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Titel |
In-situ calibration of seismic sensors recording differential motion to determine rotational ground motion components |
VerfasserIn |
Jiří Málek, Johana Brokesova, Petr Kolínský |
Konferenz |
EGU General Assembly 2010
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 12 (2010) |
Datensatznummer |
250036901
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Zusammenfassung |
We present an effective in situ calibration of paired sensor records used to determine
differential seismic motions. The calibration is of extreme importance when small differential
motions are to be recorded, which requires the paired sensors to be ‘identical’ in terms of
their frequency characteristics. These differential motions are subsequently used to derive
finite differences approximating spatial derivatives appearing in the expressions for seismic
rotations. The calibration method is applicable only when the differential motions are
over-determined, i.e. the same difference is measured by more than one pair of sensors of the
same type. We demonstrate the calibration method on three illustrative examples: a synthetic
test, a series of laboratory tests using a special rotational shaking table, and a measurement of
vertical rotation rate due to a small earthquake of ML=2.7, which occurred within the
earthquake swarm in Western Bohemia in autumn 2008. We found good agreement of the
calibrated rotation record with the transverse acceleration as predicted by theory. |
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