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| Titel |
Experimental Comparison of Load-Strengthening and Load-Weakening Behaviour Leading to Fault Reshear |
| VerfasserIn |
Tom Mitchell, Richard Sibson, Jörg Renner |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250045049
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| Zusammenfassung |
| In this study, we assess the loading of faults to failure under different stress regimes in a
triaxial deformation apparatus, both in dry and saturated conditions. We explore
experimentally the reshear of an existing fault at particular values of (Ïă1 – Ïă3) and Ïă3’ for
contrasting loading systems - load-strengthening (equivalent to a thrust fault) with Ïă1’
increasing at constant Ïă3’, versus load-weakening (equivalent to a normal fault) with
reducing Ïă3’ under constant Ïă1’.  Prefailure and postfailure behaviour is compared in terms
of damage zone development via monitoring variations in ultrasonic velocity and acoustic
emission behaviour. In addition, we explore reshear conditions under an initial condition
of (Ïă1‘ = Ïă3’), then inducing reshear on the existing fault first by increasing Ïă1’
(load-strengthening), then by decreasing Ïă3’ (load-weakening), again comparing relative
damage zone development and acoustic emission levels. Experiments are conducted on
sawcut granite samples with fault angles at a variety of orientations relative to Ïă1, ranging
from an optimal orientation for reactivation to orientation for frictional lock-up. |
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