  The efficiency of thermal pressurisation as a dynamic weakening mechanism
relies on the thermal and hydraulic properties of the rocks forming the fault
core. Here, we assess the effectiveness of thermal pressurisation by comparing
predictions of temperature rise to field estimates based on
pseudotachylyte-bearing rocks. We measure hydraulic and transport properties of
a suite of fault rocks (a healed cataclasite, an unhealed breccia and the
intact parent rock) from the pseudotachylyte-bearing Gole Larghe fault in the
Adamello batholith (Italy), and use them as inputs in numerical simulations of
thermal pressurisation. We find that the melting temperature can be reached
only if damaged, unhealed rock properties are used. A tenfold increase in
permeability, or a fourfold increase in pore compressibility of the intact rock
is required to achieve melting. Our results emphasise the importance of damage
processes that strongly modify fault rock properties and dynamic weakening
processes during earthquake propagation.
