Sa. Shapiro et al., ESTIMATING THE CRUST PERMEABILITY FROM FLUID-INJECTION-INDUCED SEISMIC EMISSION AT THE KTB SITE, Geophysical journal international, 131(2), 1997, pp. 15-18
During the hydraulic-fracturing experiment in the German Continental D
eep Drilling Borehole (KTB) in December 1994, microseismic activity wa
s induced. Here we develop a technique for estimating permeability usi
ng the spatio-temporal distribution of the fluid-injection-induced sei
smic emission. The values we have obtained for the KTB experiment (0.2
5x10(-16) to 1.0x10(-16) m(2)) are in a very good agreement with the p
revious hydraulic-type permeability estimates from KTB deep-observator
y studies. In addition, our estimates of the hydraulic diffusivity sup
port the previously calculated value for the upper crust, which is of
the order of 1 m(2) s(-1). However, this estimate now relates to the d
epth range 7.5-9 km.