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Ionospheric perturbations before Pu’er earthquake observed on DEMETER 被引量:21
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作者 朱荣 杨冬梅 +2 位作者 荆凤 杨俊英 欧阳新艳 《地震学报》 CSCD 北大核心 2008年第1期76-81,共6页
A destructive shock with magnitude of 6.3 occurred on 2 June 2007 at 21h34min56s UT in Pu’er region (23.0°N, 101.1°E), Yunnan Province, China. The data from DEMETER satellite during the period from 23 May t... A destructive shock with magnitude of 6.3 occurred on 2 June 2007 at 21h34min56s UT in Pu’er region (23.0°N, 101.1°E), Yunnan Province, China. The data from DEMETER satellite during the period from 23 May to 2 June, i.e., ten days before the earthquake and one day just on the day of earthquake occurrence, were analyzed. Among the 284 orbits of DEMETER during the period, 29 orbits with the trace passing through the region within 1 888 km from the epicenter were selected to be studied. Seven anomalous events were found on the dataset of the seven orbits among the 29 ones. There existed synchronous perturbations on the variations of the spectrogram of the electric field and the variations of the density and temperature of the ions and electron, in contrast with the variations of its surround- ing area. And five events appeared in the space within 1 888 km from the epicenter while the other two were out of the studied area. Electrostatic turbulences were also recorded with the synchronous perturbations with that in the electron density and ions density in plasma in the region near the epicenter in the five events, which seems to sug- gest that there be some physical relation between these events and the preparation processes of Pu’er earthquake. 展开更多
关键词 demeter 普洱地震 电离层前兆
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Anomaly of the ionospheric electron density close to earthquakes:Case studies of Pu'er and Wenchuan earthquakes
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作者 Yufei He Dongmei Yang +1 位作者 Jiadong Qian Michel Parrot 《Earthquake Science》 CSCD 2011年第6期549-555,共7页
The electron density recorded onboard the DEMETER satellite was analyzed to search for possible anomalies before earthquakes both in space and time. To distinguish pre-earthquake anomalies from the other anomalies rel... The electron density recorded onboard the DEMETER satellite was analyzed to search for possible anomalies before earthquakes both in space and time. To distinguish pre-earthquake anomalies from the other anomalies related to geomagnetic activity, data were filtered using the Kp index. The analysis is based on the comparison of data recorded closely to earthquakes in space and time and past data for the same area. In analyzing data around the time and location of the Pu'er and Wenchuan earthquakes, obvious anomalies in electron density were found close to the epicenters, and some remarkable disturbances were detected before the earthquakes occurred. The results were finally compared with those of previous works that used the same data but employed different analysis methods. Good agreement was found which suggests that these anomalies have a close relation to the earthquake preparation. 展开更多
关键词 Wenchuan earthquake pu'er earthquake electron density demeter satellite ANOMALY
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2005年3月28日苏门答腊8.6级地震前的电离层扰动(英文) 被引量:18
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作者 张学民 刘静 +5 位作者 申旭辉 M.Parrot 钱家栋 欧阳新艳 赵庶凡 黄建平 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2010年第3期567-575,共9页
2005年3月28日苏门答腊发生8.6级地震,通过分析处在地磁活动平静期的震前15天的数据,发现3月20、22、23和28日在赤道区域多个参量上出现电离层扰动,如电场和等离子体参量,认为这些电离层扰动可能与本次强震有关.震前电子密度异常有两种... 2005年3月28日苏门答腊发生8.6级地震,通过分析处在地磁活动平静期的震前15天的数据,发现3月20、22、23和28日在赤道区域多个参量上出现电离层扰动,如电场和等离子体参量,认为这些电离层扰动可能与本次强震有关.震前电子密度异常有两种形态,一种是在原来的峰值变化区电子密度单调增加,幅度超过1σ,如3月20日和28日的异常;另外一种是改变了原来在赤道区的单峰变化形态,而呈现了双峰值和赤道谷值的变化形态,如3月22日和23日的扰动.分析结果显示,这两种形态的电子密度扰动都分布在一个比较大的范围内,经度上跨越100°,纬度范围30°,显示了比较长的异常持续时间和全球变化特性.VLF频段电场频谱的数据分析表明双峰形态的扰动不是磁共轭效应.同时低频电场扰动相对电子密度而言集中在一个相对小范围内,当N_e单调上升时,电场扰动却只出现在离震中最近的轨道上.分析认为震源产生的电场信号直接传播进入电离层是非常困难的,但是它可以通过岩石层-大气层-电离层圈层耦合机制造成电离层扰动.结合离子成分及其变化形态的分析,震前氧离子变化形态与氢、氦离子的形态相反,这与其他地震前的电离层异常扰动形态是类似的.综合分析认为,对于与地震相关的电离层异常的识别需要结合多个观测参量的联合分析. 展开更多
关键词 苏门答腊地震 demeter 电离层扰动 电场
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普洱地震前电离层电子密度扰动变化研究 被引量:16
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作者 欧阳新艳 张学民 +4 位作者 申旭辉 刘静 钱家栋 蔡晋安 赵庶凡 《地震学报》 CSCD 北大核心 2008年第4期424-436,共13页
挑选普洱地震前邻近地震震中的3条轨道的电子密度(Ne)数据,分析其1年内的所有重访轨道,并提取了这次地震前的Ne前兆异常.结果表明:①夜间电离层Ne存在明显的季节变化,4个季节呈现了各自不同的变化形态;②Ne的主要变化形态有3种,即单峰... 挑选普洱地震前邻近地震震中的3条轨道的电子密度(Ne)数据,分析其1年内的所有重访轨道,并提取了这次地震前的Ne前兆异常.结果表明:①夜间电离层Ne存在明显的季节变化,4个季节呈现了各自不同的变化形态;②Ne的主要变化形态有3种,即单峰、马鞍和平缓状,这些形态在各个季节都可能出现,但每个季节有相对集中的形态;③Ne空间图象在震前30天内在震中区附近形成高值,异常信息在空间和时间上都与地震分布有很好的相关性,反映空间出现的异常信息确与本次地震有关;④Ne重访轨道曲线形态有一定的相似性,可以为识别判定地震异常提供背景信息. 展开更多
关键词 普洱地震 demeter卫星 电子密度(Ne) 季节变化 地震异常
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