摘要
介绍了近年来国内外对震前电离层异常扰动研究进展,大量新的观测证据显示,地震活动前的电离层扰动确实存在,而且在震级大于5级的地震发生前几天到几个小时内的孕震区上空会发生显著电离层扰动。针对2008年5月12日发生的里氏8.0级汶川大地震事件,通过利用漠河、北京、武汉和三亚的地基GPS测量获得的垂直电子总含量(VTEC)数据,北京地面测高仪测量的F_2层临界频率和Es临界频率等参量,考察中国上空电离层在地震前的变化情况,发现地震前1～6 d中,5月6-7,10-11日,白天电子浓度比5月1-5日的值偏低。但f_0E_s增强。5月9日日落后中低纬电子浓度出现异常增强,而这段时间地磁活动平静。探求这些异常变化的机制则需收集更多资料做进一步的研究。
This paper first reports the recent progress in the investigation of ionospheric precursor of earthquake, which indicates that ionospheric disturbance do appear few days or hours prior to earthquake. Then, the ionospheric parameters such as Total Electron Content （TEC） derived from four GPS receivers at Mohe, Beijing, Wuhan and Sanya, F2 and Es layer critical frequency （f0F2 and f0Es） observed from the Beijing ground ionosonde were used to examine the ionospheric variation before the Wenchuan M8.0 earthquake. Results show that 1-6 days before the earthquake during May 6th-7th, 10th-11th, daytime value of electron content was generally lower than that during May 1st-5th, while foEs was enhanced. In comparison, the TEC and f0F2 experienced a significant increase on May 9th around sunset sector while the geomagnetic activity was low. It is still unknown whether these ionospheric disturbances were related to the earthquake or not. Further study is needed to explore the mechanisms of these ionospheric anomalous disturbances.
出处
《科技导报》
CAS
CSCD
2008年第11期30-34,共5页
Science & Technology Review
基金
国家自然科学基金项目(40636032)
关键词
地震
电离层异常
前兆
Wenchuan earthquake
ionospheric anomalies
precursor
