2:00 PM - 2:15 PM
[SGL35-02] A new method to estimate fault activity based on the fraction of saturation of quartz luminescence and ESR signals in fault rocks
Keywords:luminescence, electron spin resonance, thermochronology, fault activity
Active faults in Japan are categorised according to their slip rates into three classes (A, B, and C-classes) (Matsuda, 1975). An A-class fault experiences more frequent and larger-energy earthquakes than B- and C-class faults, contributing to a greater removal of trapped charge in quartz by frictional heating. Therefore, our working hypothesis is that the fraction of trapped charge saturation of A-class faults should be significantly lower than that of B-class faults, which themselves are lower than those of C-class; i.e. the fraction of trapped charge saturation is a function of the fault activity. By inverting the fractions of saturation using their corresponding trap kinetic parameters, one can estimate one of the following: the frequency, the temperature, or the duration of the resetting events (earthquakes), if the other two parameters are independently constrained.
In this presentation, we share our preliminary results from the Atotsugawa Fault, central Japan (including experimental data, modelling and inversion), and discuss the method’s potential contribution to understanding fault mechanics (flash heating, in particular) and to estimate fault activity.
Matsuda, T., 1975, Magnitude and recurrence interval of earthquakes from a fault. Zisin (2nd ser.), 28, 3, 269-283.
Research Group for Active Faults of Japan, 1991. Active Faults in Japan. University of Tokyo Press, Tokyo.