Earth-prints repository, logo   DSpace

About DSpace Software
|earth-prints home page | roma library | bologna library | catania library | milano library | napoli library | palermo library
Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/5908

Authors: Di Luccio, F.*
Ventura, G.*
Di Giovambattista, R.*
Piscini, A.*
Cinti, F. R.*
Title: Normal faults and thrusts re-activated by deep fluids: the 6 April 2009 Mw 6.3 L’Aquila earthquake, central Italy.
Title of journal: Journal of Geophysical Research -Solid Earth
Series/Report no.: /115(2010)
Publisher: AGU
Issue Date: 2010
Keywords: L'Aquila 2009 earthquake
fault kinematics and reactivation
Abstract: On April 6 2009, a Mw=6.3 earthquake occurred in the central Apennines (Italy) damaging L’Aquila city and the surrounding country. We relocate the October 2008-April 6 2009 foreshocks and about 2000 aftershocks occurred between April 6 and April 30 2009, by applying a double-difference technique and determine the stress field from focal mechanisms. The events concentrate in the upper 15 km of the crust. Three main NW-SE to NNW-SSE striking, 30°-45° and 80°-90° dipping faults activate during the seismic sequence. Among these, a normal fault and a thrust were re-activated with dip-slip movements in response to NE-SW extension. The structural maturity of the seismogenic fault system is lower than that displayed by other systems in southern Apennines, because of the lower strain rate of the central sector of the chain with respect to the southern one. VP/VS increases progressively from October 2008 to the April 6 2009 mainshock occurrence along a NW-SE strike due to an increment in pore fluid pressure along the fault planes. Pore pressure diffusion controls the space-time evolution of aftershocks. A hydraulic diffusivity of 80 m2/s and a seismogenic permeability of about 10-12 m2 suggest the involvement of gas-rich (CO2) fluids within a highly fractured medium. Suprahydrostatic, high fluid pressure (about 200 MPa at 10 km of depth) within overpressurized traps, bounded by pre-existing structural and/or lithological discontinuities at the lower-upper crust boundary, are required to activate the April 2009 sequence. Traps are the storage zone of CO2-rich fluids uprising from the underlying, about 20 km deep, metasomatized mantle wedge. These traps easily occur in extensional regimes like in the axial sector of Apennines, but are difficult to form in strike-slip regimes, where sub-vertical faults may cross the entire crust. In the Apennines, fluids may activate faults responsible for earthquakes up to Mw=5-6. Deep fluids more than tectonic stress may control the seismotectogenesis of accretionary wedges.
Appears in Collections:04.06.99. General or miscellaneous
Papers Published / Papers in press

Files in This Item:

File SizeFormatVisibility
687804_2_merged_1264678443.pdf3.48 MBAdobe PDFView/Open

This item is licensed under a Creative Commons License
Creative Commons


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.


Share this record
Del.icio.us

Citeulike

Connotea

Facebook

Stumble it!

reddit


 

Valid XHTML 1.0! ICT Support, development & maintenance are provided by CINECA. Powered on DSpace Software. CINECA