How faulting keeps the crust strong

Deep drilling and induced seismicity experiments at several locations world wide indicate that, in general, the brittle crust in intraplate regions is critically stressed, pore pressures are close to hydrostatic, and in situ b ulk permeability is similar to 10(-17) to 10(-16) m(2). This high permeabil ity, three or four orders of magnitude higher than that measured on core sa mples, appears to be maintained by critically stressed faults and greatly f acilitates fluid movement through the brittle crust. We demonstrate that su ch high permeabilities can maintain approximately hydrostatic fluid pressur es at depths comparable to the thickness of the seismogenic crust, This lea ds to the counterintuitive result that faulting keeps intraplate crust inhe rently strong by preventing pore pressures greater than hydrostatic from pe rsisting at depth.