摘要
基于法国DEMETER卫星ISL探测器升轨数据,统计分析了2005—2009年全球37个Mw≥7.0级地震前后电离层电子浓度变化.结果发现,共有19个地震(51%)前观测到了较为明显的电子浓度异常扰动现象,其中大部分表现为异常增强;观测到的电子浓度异常现象一般出现在震前1～5天内,也有部分地震前出现两次及以上扰动现象.分析表明,在赤道和中低纬地区更容易观测到明显的电子浓度扰动,即异常震例基本发生在纬度±40°以内(18次),更是以±20°内居多(13次).此外,震源深度对电子浓度扰动的影响并不明显,而震级大小则与扰动幅度基本上呈正相关;震前出现的电子浓度异常有时会受到地磁活跃的共同影响,此时的扰动幅度一般较大.地震电离层扰动现象是复杂多变的,需要联合地基和天基手段共同观测,并从机理上加强研究.
Based on the data of French DEMETER satellite,we attempt to make a statistical analysis of variations of electron density before 37 Mw≥7.0earthquakes in the world during January 2005to December 2009.The orbits,recorded in local nighttime by the satellite,were chosen by a range of longitude 20degree and latitude 15degree during the 9days around these earthquakes,with 7days before and 1day after.Among the 37earthquakes,electron density perturbations were detected before 19events,accounting for nearly 51% of the total.The anomalies represent positive before 18events and occurred mostly within 1～6days before the shocks,part of which appeared more than one time.It is more easily to observe the electron density disturbance around the equatorial and low-latitude regions than high latitudes.Thedisturbance amplitude presents a positive correlation with the magnitude of earthquakes basically,while the depth of earthquakes does not show significant relationship with the perturbation.It is noted that before several events,the anomalies were likely associated with the combined effect of earthquakes and geomagnetic activity and revealed a higher disturbance level.As the seismoionospheric coupling process is complex,it is necessary to conduct more observations of multiparameters on the ground,in the atmosphere and ionosphere synchronously.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2014年第2期364-376,共13页
Chinese Journal of Geophysics
基金
科技部国际合作项目"CSES(中国地震电磁卫星)计划第一期研究"(2009DFA21480)资助
关键词
DEMETER卫星
电离层电子浓度
强震
统计分析
DEMETER satellite
Electron density of ionosphere
Great earthquakes
Statistical analysis
