A new ESR signal (R signal) in quartz grains taken from fault gauges: its properties and significance for ESR fault dating

We have detected a new ESR signal, overlapping the E1′ signal, in quartz grains taken from thin gouge layers of active petrological faults. This newly observed signal (R signal) is better detected at high microwave powers. The intensity of the R signal increases by exposing to artificial gamma rays, whereas the E1′ signal intensity decreases. We consider that the equivalent dose for the R signal reflects the age of the most recent faulting, and that the equivalent doses for ‘the E1′ signal’ in the literature should be re-examined. Several properties of the R signal are presented along with t he equivalent dose for the R signal of quartz in fault gouges.