scholarly journals Frictional strength of ground dolerite gouge at a wide range of slip rates

2016 ◽  
Vol 121 (4) ◽  
pp. 2961-2979 ◽  
Author(s):  
Jun-ichi Wada ◽  
Kyuichi Kanagawa ◽  
Hiroko Kitajima ◽  
Miki Takahashi ◽  
Atsuyuki Inoue ◽  
...  
Keyword(s):  
Slip Rates ◽  
Frictional Strength ◽  
Wide Range

scholarly journals Tire/Road Rolling Resistance Modeling: Discussing the Surface Macrotexture Effect

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 538
Author(s):  
Malal Kane ◽  
Ebrahim Riahi ◽  
Minh-Tan Do
Keyword(s):  
Slip Rate ◽  
Rolling Resistance ◽  
Friction Model ◽  
Slip Rates ◽  
Wide Range ◽  
Road Surfaces ◽  
Profile Depth ◽  
Experimental Rolling ◽  
Resistance Modeling ◽  
Pavement Friction

This paper deals with the modeling of rolling resistance and the analysis of the effect of pavement texture. The Rolling Resistance Model (RRM) is a simplification of the no-slip rate of the Dynamic Friction Model (DFM) based on modeling tire/road contact and is intended to predict the tire/pavement friction at all slip rates. The experimental validation of this approach was performed using a machine simulating tires rolling on road surfaces. The tested pavement surfaces have a wide range of textures from smooth to macro-micro-rough, thus covering all the surfaces likely to be encountered on the roads. A comparison between the experimental rolling resistances and those predicted by the model shows a good correlation, with an R2 exceeding 0.8. A good correlation between the MPD (mean profile depth) of the surfaces and the rolling resistance is also shown. It is also noticed that a random distribution and pointed shape of the summits may also be an inconvenience concerning rolling resistance, thus leading to the conclusion that beyond the macrotexture, the positivity of the texture should also be taken into account. A possible simplification of the model by neglecting the damping part in the constitutive model of the rubber is also noted.

Flash Heating Leads to Low Frictional Strength of Crustal Rocks at Earthquake Slip Rates

Science ◽  
2011 ◽  
Vol 334 (6053) ◽  
pp. 216-218 ◽  
Author(s):  
D. L. Goldsby ◽  
T. E. Tullis
Keyword(s):  
Slip Rates ◽  
Crustal Rocks ◽  
Frictional Strength

Spatio-temporal slip rate variability of the Doruneh fault (eastern Iran) from dense GNSS and SENTINEL data and a tectonic study

2021 ◽  
Author(s):  
Andrea Walpersdorf ◽  
Fatemeh Khorrami ◽  
Zahra Mousavi ◽  
Erwan Pathier ◽  
Farokh Tavakoli ◽  
...  
Keyword(s):  
Slip Rate ◽  
Tropospheric Delay ◽  
Great Length ◽  
Fault Activity ◽  
Fault Creep ◽  
Slip Rates ◽  
Long Wavelength ◽  
Eastern Iran ◽  
Wide Range

