A model is proposed to explain the spatial distribution of foreshocks of the June 17-th 2000, Ms=6.6 earthquake in the South Iceland Seismic Zone (SISZ) and the high stress drop of the mainshock. Fluids of magmatic origin, ascending at near-lithostatic pressure through a low permeability layer perturb the regional stress field, inhibiting fluid flow laterally, where a high strength asperity is left. The asperity is modeled as elastic, embedded within a medium with low effective rigidity. Regional stresses due to tectonic motions are perturbed by the presence of the asperity, enhancing the production of hydrofractures and foreshocks in the NW and SE quadrants and increasing considerably the shear stress within the asperity, leading to the NS striking mainshock.
BONAFEDE M., FERRARI C., MACCAFERRI F., STEFANSSON R. (2007). On the preparatory processes of the M6.6 earthquake of June 17-th, 2000 in Iceland. GEOPHYSICAL RESEARCH LETTERS, 34, L24305,-doi:10.1029... [10.1029/2007GL031391].
On the preparatory processes of the M6.6 earthquake of June 17-th, 2000 in Iceland
BONAFEDE, MAURIZIO;FERRARI, CLAUDIO;MACCAFERRI, FRANCESCO;
2007
Abstract
A model is proposed to explain the spatial distribution of foreshocks of the June 17-th 2000, Ms=6.6 earthquake in the South Iceland Seismic Zone (SISZ) and the high stress drop of the mainshock. Fluids of magmatic origin, ascending at near-lithostatic pressure through a low permeability layer perturb the regional stress field, inhibiting fluid flow laterally, where a high strength asperity is left. The asperity is modeled as elastic, embedded within a medium with low effective rigidity. Regional stresses due to tectonic motions are perturbed by the presence of the asperity, enhancing the production of hydrofractures and foreshocks in the NW and SE quadrants and increasing considerably the shear stress within the asperity, leading to the NS striking mainshock.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
