Spectral peaks in electric field at resonance frequencies for seismically excited motion of ions in the Earth’s magnetic field

Kuriki, Mayu; Matsushima, Masaki; Ogawa, Yasuo; Honkura, Yoshimori

doi:10.5047/eps.2011.03.010

Cited by 8 publications

(6 citation statements)

References 22 publications

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“…It is known that electric field variations, generated by circular motion of ions in groundwater under the Earth's geomagnetic field, are observed during the passage of seismic wave. This process is called "seismic dynamo effect" (e.g., Honkura et al, 2009), and the observed frequencies were higher than about 10 Hz (Kuriki et al, 2011). Though the magnetometer has enough sensitivity at 10-20 Hz, no such signatures are discernible in Fig.…”

Section: Initial Arrival and Northward Propagation Of Disturbancesmentioning

confidence: 99%

Giant ionospheric disturbances observed with the SuperDARN Hokkaido HF radar and GPS network after the 2011 Tohoku earthquake

et al. 2012

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Giant ionospheric disturbances induced by the 2011 off the Pacific coast of Tohoku Earthquake (M w 9.0) on 11 March 2011 are studied by using data from the SuperDARN Hokkaido HF radar and GPS receiver network (GEONET) in Japan. The HF radar observations revealed strong disturbances to the north of Hokkaido that propagated northward at velocities of 6.7-1.8 km/s triggered by northward-propagating seismic surface waves. An induction magnetometer in Hokkaido recorded part of the seismic wave propagation from the epicenter. After the passage of the 6.7-1.8 km/s waves the radar observed northward-propagating disturbances (343-136 m/s) due to atmospheric gravity waves (AGW) perhaps excited near the epicenter. Interestingly, the radar first detected peculiar disturbances with periods of about 2-4 min caused by the acoustic resonance. GEONET, which covers the area on the south of the radar field of view, provided total electron content (TEC) data. Comparisons between radar and TEC observations indicate the following: (1) 6.7-1.8 km/s waves observed with the radar do not always have counterparts in TEC. (2) Acoustic waves of 1.3-0.7 km/s identified in TEC are not observed with the radar. (3) Disturbances caused by both AGW and acoustic resonance are simultaneously discernible in both TEC and radar data.

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Section: Initial Arrival and Northward Propagation Of Disturbancesmentioning

confidence: 99%

Giant ionospheric disturbances observed with the SuperDARN Hokkaido HF radar and GPS network after the 2011 Tohoku earthquake

et al. 2012

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“…His numerical result showed that the coseismic magnetic field can reach the order of 0.1 nT, which is detectable. Recently, reports on the observed circularly polarized coseismic electric field [Honkura et al, 2009;Kuriki et al, 2011;Matsushima et al, 2013] provided evidences for the role of the Earth's magnetic field in generating EM disturbances. Moreover, observations of the tsunami-induced magnetic variations [Manoj et al, 2011;Toh et al, 2011;Utada et al, 2011;Ichihara et al, 2013] were further evidences which indicate that the conductive seawater moving across the Earth's magnetic field can also generate observable variations in the magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Induced electromagnetic field by seismic waves in Earth's magnetic field

Gao

Chen

et al. 2014

JGR Solid Earth

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Studied in this article are the properties of the electromagnetic (EM) fields generated by an earthquake due to the motional induction effect, which arises from the motion of the conducting crust across the Earth's magnetic field. By solving the governing equations that couple the elastodynamic equations with Maxwell equations, we derive the seismoelectromagnetic wavefields excited by a single-point force and a double-couple source in a full space. Two types of EM disturbances can be generated, i.e., the coseismic EM field accompanying the seismic wave and the independently propagating EM wave which arrives much earlier than the seismic wave. Simulation of an M w 6.1 earthquake shows that at a receiving location where the seismic acceleration is on the order of 0.1 m/s 2 , the coseismic electric and magnetic fields are on the orders of 1 μV/m and 0.1 nT, respectively, agreeing with the EM data observed in 2008 M w 6.1 Qingchuan earthquake, China, and indicating that the motional induction effect is effective enough to generate observable EM signal. We also simulated the EM signals observed by Haines et al. (2007) which were called the Lorentz fields and cannot be explained by the electrokinetic effect. The result shows that the EM wave generated by a horizontal force can explain the data well, suggesting that the motional induction effect is responsible for the Lorentz fields. The motional induction effect is compared with the electrokinetic effect, showing the overall conclusion that the former dominates the mechanoelectric conversion under low-frequency and high-conductivity conditions while the latter dominates under high-frequency and low-conductivity conditions.

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“…It should be mentioned that there is another mechanism associated with the geomagnetic field. It is the so‐called “seismic dynamo effect” proposed by Honkura and his coauthors (Honkura et al., 2009; Kuriki et al., 2011; Matsushima et al., 2013) and caused by the motion and resonance of groundwater ions in the geomagnetic field. Honkura et al.…”

Section: Discussionmentioning

confidence: 99%

Magnetic Pulsations Triggered by Microseismic Ground Motion

et al. 2021

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The primary aim of monitoring the geomagnetic field is to study the variations in the Earth's main field (Chapman & Bartels, 1940) and solar activity (Smith et al., 2004; Vassiliadis et al., 1990). When continuous geomagnetic data recorded by magnetometers located within limited areas are examined, synchronous changes with an insignificant time lag in those data are generally interpreted to be the result of global effects dominated by the interaction of variations in the Earth's main field with solar activity on a worldwide scale. However, on a local scale, the geomagnetic field can also be disturbed by ground motion (e.g., Breiner, 1964; Eleman, 1965; Gao et al., 2016; Yamazaki, 2012). Honkura et al. (2004) reported that P-wave arrivals could vary electric and magnetic fields near the surface. Although geomagnetic pulsations can be directly triggered by P waves (e.g., Breiner, 1964; Eleman, 1965; Tsegmed et al., 2000; Yamazaki, 2012), those pulsations are small and close to the amplitude of background noise (Guglielmi et al., 2004). Guglienlmi et al. (2004) recognized magnetic disturbances triggered by Love waves using a polarization method against background noise. On the other hand, disturbances to the geomagnetic field can also be either generated by Rayleigh waves due to ground motion induced by wave arrivals or excited by acoustic waves that are vertically propagating into the atmosphere and changing the electron contents in the ionosphere (Liu et al., 2016; Lognonné et al., 1998; Occhipinti et al., 2010). All the above-mentioned magnetic signals induced by the seismic waves are just local responses and restricted within the passage of the seismic waves. In contrast to the global effect, the geomagnetic changes reported above usually show significant time differences for the related signals retrieved from adjacent stations. The conversion from a seismic wave to a magnetic disturbance can be caused by several mechanoelectric mechanisms. Both theoretical modelings (e.g.

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Spectral peaks in electric field at resonance frequencies for seismically excited motion of ions in the Earth’s magnetic field

Cited by 8 publications

References 22 publications

Giant ionospheric disturbances observed with the SuperDARN Hokkaido HF radar and GPS network after the 2011 Tohoku earthquake

Giant ionospheric disturbances observed with the SuperDARN Hokkaido HF radar and GPS network after the 2011 Tohoku earthquake

Induced electromagnetic field by seismic waves in Earth's magnetic field

Magnetic Pulsations Triggered by Microseismic Ground Motion

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