Premium
In‐situ stress fields and focal mechanism solutions in central France
Author(s) -
Scotti Oona,
Cornet François H.
Publication year - 1994
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 - 10.1029/94gl02634
Subject(s) - focal mechanism , stress field , extrapolation , geology , homogeneous , stress (linguistics) , geodesy , amplitude , seismology , field (mathematics) , principal stress , geophysics , tectonics , physics , optics , statistical physics , mathematics , paleontology , statistics , linguistics , philosophy , finite element method , pure mathematics , shear (geology) , thermodynamics
Focal mechanisms of 31 Central France earthquakes (m b = 2.9‐4.4) were evaluated to determine if slip is compatible with stress field determinations conducted at four nearby sites. The coherent picture that results indicates that the regional stress fields can be inferred by linear extrapolation of in‐situ measurements performed between 400–1000 m depths. Furthermore, the results show that in spite of rather constant principal stress directions from one site to the next (100 km apart), principal stress amplitudes vary significantly. For the domain investigated (200×200 km²), the size of the homogeneous stress field regions appears to be fairly small (about 100×100 km²). In addition, within these regions, important local stress perturbations as identified by extremely inconsistent focal mechanisms, are present. Thus only by integrating different data types is it possible to map properly the regional stress field. This mapping provides means to identify the homogeneous regions as well as to highlight zones of local stress perturbations, most likely indicative of active faulting.