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| Titel |
Influence of high-latitude geomagnetic pulsations on recordings of broadband force-balanced seismic sensors |
| VerfasserIn |
E. Kozlovskaya, A. Kozlovsky |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
2193-0856
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Instrumentation, Methods and Data Systems ; 1, no. 2 ; Nr. 1, no. 2 (2012-08-17), S.85-101 |
| Datensatznummer |
250000163
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| Publikation (Nr.) |
 copernicus.org/gi-1-85-2012.pdf |
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| Zusammenfassung |
| Seismic broadband sensors with electromagnetic feedback are sensitive to
variations of surrounding magnetic field, including variations of
geomagnetic field. Usually, the influence of the geomagnetic field on
recordings of such seismometers is ignored. It might be justified for
seismic observations at middle and low latitudes. The problem is of high
importance, however, for observations in Polar Regions (above 60°
geomagnetic latitude), where magnitudes of natural magnetic disturbances may
be two or even three orders larger. In our study we investigate the effect
of ultra-low frequency (ULF) magnetic disturbances, known as geomagnetic
pulsations, on the STS-2 seismic broadband sensors. The pulsations have
their sources and, respectively, maximal amplitudes in the region of the
auroral ovals, which surround the magnetic poles in both hemispheres at
geomagnetic latitude (GMLAT) between 60° and 80°. To investigate
sensitivity of the STS-2 seismometer to geomagnetic pulsations, we compared
the recordings of permanent seismic stations in northern Finland to the data
of the magnetometers of the IMAGE network located in the same area. Our
results show that temporary variations of magnetic field with periods of
40–150 s corresponding to regular Pc4 and irregular Pi2 pulsations are seen
very well in recordings of the STS-2 seismometers. Therefore, these
pulsations may create a serious problem for interpretation of seismic
observations in the vicinity of the auroral oval. Moreover, the shape of Pi2
magnetic disturbances and their periods resemble the waveforms of glacial
seismic events reported originally by Ekström (2003). The problem may be
treated, however, if combined analysis of recordings of co-located seismic
and magnetic instruments is used. |
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