2:30 PM - 2:52 PM
[SSS15-21] Thermal maturity of carbonaceous materials as a new indicator for frictional heat recorded in fault zones during earthquakes
Keywords:Earthquake, Frictional heat, Carbonaceous material
Carbonaceous material (CM), which changes its organochemical characteristics irreversibly with increasing ambient temperature, has been received a marked attention as a new temperature proxy for fault zones since more than 10 years ago. The amount of frictional heat recorded in CM was traditionally investigated by vitrinite reflectance measurement, and recently by IR/Raman spectroscopies, CHO elemental analyses, and biomarker indexes. On the basis of temperatures estimated from these indicators, some studies conducted numerical simulations to infer slip behaviors during earthquakes. However, thermal maturation reaction of CM contains some uncertainties caused from changes in reactivity owing to coseismic shearing, kinetic effects of heating rate, and cumulative effects by earthquake repeating. Understanding how much these effects could affect on CM thermometer is necessary for establishing more accurate temperature indicator. In this presentation, we track the history of CM as a useful thermometer for fault rocks and introduce our recent works investigating effects of coseismic shearing and heating rate on CM thermometer.