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| Titel |
Great and old earthquakes against great and old paradigms – paradoxes, historical roots, alternative answers |
| VerfasserIn |
G. Scalera |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7340
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| Digitales Dokument |
URL |
| Erschienen |
In: 2nd EGU Alexander von Humboldt Conference "The role of Geophysics in Natural Disaster Prevention" ; Nr. 14 (2008-01-02), S.41-57 |
| Datensatznummer |
250012081
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| Publikation (Nr.) |
 copernicus.org/adgeo-14-41-2008.pdf |
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| Zusammenfassung |
The similarity of the vertical displacements shown by
case-history extreme-magnitude earthquakes are scrutinised (Chile 1960,
Alaska 1964, Sumatra 2004, ...). A common interpretation – an uprising
of lithospheric material – can be found, which is supported by the
irregularities of the hypocentres distribution along the Wadati-Benioff
zones. In the case of major South American earthquakes, a volcanic
eruptions-earthquakes correlation is recognisable.
Further support to this interpretation is the displacement of the Earth's
instantaneous rotation pole – ≈3.0 mas (≈10 cm), observed
at ASI of Matera, Italy – the seismic data (USGS) in the two days following
the main shock, the geomorphologic data, and the satellite data of
uplift/subsidence of the coasts (IGG) make possible a new interpretation of
the Great Sumatran earthquake (26 December 2004) based on the second
conjugate – nearly vertical – CMT fault plane solution.
All this converges toward different causes of seismogenetic processes,
strongly supporting a deep origin of disturbances, fluxes of materials
leading to more or less sudden movements of masses, and phase changes, which
lead to either earthquakes or silent-slow events in Wadati-Benioff zones. A
reinterpretation of the geodynamics of the active margins and mountain
building is proposed with a heuristic model that does not resort to
large-scale subduction, but only to isostatic uplift of deep material
intruding between two decoupling plates in a tensional environment.
Concomitant phase changes toward less-packed lattice and buoyancy effect
caused by the Clapeyron slope can help the extrusion of material over the
m.s.l., constituting an orogenic process. The phenomena expected to occur in
the model directly and harmoniously contribute to the building up of the
surface geophysical and geomorphological features of the orogenic zones. |
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