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| Titel |
Ultra-low friction during dynamic rupture in serpentinite |
| VerfasserIn |
Nicolas Brantut, Francois Passelegue, Damien Deldicque, Jean-Noel Rouzaud, Nadège Hilairet, Alexandre Schubnel |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250110667
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| Publikation (Nr.) |
 EGU/EGU2015-10693.pdf |
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| Zusammenfassung |
| The high-velocity frictional properties of serpentinites, which are key to understand the
dynamics of earthquake ruptures in subduction zones, are commonly expected to be governed
by the dehydration reaction of serpentine minerals which occurs upon heating. Here, we
performed stick-slip experiments which show that serpentinite dramatically weakens during
fast slip due to amorphisation and potentially melting of serpentine minerals at microscale
asperity contacts, in addition to water devolatilisation off the slip plane. The devolatilisation
is very localised near the slip plane, and likely provides an efficient thermal buffer which
limits the extension of the slip zone. The devolatilisation and amorphisation mechanisms are
very efficient dynamic weakening mechanisms, as demonstrated by the occurrence of total
stress drops (up to 180 megapascals (MPa)) over very short timescales (less than 20
microseconds) and large amplitude elastic wave radiation during the dynamic slip
events. Such a rapid weakening of serpentinites at high-velocity could be a key
process facilitating the propagation of intermediate-depth subduction earthquakes. |
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