Energy taken up by co‐seismic chemical reactions during a large earthquake: An example from the 1999 Taiwan Chi‐Chi earthquake

Frictional heat in a fault zone during earthquake slip transiently induces chemical reactions that may use energy released during the earthquake. We estimated the energy used by such reactions ( E C ) by a numerical analysis incorporating frictional heat, thermal diffusion, chemical kinetics, and energy conservation, and found that E C has an auto‐feedback effect that inhibits temperature rise in fault zone. During the 1999 Taiwan Chi‐Chi earthquake, estimated E C was 0.43 MJ/m 2 , corresponding to 0.79% of the frictional heat generated. This low percentage probably reflects the low initial concentrations of reactive materials. However, in the case of a fault with abundant reactive materials, E C could reach >50% of the frictional heat and the auto‐feedback effect could be large. At this case E C is a nonnegligible component on earthquake energy budget and can affect fault mechanics.