Richard Sibson talks about recognizing and mapping the different components of the Outer Hebrides thrust zone, some with pseudotachylites arising from friction melting during seismic slip. The scarcity of this material around other major fault zones (e.g., the Moine Thrust) led him to postulate inhibition of melting by transitory increases in pore fluid pressure during seismic slip in fluid-saturated fault zones. Recorded: October 29, 2013