ISSN:
1573-157X
Keywords:
earthquake
;
normal fault
;
seismic sequence
;
seismotectonics
;
Umbria-Marche Apennines
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Physics
Notes:
Abstract In this study, surface and subsurface geologicaldata are integrated with seismological data in orderto reconstruct a structural model for theSeptember-October 1997 Colfiorito earthquakes. Theseismic sequence is mainly controlled by two majorSW-dipping normal faults outcropping in the area (M.Pennino-M. Prefoglio and M.Civitella-Preci faults).The activated faults detach, at depth, on a commoneast-dipping low-angle normal fault, the AltotiberinaFault (AF). The AF is interpreted as the base of anactive hangingwall block which is stretching towardNE. The decrease in maximum depth of the earthquakefoci from the Colfiorito area (about 8 km) to theSellano area (about 6 km), suggested by the available seismological data, could be related to the eastward-deepening geometry of the AFdetachment. The seismic fault planes, inferred fromfocal mechanisms and aftershock distributions, arecharacterised by a moderate dip (average 40°)toward SW, which appears to be independent from thepresence of pre-existing thrust planes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1026509717771
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