From field geology to earthquake simulation: a new state-of-the-art tool to investigate rock friction during the seismic cycle (SHIVA)

Toro, Giulio Di; Niemeijer, A. R.; Tripoli, Antonino; Nielsen, S. B.; Felice, Fabio Di; Scarlato, Piergiorgio; Spada, Giuseppe; Alessandroni, Roberto; Romeo, G.; Stefano, Giuseppe Di; Smith, Steven A.; Spagnuolo, Elena; Mariano, S.

doi:10.1007/s12210-010-0097-x

“…To understand the origin of the mirror-like slip surfaces along the Foiana Line, low-to highvelocity experiments were performed using a rotary-shear friction apparatus [Slow to High Velocity Apparatus (SHIVA) at the Istituto Nazionale di Geofi sica e Vulcanologia in Rome; Di Toro et al, 2010] at conditions approaching those estimated for the Foiana Line. Tests were conducted on 3-mm-thick layers of dolostone gouge (100% dolomite, grain size <250 µm) collected from the fault outcrops and mounted in a gouge sample holder (Smith et al, 2013).…”

Section: Methodsmentioning

confidence: 99%

Mirror-like faults and power dissipation during earthquakes

Fondriest

¹

,

Smith

²

,

Candela

³

et al. 2013

Geology

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Earthquakes occur along faults in response to plate tectonic movements, but paradoxically, are not widely recognized in the geological record, severely limiting our knowledge of earthquake physics and hampering accurate assessments of seismic hazard. Light-reflective (so-called mirror like) fault surfaces are widely observed geological features, especially in carbonate-bearing rocks of the shallow crust. Here we report on the occurrence of mirrorlike fault surfaces cutting dolostone gouges in the Italian Alps. Using friction experiments, we demonstrate that the mirror-like surfaces develop only at seismic slip rates (similar to 1 m/s) and for applied normal stresses and sliding displacements consistent with those estimated on the natural faults. Under these experimental conditions, the frictional power density dissipated in the samples is comparable to that estimated for natural earthquakes (1-10 MW/m(2)). Our results indicate that mirror-like surfaces in dolostone gouges are a signature of seismic faulting, and can be used to estimate power dissipation during ancient earthquake ruptures

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“…Seven experiments were performed at room temperature and room humidity using the slow-to high-velocity rotary-shear friction apparatus (SHIVA) at the high-pressure-high-temperature laboratories of the Istituto Nazionale di Geofi sica e Vulcanologia (INGV, Rome, Italy) (Di Toro et al, 2010). The black gouges were fi rst gently crushed and sieved to a grain size of <250 µm.…”

Section: Experimental Methodsmentioning

confidence: 99%

Gouge graphitization and dynamic fault weakening during the 2008 Mw 7.9 Wenchuan earthquake

Kuo¹,

Li²,

Smith³

et al. 2013

Geology

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Earthquakes occur along faults in response to plate tectonic movements, but paradoxically, are not widely recognized in the geological record, severely limiting our knowledge of earthquake physics and hampering accurate assessments of seismic hazard. Light-reflective (so-called mirror like) fault surfaces are widely observed geological features, especially in carbonate-bearing rocks of the shallow crust. Here we report on the occurrence of mirrorlike fault surfaces cutting dolostone gouges in the Italian Alps. Using friction experiments, we demonstrate that the mirror-like surfaces develop only at seismic slip rates (similar to 1 m/s) and for applied normal stresses and sliding displacements consistent with those estimated on the natural faults. Under these experimental conditions, the frictional power density dissipated in the samples is comparable to that estimated for natural earthquakes (1-10 MW/m(2)). Our results indicate that mirror-like surfaces in dolostone gouges are a signature of seismic faulting, and can be used to estimate power dissipation during ancient earthquake ruptures

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“…The experiments discussed here were performed using SHIVA (Slow to High Velocity Apparatus, [43] HP-HT laboratory of the INGV of Rome, Italy), a high velocity rotary shear machine designed to simulate natural seismic deformation conditions in the uppermost Earth' crust (e.g., slip rates of 1 m/s and normal stress of 10 MPa). We selected Carrara marble (s769, 99% calcite) as representative of the 20% of sedimentary carbonate-bearing rocks where intra-plate earthquakes occur.…”

Section: High Speed Friction Experiments In Rock Materialsmentioning

confidence: 99%

Dislocation Motion and the Microphysics of Flash Heating and Weakening of Faults during Earthquakes

Spagnuolo

¹

,

Plümper

²

,

Violay

³

et al. 2016

Self Cite

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Abstract:Earthquakes are the result of slip along faults and are due to the decrease of rock frictional strength (dynamic weakening) with increasing slip and slip rate. Friction experiments simulating the abrupt accelerations (>>10 m/s 2 ), slip rates (~1 m/s), and normal stresses (>>10 MPa) expected at the passage of the earthquake rupture along the front of fault patches, measured large fault dynamic weakening for slip rates larger than a critical velocity of 0.01-0.1 m/s. The dynamic weakening corresponds to a decrease of the friction coefficient (defined as the ratio of shear stress vs. normal stress) up to 40%-50% after few millimetres of slip (flash weakening), almost independently of rock type. The microstructural evolution of the sliding interfaces with slip may yield hints on the microphysical processes responsible for flash weakening. At the microscopic scale, the frictional strength results from the interaction of micro-to nano-scale surface irregularities (asperities) which deform during fault sliding. During flash weakening, the visco-plastic and brittle work on the asperities results in abrupt frictional heating (flash heating) and grain size reduction associated with mechano-chemical reactions (e.g., decarbonation in CO 2 -bearing minerals such as calcite and dolomite; dehydration in water-bearing minerals such as clays, serpentine, etc.) and phase transitions (e.g., flash melting in silicate-bearing rocks). However, flash weakening is also associated with grain size reduction down to the nanoscale. Using focused ion beam scanning and transmission electron microscopy, we studied the micro-physical mechanisms associated with flash heating and nanograin formation in carbonate-bearing fault rocks. Experiments were conducted on pre-cut Carrara marble (99.9% calcite) cylinders using a rotary shear apparatus at conditions relevant to seismic rupture propagation. Flash heating and weakening in calcite-bearing rocks is associated with a shock-like stress release due to the migration of fast-moving dislocations and the conversion of their kinetic energy into heat. From a review of the current natural and experimental observations we speculate that this mechanism tested for calcite-bearing rocks, is a general mechanism operating during flash weakening (e.g., also precursory to flash melting in the case of silicate-bearing rocks) for all fault rock types undergoing fast slip acceleration due to the passage of the seismic rupture front.

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From field geology to earthquake simulation: a new state-of-the-art tool to investigate rock friction during the seismic cycle (SHIVA)

Cited by 81 publications

References 71 publications

Mirror-like faults and power dissipation during earthquakes

Mirror-like faults and power dissipation during earthquakes

Gouge graphitization and dynamic fault weakening during the 2008 Mw 7.9 Wenchuan earthquake

Dislocation Motion and the Microphysics of Flash Heating and Weakening of Faults during Earthquakes

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