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| Titel |
Automatic identification, localisation and volume estimation of rockfalls occurring in the Dolomieu crater, Piton de la Fournaise volcano, la Réunion Island. |
| VerfasserIn |
Clément Hibert, Anne Mangeney, Gilles Grandjean, Chrisitian Baillard, Wayne Crawford, Valérie Ballu, Nikolai Shapiro |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250078465
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| Zusammenfassung |
| The permanent seismic network set up on the Piton de la Fournaise volcano by the
Observatoire Volcanologique du Piton de la Fournaise (OVPF) is particularly well suited to
studying seismic signals generated by slope instabilities related to volcanic activity. Hundred
seismic signals generated by rockfalls that occurred in the Dolomieu crater are studied to
assess the links between the processes that trigger the rockfalls, their intrinsic properties and
the associated seismic signals. For the study of these processes and the spatio-temporal
evolution of the rockfall activity over a long period of time, it is necessary to have automatic
methods to process the large amount of data available. We present a method which aims
to automatically discriminate seismic signals generated by rockfalls from those
recorded by the OVPF seismological network. A kurtosis-based automatic picking
method makes it possible to precisely pick the onset time and the final time of the
rockfall generated seismic signals, despite their peculiarity. We then established
localisation methods based on these precise picking, and a surface wave propagation
model computed for each station from a Fast Marching Method. These methods
have successfully localized rockfalls which were directly observed. This set of
methods makes it possible the study of a database of 12422 rockfalls that occurred
during a period going from May 2007 to May 2011, from the Dolomieu crater floor
collapse to the end of the UDNERVOLC project. This study reveals that the number
and moreover the volume of the rockfalls is an important information to take into
account to determine wether an intrusive process will end as a summit eruption or not. |
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