Geological controls on fault relay zone scaling

Long, J.J.; Imber, J.

doi:10.1016/j.jsg.2011.09.011

Geological controls on fault relay zone scaling

Long, J.J.; Imber, J.

Authors

J.J. Long

J. Imber

Abstract

The overlap and separation distances of relay zones follow a power-law scaling relationship over nearly 8 orders of magnitude. Approximately one order of magnitude scatter in both separation and overlap exists at all scales. The strong power-law relationship (R2 = 0.98) suggests that the primary control on relay aspect ratio (overlap/separation) is a scale-invariant process, such as the stress interaction between the overlapping fault tips as suggested by previous authors. Within the compiled global dataset host rock lithology does not appear to be a first-order control. Much of the observed scatter can be attributed to the spread of measurements recorded from individual relay zones, which relates to the evolving three-dimensional geometry of the relay zone as displacements on the bounding faults increase. Relay ramps exposed at two localities where the faults cut layered sedimentary sequences display mean aspect ratios of 8.20 and 8.64 respectively, more than twice the global mean (4.2). Such high aspect ratios can be attributed to the relay-bounding faults having initially been confined within competent layers, facilitating the development of large overlap lengths. The presence of pre-existing structures (veins) at fault tips may also enhance fault propagation, giving rise to increased overlap lengths.

Citation

Long, J., & Imber, J. (2011). Geological controls on fault relay zone scaling. Journal of Structural Geology, 33(12), 1790-1800. https://doi.org/10.1016/j.jsg.2011.09.011

Journal Article Type	Article
Publication Date	Dec 1, 2011
Deposit Date	Jan 16, 2012
Publicly Available Date	Feb 2, 2012
Journal	Journal of Structural Geology
Print ISSN	0191-8141
Publisher	Elsevier
Peer Reviewed	Peer Reviewed
Volume	33
Issue	12
Pages	1790-1800
DOI	https://doi.org/10.1016/j.jsg.2011.09.011
Keywords	Relay zone scaling, Mechanical stratigraphy, Fault interaction, Aspect ratio, Stress field.

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Copyright Statement
NOTICE: this is the author’s version of a work that was accepted for publication in Journal of structural geology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of structural geology, Volume 33, Issue 12, December 2011, 10.1016/j.jsg.2011.09.011.