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Pore Pressure Drop During Dynamic Rupture and Conditions for Dilatancy Hardening
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SYSNO ASEP 0573882 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Pore Pressure Drop During Dynamic Rupture and Conditions for Dilatancy Hardening Author(s) Pařez, Stanislav (UCHP-M) RID, ORCID, SAI
Kozakovič, M. (CZ)
Havlica, Jaromír (UCHP-M) RID, ORCID, SAIArticle number e2023JB026396 Source Title Journal of Geophysical Research-Solid Earth. - : Wiley - ISSN 2169-9313
Roč. 128, č. 7 (2023)Number of pages 30 s. Language eng - English Country US - United States Keywords dilatancy ; pore fluid pressure ; fault mechanics OECD category Geology R&D Projects GJ19-21114Y GA ČR - Czech Science Foundation (CSF) Method of publishing Open access Institutional support UCHP-M - RVO:67985858 UT WOS 001042049100001 EID SCOPUS 85164031833 DOI 10.1029/2023JB026396 Annotation Pore pressure drop brought about by fault dilatancy during accelerating slip may suppress nucleation of earthquakes. Yet, direct measurements of pore pressure during dynamic slip are challenging to produce. We present results of a physics-based model simulating onset of slip in saturated granular layers coupled to a constant fluid pressure reservoir. Grain rearrangements required for slip to commence induce incipient rapid dilatation during which the maximum pore pressure drop is generated. We find that up to a critical slip rate the pore pressure drop is consistent with a prediction derived for an incompressible fluid flow. In this drained regime, excess pore pressure is efficiently relaxed and has little effect on slip stability. Above the critical slip rate, marking the onset of undrained conditions, the pore pressure drop decays slowly, inhibits dilatation rate, and significantly increases strength of the layer, stabilizing the rupture growth. The magnitude of the pore pressure drop increases monotonically with the drainage number given as the ratio of the dilatation rate to a characteristic fluid infiltration rate. The pore pressure drop in the undrained regime also depends on a second non-dimensional parameter, urn:x-wiley:21699313:media:jgrb56355:jgrb56355-math-0001, where β is storage capacity, and urn:x-wiley:21699313:media:jgrb56355:jgrb56355-math-0002 is the effective normal stress. Low values of this parameter enhance localization of strain near the drained boundaries of the layer, promoting fluid flow into the layer. Our results can be used to better constrain drainage conditions associated with changes in slip rate, the magnitude of the generated pore pressure and the corresponding fault strengthening. Workplace Institute of Chemical Process Fundamentals Contact Eva Jirsová, jirsova@icpf.cas.cz, Tel.: 220 390 227 Year of Publishing 2024 Electronic address https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2023JB026396?src=getftr
Number of the records: 1