The 8 June 2008 M(w) 6.4 Earthquake in Northwest Peloponnese, Western Greece: A Case of Fault Reactivation in an Overpressured Lower Crust?

NCUIR > College of Earth Sciences > Graduate Institute of Geophysics > journal & Dissertation > Item 987654321/50593

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/50593

Title:	The 8 June 2008 M(w) 6.4 Earthquake in Northwest Peloponnese, Western Greece: A Case of Fault Reactivation in an Overpressured Lower Crust?
Authors:	Konstantinou,KI;Evangelidis,CP;Melis,NS
Contributors:	地球物理研究所
Keywords:	HELLENIC SUBDUCTION;VELOCITY STRUCTURE;SEISMIC SEQUENCES;FOCAL MECHANISMS;MANTLE FLUIDS;STRESS-FIELD;CALIFORNIA;RUPTURE;ZONE;DEFORMATION
Date:	2011
Issue Date:	2012-03-27 17:37:28 (UTC+8)
Publisher:	國立中央大學
Abstract:	On 8 June 2008 a strong (M(w) 6.4) earthquake occurred in the area of northwest Peloponnese, western Greece. The event originated in the lower crust and was caused by the rupture of a previously unknown fault probably inherited from past tectonic phases. In this study we perform a stress inversion of all available focal mechanisms in this area in order to obtain an estimate of the regional stress field. It is shown that the maximum principal stress axis has an azimuth of N273 degrees E and forms an angle of 63 degrees with the fault's strike, which is well-constrained by seismological observations. This implies that the fault was severely misoriented with respect to the prevailing stress field assuming friction coefficients in the range 0.65-0.85. Calculation of pore-fluid factors for a variety of input parameters seems to confirm the presence of elevated fluid pressure near the hypocenter because they reach super-hydrostatic to lithostatic values (0.80-1.0). The source of these fluids is probably of deep origin and may have to do with upper mantle degassing. This suggestion is supported by the presence of mantle helium in spring waters close to the epicenter and by low Pn velocities consistent with partially molten mantle beneath northwest Peloponnese.
Relation:	BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
Appears in Collections:	[Graduate Institute of Geophysics] journal & Dissertation

Files in This Item:

File	Description	Size	Format
index.html		0Kb	HTML	712	View/Open

社群 sharing

Loading...