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| Titel |
Multi-parametric investigation of the volcano-hydrothermal system at Tatun Volcano Group, Northern Taiwan |
| VerfasserIn |
S. Rontogianni, K. I. Konstantinou, C.-H. Lin |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 12, no. 7 ; Nr. 12, no. 7 (2012-07-19), S.2259-2270 |
| Datensatznummer |
250010991
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| Publikation (Nr.) |
 copernicus.org/nhess-12-2259-2012.pdf |
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| Zusammenfassung |
| The Tatun Volcano Group (TVG) is located in northern Taiwan near the capital
Taipei. In this study we selected and analyzed almost four years (2004–2007)
of its seismic activity. The seismic network established around TVG
initially consisted of eight three-component seismic stations with this
number increasing to twelve by 2007. Local seismicity mainly involved high
frequency (HF) earthquakes occurring as isolated events or as part of
spasmodic bursts. Mixed and low frequency (LF) events were observed during
the same period but more rarely. During the analysis we estimated duration
magnitudes for the HF earthquakes and used a probabilistic non-linear method
to accurately locate all these events. The complex frequencies of LF events
were also analyzed with the Sompi method indicating fluid compositions
consistent with a misty or dusty gas. We juxtaposed these results with
geochemical/temperature anomalies extracted from fumarole gas and rainfall
levels covering a similar period. This comparison is interpreted in the
context of a model proposed earlier for the volcano-hydrothermal system of
TVG where fluids and magmatic gases ascend from a magma body that lies at
around 7–8 km depth. Most HF earthquakes occur as a response to stresses
induced by fluid circulation within a dense network of cracks pervading the
upper crust at TVG. The largest (ML ~ 3.1) HF event that occurred
on 24 April 2006 at a depth of 5–6 km had source characteristics compatible
with that of a tensile crack. It was followed by an enrichment in magmatic
components of the fumarole gases as well as a fumarole temperature increase,
and provides evidence for ascending fluids from a magma body into the
shallow hydrothermal system. This detailed analysis and previous physical
volcanology observations at TVG suggest that the region is volcanically
active and that measures to mitigate potential hazards have to be considered
by the local authorities. |
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