Co-seismic boiling cannot seal faults
Abstract
Co-seismic boiling (alternatively "decompression boiling" or "flash vaporization") and accompanying cementation is often invoked as a mechanism for facilitating fault-zone sealing in the seismic cycle. In this talk, I will examine the validity of this mechanism. I argue, based on simple physical calculations, that co-seismic boiling is a self-limited process following earthquake rupture and is not capable of facilitating significant sealing. More specifically, these calculations, which are based on the ideal gas law, demonstrate that the volume of water that can undergo co-seismic boiling is less than 6% of the dilatational volume formed during fault slip. Additional calculations show that the amount of quartz or other cements that can precipitate from these fluid volumes leads to sub-micron levels of growth on fracture walls, which are likely of negligible impact on fault permeability. These new constraints have fundamental implications for our understanding of the "fault-valve" model, where relatively rapid mineral growth rates are required to facilitate sealing within a time frame that is compatible with the recurrence interval of large earthquake ruptures.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.T11G0235W
- Keywords:
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- 8010 Fractures and faults;
- STRUCTURAL GEOLOGYDE: 8045 Role of fluids;
- STRUCTURAL GEOLOGYDE: 8118 Dynamics and mechanics of faulting;
- TECTONOPHYSICSDE: 8163 Rheology and friction of fault zones;
- TECTONOPHYSICS