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首页> 外文期刊>Natural hazards and earth system sciences >The Pulse Azimuth effect as seen in induction coil magnetometers located in California and Peru 2007-2010, and its possible association with earthquakes
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The Pulse Azimuth effect as seen in induction coil magnetometers located in California and Peru 2007-2010, and its possible association with earthquakes

机译：从2007年至2010年在加利福尼亚和秘鲁的感应线圈磁力计中看到的脉冲方位角效应及其与地震的关联

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The QuakeFinder network of magnetometers has recorded geomagnetic field activity in California since 2000. Established as an effort to follow up observations of ULF activity reported from before and after the M Combining double low line 7.1 Loma Prieta earthquake in 1989 by Stanford University, the QuakeFinder network has over 50 sites, fifteen of which are high-resolution QF1005 and QF1007 systems. Pairs of high-resolution sites have also been installed in Peru and Taiwan. Increases in pulse activity preceding nearby seismic events are followed by decreases in activity afterwards in the three cases that are discussed here. In addition, longer term data is shown, revealing a rich signal structure not previously known in QuakeFinder data, or by many other authors who have reported on pre-seismic ULF phenomena. These pulses occur as separate ensembles, with demonstrable repeatability and uniqueness across a number of properties such as waveform, angle of arrival, amplitude, and duration. Yet they appear to arrive with exponentially distributed inter-arrival times, which indicates a Poisson process rather than a periodic, i.e., stationary process. These pulses were observed using three-axis induction coil magnetometers that are buried 1-2 m under the surface of the Earth. Our sites use a Nyquist frequency of 16 Hertz (25 Hertz for the new QF1007 units), and they record these pulses at amplitudes from 0.1 to 20 nano-Tesla with durations of 0.1 to 12 s. They are predominantly unipolar pulses, which may imply charge migration, and they are stronger in the two horizontal (north-south and east-west) channels than they are in the vertical channels. Pulses have been seen to occur in bursts lasting many hours. The pulses have large amplitudes and study of the three-axis data shows that the amplitude ratios of the pulses taken from pairs of orthogonal coils is stable across the bursts, suggesting a similar source. This paper presents three instances of increases in pulse activity in the 30 days prior to an earthquake, which are each followed by steep declines after the event. The pulses are shown, methods of detecting the pulses and calculating their azimuths is developed and discussed, and then the paper is closed with a brief look at future work.
机译：QuakeFinder磁力计网络自2000年以来已记录了加利福尼亚州的地磁场活动。该活动的建立是为了跟踪1989年由斯坦福大学M合并双低线7.1 Loma Prieta地震发生之前和之后报告的ULF活动，QuakeFinder网络拥有50多个站点，其中15个是高分辨率QF1005和QF1007系统。在秘鲁和台湾也已安装了几对高分辨率站点。在此处讨论的三种情况下，附近地震事件发生前脉冲活动增加，随后活动减少。此外，还显示了更长期的数据，揭示了QuakeFinder数据中以前未知的丰富信号结构，或者显示了地震前超低频现象的许多其他作者所发表的信息。这些脉冲作为单独的集合出现，在许多特性（例如波形，到达角度，幅度和持续时间）上具有可证明的可重复性和唯一性。然而它们似乎以指数分布的到达时间到达，这表明泊松过程而不是周期性的，即静止过程。使用埋在地球表面下1-2 m的三轴感应线圈磁力计观察到了这些脉冲。我们的站点使用的奈奎斯特频率为16赫兹（新的QF1007单元为25赫兹），并且记录这些脉冲的幅度为0.1到20纳米特斯拉，持续时间为0.1到12 s。它们主要是单极性脉冲，可能暗示电荷迁移，并且在两个水平（南北和东西方向）通道中比在垂直通道中更强。已经发现脉冲持续多个小时发生。脉冲具有较大的振幅，对三轴数据的研究表明，从正交线圈对中获取的脉冲的振幅比在整个脉冲串中是稳定的，表明存在类似的信号源。本文介绍了地震前30天内脉搏活动增加的三种情况，每一种情况在地震发生后均急剧下降。示出了脉冲，提出并讨论了检测脉冲和计算其方位角的方法，然后在本文的结尾部分简要介绍了未来的工作。

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