Please use this identifier to cite or link to this item:
http://hdl.handle.net/2122/3448
Authors: | Chiaraluce, L.* Ellsworth, W.* Chiarabba, C.* Cocco, M.* |
Title: | Imaging the complexity of an active normal fault system: The 1997 Colfiorito (central Italy) case study | Journal: | Journal of Geophysical Research | Series/Report no.: | B6/108 (2003) | Publisher: | American Geophysical Union | Issue Date: | 6-Jun-2003 | DOI: | 10.1029/2002JB002166 | Keywords: | Normal faulting double-difference Umbria-Marche corss-correlation relative location |
Subject Classification: | 05. General::05.02. Data dissemination::05.02.02. Seismological data | Abstract: | Six moderate magnitude earthquakes (5 < Mw < 6) ruptured normal fault segments of the southern sector of the North Apennine belt (central Italy) in the 1997 Colfiorito earthquake sequence. We study the progressive activation of adjacent and nearby parallel faults of this complex normal fault system using1650 earthquake locations obtained by applying a double-difference location method, using travel time picks and waveform cross-correlation measurements. The lateral extent of the fault segments range from 5 to 10 km and make up a broad,45 km long, NW trending fault system. The geometry of each segment is quite simple and consists of planar faults gently dipping toward SW with an average dip of 40–45. The fault planes are not listric but maintain a constant dip through the entire seismogenic volume, down to 8 km depth. We observe the activation of faults on the hanging wall and the absence of seismicity in the footwall of the structure. The observed fault segmentation appears to be due to the lateral heterogeneity of the upper crust: preexisting thrusts inherited from Neogene’s compressional tectonic intersect the active normal faults and control their maximum length. The stress tensor obtained by inverting the six main shock focal mechanisms of the sequence is in agreement with the tectonic stress active in the inner chain of the Apennine, revealing a clear NE trending extension direction. Aftershock focal mechanisms show a consistent extensional kinematics, 70% of which are mechanically consistent with the main shock stress field. |
Appears in Collections: | Article published / in press |
Files in This Item:
File | Description | Size | Format | Existing users please Login |
---|---|---|---|---|
JGR_CHIARALUCE.pdf | 2.27 MB | Adobe PDF |
WEB OF SCIENCETM
Citations
50
119
checked on Feb 10, 2021
Page view(s)
139
checked on Apr 17, 2024
Download(s)
31
checked on Apr 17, 2024