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| Titel |
Study of structural change in volcanic and geothermal areas using seismic tomography |
| VerfasserIn |
Najwa Mhana, Gillian Foulger, Bruce Julian, Christine Peirce |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250087110
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| Publikation (Nr.) |
 EGU/EGU2014-1127.pdf |
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| Zusammenfassung |
| Long Valley caldera is a large silicic volcano. It has been in a state of volcanic and seismic
unrest since 1978. Farther escalation of this unrest could pose a threat to the 5,000 residents
and the tens of thousands of tourists who visit the area. We have studied the crustal
structure beneath 28 km X 16 km area using seismic tomography. We performed
tomographic inversions for the years 2009 and 2010 with a view to differencing it
with the 1997 result to look for structural changes with time and whether repeat
tomography is a capable of determining the changes in structure in volcanic and
geothermal reservoirs. Thus, it might provide a useful tool to monitoring physical
changes in volcanoes and exploited geothermal reservoirs. Up to 600 earthquakes,
selected from the best-quality events, were used for the inversion. The inversions were
performed using program simulps12 [Thurber, 1983]. Our initial results show that
changes in both V p and V s were consistent with the migration of CO2 into the
upper 2 km or so. Our ongoing work will also invert pairs of years simultaneously
using a new program, tomo4d [Julian and Foulger, 2010]. This program inverts for
the differences in structure between two epochs so it can provide a more reliable
measure of structural change than simply differencing the results of individual years. |
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