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Titel |
External forcing of earthquake swarms at Alpine regions: example from a seismic meteorological network at Mt. Hochstaufen SE-Bavaria |
VerfasserIn |
V. Svejdar, H. Küchenhoff, L. Fahrmeir, J. Wassermann |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1023-5809
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Digitales Dokument |
URL |
Erschienen |
In: Nonlinear Processes in Geophysics ; 18, no. 6 ; Nr. 18, no. 6 (2011-11-22), S.849-860 |
Datensatznummer |
250013998
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Publikation (Nr.) |
copernicus.org/npg-18-849-2011.pdf |
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Zusammenfassung |
In the last few years, it has been shown that above-average rainfall
and the following diffusion of excess water into subsurface
structures is able to trigger earthquake swarms in the uppermost
brittle portion of the Earth's crust. However, there is still an
ongoing debate on whether the crust already needs to be in a
critical-to-failure state or whether it is sufficient that water is
transported rapidly within channels and veins of karst or similar
geological formations to the underlying, earthquake-generating
layers. Also unknown is the role of other forcing mechanisms,
possible co-variables and probably necessary tectonic loading in the
triggering process of earthquakes. Because of these problems, we do
not use an explicit physical model but instead analyze the
meteorological and geophysical data via sophisticated statistical
models. \newline We are interested in the influence of a more
complete set of possible forcing parameters, including the influence
of synthetic earth tides, on the occurrence of earthquake swarms. In
this context, regression models are the adequate tool, since the
calculation of simple correlations can be confounded by the other
variables. Since our outcome variable (the number of quakes) is a
count, we use Poisson regression models that include the plausible
assumption of a Poisson distribution for the counts. For this study,
we use nearly continuous recordings of a seismic and meteorological
network in the years 2002–2008 at Mt. Hochstaufen in SE-Bavaria.
Our non-linear regression model reveals correlations between
external forces and the triggering of earthquakes. In addition to
the still dominant influence of rainfall, theoretical estimated
tidal tilt show some weak influence on the swarm generation.
However, the influence of the modeled trend functions shows that
rain is by far not the most important forcing mechanism present in
the data. |
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