A chemical kinetic approach to estimate dynamic shear stress during the 1999 Taiwan Chi‐Chi earthquake

Abstract

Estimation of the dynamic shear stress on a fault during an earthquake is important for understanding the earthquake itself. Using a chemical kinetic approach, we examined the thermal decomposition of carbonate minerals to estimate the shear stress on the Taiwan Chelungpu fault, which slipped during the 1999 Chi‐Chi earthquake. The reaction rate of the decomposition was related to temperature by using the Arrhenius equation, and the chemical kinetics, taking into account the temperature change over time caused by frictional heating and heat conduction, was solved by the finite difference method. The dynamic shear stress during the Chi‐Chi earthquake was deduced to be 1.31 MPa, and the frictional coefficient to be 0.04–0.05. This estimated value agrees with the hypothesis that friction along the Chelungpu fault was low.