Publication Date:
2021-12-16
Description:
We performed 31 friction experiments on glassy basalts (GB) and glass-free basalts (GFB) at slip rates up to 6.5 m s−1 and normal stress up to 40 MPa (seismic conditions). Frictional weakening was associated to bulk frictional melting and lubrication. The weakening distance (Dw) was about 3 times shorter in GB than in GFB, but the steady state friction was systematically higher in GB than in GFB. The shorter Dw in GB may be explained by the thermal softening occurring at the glass transition temperature (Tg ~500°C), which is lower than the bulk melting temperature (Tm ~1250°C) of GFB. Postexperiment microanalyses suggest that the larger crystal fraction measured in GB melts results in the higher steady state friction value compared to the GFB melts. The effect of interstitial glass is to facilitate frictional instability and rupture propagation in GB with respect to GFB.
Description:
Published
Description:
348-355
Description:
4T. Fisica dei terremoti e scenari cosismici
Description:
JCR Journal
Description:
embargoed_20160201
Keywords:
Earthquakes
;
Friction
;
Basalts
;
Interstitial glass
;
04. Solid Earth::04.01. Earth Interior::04.01.04. Mineral physics and properties of rocks
;
04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones
;
04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry
;
04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution
;
04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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