“Tectonophysics,” v. 424, p. 109-118.

Kieran O’Hara and his co-authors investigate thermal pressurization effects in an experimental fault zone and show how frictional heat affects fault zone liquids and how the outcome reduces fault strength, thereby increasing the magnitude of an earthquake. The experiments were carried out at the University of Kyoto in the summer of 2004 using a high velocity friction machine. Instead of using rock, the researchers used coal because of its high volatility during frictional heating.

The results featured a feedback mechanism in which the frictional heat pressurized the fault zone liquids and therefore weakened the fault. In the article, O’Hara and his associates discuss the necessity for duplicating the experiment with rocks that commonly occur on active faults. These are the first experiments to demonstrate the thermal pressurization effect during frictional heating on a fault zone.

Kieran O’Hara is an associate professor in the Department of Earth and Environmental Sciences at the University of Kentucky. His areas of research include frictional heating on active and ancient faults and chemical changes in deep crustal shear zones. The native of Ireland earned his master’s (1982) and doctorate (1985) degrees from Brown University.