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Coseismic and postseismic displacements related with the 1997 Earthquake Sequence in Umbria‐Marche (Central Italy)
Author(s) -
Basili Roberto,
Meghraoui Mustapha
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl012102
Subject(s) - geology , seismology , geodesy , slip (aerodynamics) , fault (geology) , displacement (psychology) , aqueduct , deformation (meteorology) , surface rupture , vertical displacement , geomorphology , psychology , history , oceanography , physics , archaeology , psychotherapist , thermodynamics
We study the coseismic and postseismic displacements related with the 1997 Umbria‐Marche earthquake sequence by means of leveling lines along a deformed aqueduct located in the epicentral area. Comparing the 1960 and 10/1997 measurements we obtain 0.49±0.10 m of coseismic displacement distributed along 3 km across the normal fault zone. Modeling of the coseismic surface dislocation is obtained from a combination of low angle (38°) faults at depth and high angle (80°) upper fault branches. The best fit model indicates that the upper branches stop at 0.4 km below the ground surface and have 60% of slip with respect to the lower faults. The postseismic displacement measured during 1998 is 0.18 m and represents 36% of the apparent coseismic deformation. Moderate earthquakes in the Apennines and related surface deformation may thus result from curved faults that reflect the brittle‐elastic properties of the uppermost crustal structures.