distance to epicenter,the higher the anomaly station / item rate.( 5) The spatial distribution of anomalies is relatively correlated to the strike of structures,having a good consistency with the structure.( 6)There is no significant correlation between duration of abnormities and the epicenter distance.( 7) The higher the magnitude of the earthquake,the greater the amplitude of the abnormities measured with the same observation approach.( 8) In terms of the itemsof the observations,fluid abnormities are the greatest in number,followed by deformation and electromagnetism observations.( 9) For all observation items,med and short-term abnormities make up the majority and short-term and imminent anomalies the minority.( 10) In fluid,deformation and electromagnetism observations,fairly reliable anomalies are about double the number of reliable anomalies.
基金funded by Science and Technology Tackling Project of Shanxi Province ( 2006031106)the Joint Earthquake Science Foundation of China Earthquake Administration( A08051)Natural Sciences Foundation of Shanxi Province ( 2011011027)
文摘Choosing the Jingle well in Shanxi as the research object, this paper discusses the reproducibility problem of well water level precursor waves. The results show that the start time and fluctuation cycle before similar earthquakes are highly reproducible,the ratio of which is up to 63. 1%. The fluctuation form and amplitude before some similar earthquakes are of certain similarity,but earthquakes with all precursor wave features being similar were not found in the research scope. The reason may be related to the origin and transmission route of the precursor wave as well as the properties of the seismic source area of similar earthquakes.
