Figure 10

Schematic illustration of how a profile of pore pressure and least principal stress measurements made through cemented casing can be used to distinguish between the two hypotheses illustrated in Figure 2. If the localized high pore pressure hypothesis is correct, both the pore pressure and least principal stress should be higher in the fault zone than in the surrounding crust. The inset figure represents calculations of Rice (1992) that indicate a ~ 10 MPa increase in pore pressure in the fault zone.