Evolution of Off-Fault Deformation along Analog Strike-Slip Faults

Hatem, Alexandra E

Publication:
Evolution of Off-Fault Deformation along Analog Strike-Slip Faults

dc.contributor.advisor	Michele L Cooke
dc.contributor.author	Hatem, Alexandra E
dc.contributor.department	University of Massachusetts Amherst
dc.contributor.department	Geosciences
dc.date	2024-03-28T19:28:45.000
dc.date.accessioned	2024-04-26T18:36:08Z
dc.date.available	2024-04-26T18:36:08Z
dc.date.submitted	September
dc.date.submitted	2014
dc.description.abstract	Strike-slip faults evolve to accommodate more fault slip, resulting in less off-fault deformation. In analog experiments, the measured fault slip to off-fault deformation ratios are similar to those measured in crustal strike-slip systems, such as the San Andreas fault system. Established planar faults have the largest fault slip to off-fault deformation ratio of ~0.98. In systems without a pre-existing fault surface, crustal thickness and basal detachment conditions affect shear zone width and roughness. However, once the applied plate displacement is 1-2 times the crustal thickness, partitioning of deformation between fault slip and off-fault distributed shear is >0.90, regardless of the basal boundary conditions. In addition, at any moment during the evolution of the analog fault system, the ratio of fault slip to off-fault deformation is larger than the cumulative ratio. We also find that the upward and lateral propagation of faults as an active shear zone developing early in the experiments has greater impact on the system’s strike-slip efficiency than later interaction between non-collinear fault segments. For bends with stepover distance of twice the crustal thickness, the fault slip to off-fault deformation ratio increases up to ~0.80-0.90, after applied plate displacement exceeds twice the crustal thickness. Propagation of new oblique-slip faults around sharp restraining bends reduces the overall off-fault deformation within the fault system. In contrast, fault segments within gentle restraining bends continue to slip and the propagation of new oblique-slip faults have less effect on the system’s efficiency than for sharp restraining bends.
dc.description.degree	Master of Science (M.S.)
dc.identifier.doi	https://doi.org/10.7275/5972378
dc.identifier.orcid	N/A
dc.identifier.uri	https://hdl.handle.net/20.500.14394/33965
dc.relation.url	https://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1101&context=masters_theses_2&unstamped=1
dc.source.status	published
dc.subject	analog modeling
dc.subject	structural geology
dc.subject	fault initiation
dc.subject	restraining bends
dc.subject	strike-slip faults
dc.subject	Geology
dc.title	Evolution of Off-Fault Deformation along Analog Strike-Slip Faults
dc.type	openaccess
dc.type	article
dc.type	thesis
digcom.contributor.author	isAuthorOfPublication\|email:ahatem@cns.umass.edu\|institution:University of Massachusetts Amherst\|Hatem, Alexandra E
digcom.identifier	masters_theses_2/90
digcom.identifier.contextkey	5972378
digcom.identifier.submissionpath	masters_theses_2/90
dspace.entity.type	Publication