Geomagnetic Transfer Functions in Japan Obtained by First Order Geomagnetic Survey.

Furwara, Satoshi; Tou, Hiroaki

doi:10.5636/jgg.48.1071

Cited by 15 publications

(23 citation statements)

References 26 publications

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“…It can be seen that the two different methods provide similar results at TNB and SBA, consistent with Fujiwara and Tou (1996), with the respective arrows pointing almost perpendicularly to the nearest coastline. Regarding the horizontal transfer functions at TNB and SBA, we show the real and imaginary parts of each transfer function (Eq.…”

Section: Vertical and Horizontal Transfer Functions Using The Interstsupporting

confidence: 73%

“…In this formula, where f indicates the frequency, the induction effects on the horizontal components are negligible (i.e., X s (f ) and Y s (f ) are the normal field variations). The contribution of anomalies to the vertical and horizontal geomagnetic field can be estimated by using the so-called interstation transfer functions (Schmucker, 1964;Beamish, 1982;Fujiwara and Tou, 1996;Vujić and Brkić, 2016;Harada et al, 2005). Let us assume the following:…”

Section: Data Analysis and Methodsmentioning

confidence: 99%

“…(2) of Jones (1981), where γ 2 represents the magnitude squared coherence between horizontal components at a reference site (X r and Y r if interstation method is used; Eqs. (4)-(9) in Fujiwara and Tou, 1996), or at any site (X s and Y s if singlestation method is used; Sect. 3.1 in Everett and Hyndman, 1967).…”

Section: Data Analysis and Methodsmentioning

confidence: 99%

“…The transfer functions A, B, C +1, D, E and F +1 of tensor M can be estimated as in Everett and Hyndman (1967) (see also Banks (1973) and Fujiwara and Tou (1996) for detailed formulas and different estimation methods).…”

Section: Data Analysis and Methodsmentioning

confidence: 99%

“…As pointed out by Schmucker (1970) and Viljanen et al (1995) (see also Fujiwara and Tou, 1996;Beamish, 1982;Vujić and Brkić, 2016), a suitable analysis in both vertical and horizontal components can be assessed by using a reference station, which should be ideally far away from the ground anomalies (i.e., from the coast). In this regard, we used as a reference station the temporary installation at Talos Dome (TLD, ∼ 80 • S), deployed during the 2007-2008 Antarctic campaign at ∼ 270 and 560 km from TNB and SBA, respectively, and operating during 18 January-14 March 2008 (Lepidi et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

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The geomagnetic coast effect at two 80° S stations in Antarctica, observed in the ULF range

et al. 2018

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Abstract. We examined the coast effect in Antarctica along the 80 • S magnetic parallel. We used the geomagnetic field measurements at the two coastal stations of Mario Zucchelli Station and Scott Base, and, as a reference, at the inland temporary station Talos Dome, during 18 January-14 March 2008. Spectral analysis in the Pc5 frequency range (1-7 mHz) revealed large differences between coastal and inland stations, such as higher spectral power levels in the vertical component and higher coherence between horizontal and vertical components at coastal stations. Using the interstation method on selected active time intervals, with Talos Dome as a remote reference station, we found that remote reference induction arrows are directed almost perpendicularly with respect to their respective coastlines. Moreover, the singlestation analysis shows that at Talos Dome the amplitude of the induction arrows is much smaller than at coastal stations. These results clearly indicate that coast effect at a few hundred kilometers from the coastline is relatively small. The coast effect on polarization parameters was examined, for a Pc5 event that occurred on 11 March 2008. The results evidenced that the azimuthal angle of polarized signals at one of the coastal stations is largely different with respect to the inland station (by ∼ 110 • ), while the polarization ratio and ellipticity attain comparable values. We proposed a correction method of the polarization parameters, which operates directly in the frequency domain, obtaining comparable azimuthal angles at coastal and inland stations.

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Section: Vertical and Horizontal Transfer Functions Using The Interstsupporting

confidence: 73%

Section: Data Analysis and Methodsmentioning

confidence: 99%

Section: Data Analysis and Methodsmentioning

confidence: 99%

Section: Data Analysis and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The geomagnetic coast effect at two 80° S stations in Antarctica, observed in the ULF range

et al. 2018

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3‐D electrical resistivity structure based on geomagnetic transfer functions exploring the features of arc magmatism beneath Kyushu, Southwest Japan Arc

et al. 2017

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Our 3‐D electrical resistivity model clearly detects particular subsurface features for magmatism associated with subduction of the Philippine Sea Plate (PSP) in three regions: a southern and a northern volcanic region, and a nonvolcanic region on the island of Kyushu. We apply 3‐D inversion analyses for geomagnetic transfer function data of a short‐period band, in combination with results of a previous 3‐D model that was determined by using Network‐Magnetotelluric response function data of a longer‐period band as an initial model in the present inversion to improve resolution at shallow depths; specifically, a two‐stage inversion is used instead of a joint inversion. In contrast to the previous model, the presented model clearly reveals a conductive block on the back‐arc side of Kirishima volcano at shallow depths of ~50 km; the block is associated with hydrothermal fluids and hydrothermal alteration zones related to the formation of epithermal gold deposits. A second feature revealed by the model is another conductive block regarded as upwelling fluids, extending from the upper surface of the PSP in the mantle under Kirishima volcano in the southern volcanic region. Third, a resistive crustal layer, which confines the conductive block in the mantle, is distributed beneath the nonvolcanic region. Fourth, our model reveals a significant resistive block, which extends below the continental Moho at the fore‐arc side of the volcanic front and extends into the nonvolcanic region in central Kyushu.

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Global signal classification of ULF geomagnetic field variations using interstation transfer function

2005

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SUMMARYIn order to study earthquake-related ULF geomagnetic field changes, it is important to discriminate the signal from the other noises such as magnetic pulsations originated from solar activity and artificial noises from the DC driven train and factories. For this goal, the interstation transfer function method with wavelet transform has been applied to data observed in the ULF electromagnetic sensor array at Boso Peninsula, Japan. The results indicate that the proposed method has the capacity to eliminate the global signal.

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Geomagnetic Transfer Functions in Japan Obtained by First Order Geomagnetic Survey.

Cited by 15 publications

References 26 publications

The geomagnetic coast effect at two 80° S stations in Antarctica, observed in the ULF range

The geomagnetic coast effect at two 80° S stations in Antarctica, observed in the ULF range

3‐D electrical resistivity structure based on geomagnetic transfer functions exploring the features of arc magmatism beneath Kyushu, Southwest Japan Arc

Global signal classification of ULF geomagnetic field variations using interstation transfer function

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