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| Titel |
On the complexity of surface ruptures during normal faulting earthquakes: excerpts from the 6 April 2009 L'Aquila (central Italy) earthquake (Mw 6.3) |
| VerfasserIn |
L. Bonini, D. Di Bucci, G. Toscani, S. Seno, G. Valensise |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1869-9510
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| Digitales Dokument |
URL |
| Erschienen |
In: Solid Earth ; 5, no. 1 ; Nr. 5, no. 1 (2014-05-28), S.389-408 |
| Datensatznummer |
250115275
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| Publikation (Nr.) |
 copernicus.org/se-5-389-2014.pdf |
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| Zusammenfassung |
Over the past few years the
assessment of the earthquake potential of large continental faults has
increasingly relied on field investigations. State-of-the-art seismic hazard
models are progressively complementing the information derived from
earthquake catalogs with geological
observations of active faulting. Using these observations, however, requires
full understanding of the relationships between seismogenic slip at depth and
surface deformation, such that the evidence indicating the presence of a
large, potentially seismogenic fault can be singled out effectively and
unambiguously.
We used observations and models of the 6 April 2009, Mw 6.3,
L'Aquila, normal faulting earthquake to explore the relationships between the
activity of a large fault at seismogenic depth and its surface evidence. This
very well-documented earthquake is representative of mid-size yet damaging
earthquakes that are frequent around the Mediterranean basin, and was chosen
as a paradigm of the nature of the associated geological evidence, along with
observational difficulties and ambiguities.
Thanks to the available high-resolution geologic, geodetic and seismological
data aided by analog modeling, we reconstructed the full geometry of the
seismogenic source in relation to surface and sub-surface faults. We maintain
that the earthquake was caused by seismogenic slip in the range 3–10 km
depth, and that the slip distribution was strongly controlled by inherited
discontinuities. We also contend that faulting was expressed at the surface
by pseudo-primary breaks resulting from coseismic crustal bending and by
sympathetic slip on secondary faults.
Based on our results we propose a scheme of normal fault hierarchization
through which all surface occurrences related to faulting at various depths
can be interpreted in the framework of a single, mechanically coherent model.
We stress that appreciating such complexity is crucial to avoiding severe
over- or under-estimation of the local seismogenic potential. |
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