搜索结果: 1-15 共查到“理学 ULF”相关记录38条 . 查询时间(0.061 秒)
云南景谷MS6.6地震前地磁ULF异常信号变化
地震 ULF异常信号 景谷
2019/1/4
采用云南地磁台站通海、景谷、勐腊磁通门记录秒采样数据，分析了3个台站当地时间22时到次日2时（世界时15-19时）之间垂直分量（Z）和水平分量（H）在特定0.01~0.05 Hz范围的辐射谱强度。结果表明，在震前垂直分量并没有强烈和清晰的ULF信号强度，3个台站水平分量ULF信号趋势性上升和震时反常的信号衰减现象，则反映震前超低频地磁信号产生扰动。
ULF geomagnetic field measurements in Antarctica are a very important tool for better understanding the dynamics of the Earths magnetosphere and its response to the variable solar wind conditions. We ...
Preseismic ULF effectand possible interpretation
Ultra-Low Frequency emission seismicity Alfven waves
2015/9/14
We present the results of ULF magnetic field observation at Karimshino station (Kamchatka, Russia). Using a case study we discovered an effect of suppression of ULF intensity about 2-6 days before rat...
A possible model for initiationof ULF oscillation in magma
ULF oscillations magma volcano electromagnetic emission
2015/9/14
During the period just prior to an earthquake, an electomagnetic emission develops over seismic zones. In this paper, a model of excitation of magnetic fields over zones of volcanic activity is propos...
Depression of the ULF geomagnetic pulsation related to ionospheric irregularities
ULF ionosphere Alfven seismicity
2015/9/14
We consider a depression in intensity of ULF magnetic pulsations, which is observed on the ground surface due to appearance of the irregularities in the ionosphere. It is supposed that oblique Alfven ...
The study of local sources of ULF geoelectric signals with steep fronts
geoelectricity earthquakes prediction method VAN
2015/9/14
The method for recognition and monitoring of ULF electrotelluric signals with steep fronts is presented. The method is based on the multicomponent measurements of the geoelectric field and recognition...
2004年8月3日近地TC-1卫星在磁尾XGSM~－12RE的等离子体片内,观测到了伴随着高速流的低于离子回旋频率的波,即超低频波(ULF,Ultra Low Frequency).该波垂直分量的振幅在高速流及其振荡减速期间大致相当;而平行分量振幅在高速流时明显大于其振荡减速时. 利用一个扰动双流模型对完全磁化离子横场漂移驱动的电磁不稳定性计算后,预测结果表明:(1)对于垂直分量来说,横场漂移速度...
汶川MS8.0级地震前后ULF电磁辐射频谱特征研究
汶川地震 电磁辐射 ULF频段 快速傅里叶变换(FFT) 小波变换
2013/11/4
本文基于电磁波频谱理论研究方法,对2008年四川汶川MS8.0地震前后金河、剑阁及郑州二砂三个电磁波台站的观测资料进行FFT和小波变换分析,研究了电磁辐射数据快速傅里叶频谱变化特征和在不同尺度下小波变化的分解,发现在汶川地震前确实有异常信息存在.结果表明:(1) FFT动态谱图像说明,地震前电磁波频谱变化特征较明显,在时间、频段上均显示了阶段性进程特征,且随着震中距的增大,辐射能量越小,异常出现的...
2007年3月3日长时间持续Pc5 ULF波的多点联合观测分析
Pc5 ULF 波 剪切Alfven波 压缩波 磁层
2013/11/5
2007年3月3日位于磁层昏侧THEMIS的5颗卫星、同步轨道晨侧和午前的GOES 3颗卫星和地面地磁台站同时观测到了持续近4 h的Pc5 ULF波.我们用交叉小波相关分析计算脉动的传播速度,用MVA分析求解脉动的传播方向,然后结合两者的计算结果获得了Pc5相速度矢量信息.THEMIS卫星观测到Pc5具有压缩特性,且向阳传播,速度约在6~20 km/s左右,相比于磁层中阿尔芬速度(1000 km/...
Application of polarization ellipse technique for analysis of ULF magnetic fields from two distant stations in Koyna-Warna seismoactive region, West India
Application polarization ellipse technique analysis ULF
2010/10/21
A new approach is developed to find the source azimuth of the ultra low frequency (ULF) electromagnetic (EM) signals believed to be emanating from well defined seismic zone. The method is test applied...
Investigation of ULF magnetic pulsations,air conductivity changes,and infra red signatures associated with the 30 October Alum Rock M5.4 earthquake
ULF magnetic pulsations air conductivity changes infra red signatures
2009/12/16
Several electromagnetic signal types were observed prior to and immediately after 30 October 2007 (Local Time) M5.4 earthquake at Alum Rock, Ca with an epicenter ~15 km NE of San Jose Ca. The area whe...
A direction finding technique for the ULF electromagnetic source
direction finding technique ULF electromagnetic source
2009/12/14
A technique of direction finding is proposed, which can be applied to the magnetic-dipole type source located in the conductive ground. To distinguish a weak ULF source signal from the natural noise a...
Analysis of the ULF electromagnetic emission related to seismic activity, Teoloyucan geomagnetic station, 1998-2001
the ULF electromagnetic emission seismic activity Teoloyucan geomagnetic station
2009/12/14
Results of ULF geomagnetic measurements at station Teoloyucan (Central Mexico, 99.11'35.735''W, 19.44'45.100''N, 2280m height) in relation to seismic activity in the period 1998-2001 and their analysi...
On the nature,scaling and spectral properties of pre-seismic ULF signals
nature scaling spectral properties pre-seismic ULF signals
2009/12/11
Earlier work by the authors (Vallianatos and Tzanis, 1999b), has proposed a model for the propagation and scaling of electric earthquake precursors, according to which the pre-seismic electric field e...
Fractal analysis of the ULF geomagnetic data obtained at Izu Peninsula,Japan in relation to the nearby earthquake swarm of June–August 2000
Fractal analysis ULF geomagnetic data Izu Peninsula nearby earthquake swarm
2009/12/11
In our recent papers we applied fractal methods to extract the earthquake precursory signatures from scaling characteristics of the ULF geomagnetic data, obtained in a seismic active region of Guam Is...