<p>The recent activity of the 600 km long E-W trending Doruneh fault in eastern Iran is attested by clear geomorphological features along its trace, while no instrumental earthquake can be related to this fault. The only two Mw7 events in this area took place on the Dasht-e Bayaz fault, south of Doruneh. The great length of the fault, the lack of the seismicity and the active regional N-S shortening induced by the Arabian-Eurasian convergence highlight the seismic potential of the Doruneh fault. However, until today, the short- and long-term slip rate estimates of the Doruneh fault remain controversial. Geomorphological offset dating indicates long-term slip rates between 2.5 mm/yr and 8.2 mm/yr. Preliminary GNSS measurements and local InSAR data reveal rates between 1 and 5 mm/yr.  This wide range of slip rate estimates suggests either temporal or spatial variability of the Doruneh fault activity.</p><p>To investigate the along-strike slip variability of the Doruneh fault, a dense GNSS survey including 18 sites has been conducted in 2012 and 2018. This network completes the 17 regional permanent GNSS stations. Combining campaign and permanent data, the horizontal GNSS velocity field constrains the slip velocity and its variability along the fault by complementary approaches, on profiles perpendicular to the fault, and by a rigid block model. Sinistral motion is maximal in the western part of the fault (1 to 4 mm/yr), and decreasing towards the east. A complementary InSAR velocity map based on Sentinel-1 images between 2014 and 2019 exploits two ascending tracks (A159 and A86) across the Doruneh fault. We followed the SBAS time series analysis approach and corrected the effects of annual loading cycles and tropospheric delay. Sand and unexpected large tropospheric effects prohibited correlation in some places, but a coherent mean velocity map in line of sight (LOS) direction to the satellites is obtained for most of our study area. This map shows no sharp variations along the fault trace that could indicate shallow fault creep. The clearest signals are zones of anthropogenic subsidence. Looking for a long-wavelength tectonic signal (less than 3 mm/yr spread over 100 km), we masked these areas of rapid and short-wavelength deformation. The resulting velocity maps for both tracks are projected on profiles perpendicular to the fault and indicate a long-wavelength signal across the Doruneh fault of less than 2 mm/yr in LOS direction. A systematic parameter search yields a first best fit on track A159 combining a horizontal slip rate of 3.25 mm/yr with a locking depth of 8 km in the western part of the fault. This approach will be pursued on track A86, covering the eastern part, after more thorough cleaning.</p><p>We finally compare the combined GNSS-InSAR present-day fault slip rates to new long-term slip rates from geomorphological offset dating, to evaluate the time variability of the Doruneh fault activity. Our multi-disciplinary study will enhance our understanding of the Doruneh fault mechanism and its role in the kinematics of the Arabia-Eurasia collision, and contribute to a better seismic hazard assessment in eastern Iran.</p>

scholarly journals Low frictional strength of quartz rocks at subseismic slip rates

2002 ◽  
Vol 29 (17) ◽  
pp. 25-1-25-4 ◽  
Author(s):  
David L. Goldsby ◽  
Terry E. Tullis
Keyword(s):  
Slip Rates ◽  
Frictional Strength

scholarly journals Crustal faults in the Chilean Andes: geological constraints and seismic potential

2018 ◽  
Vol 46 (1) ◽  
pp. 32 ◽  
Author(s):  
Isabel Santibáñez ◽  
José Cembrano ◽  
Tiaren García-Pérez ◽  
Carlos Costa ◽  
Gonzalo Yáñez ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Fault Reactivation ◽  
South American ◽  
Slip Rates ◽  
Seismic Potential ◽  
Recurrence Times ◽  
Wide Range ◽  
Chilean Andes

The Chilean Andes, as a characteristic tectonic and geomorphological region, is a perfect location to unravel the geologic nature of seismic hazards. The Chilean segment of the Nazca-South American subduction zone has experienced mega-earthquakes with Moment Magnitudes (Mw) >8.5 (e.g., Mw 9.5 Valdivia, 1960; Mw 8.8 Maule, 2010) and many large earthquakes with Mw >7.5, both with recurrence times of tens to hundreds of years. By contrast, crustal faults within the overriding South American plate commonly have longer recurrence times (thousands of years) and are known to produce earthquakes with maximum Mw of 7.0 to 7.5. Subduction-type earthquakes are considered the principal seismic hazard in Chile, with the potential to cause significant damage to its population and economy. However crustal (non-subduction) earthquakes can also cause great destruction at a local scale, because of their shallower hypocentral depth. Nevertheless, the nature, timing and slip rates of crustal seismic sources in the Chilean Andes remain poorly constrained. This work aims to address the seismic potential of the crustal faults in Chile, contributing to the estimation of key fault parameters for the seismic hazard assessment. We have examined the main parameters involved in the magnitude of an earthquake, including length, width and mean displacement of some case studies crustal faults and their morphotectonic settings, exposing the parametrical similarities in longitudinal domains (N-S stripes) and disparity from W to E, across latitudinal domains. The maximum hypocentral depths for crustal earthquakes vary across margin parallel tectonic domains aligned parallel, from 25-30 km in the outer forearc to 8-12 km in the volcanic arc, thus allowing for a first-order approach for seismic potential assessment. Current structural, paleoseismological and geodetic data, although sparse and limited, suggest that slip rates of Chilean crustal faults range from 0.2 mm/yr (in the forearc region) to up to 7.0 mm/yr (in the intra-arc region). The different tectonic modes for crustal fault reactivation and their wide range of slip rates complicates the estimation of seismic hazard. A rigorous seismic hazard assessment must therefore consider the different tectonic settings, timing and slip rates of Andean crustal faults. Understanding the nature of these faults will allow a better evaluation of the associated seismic hazard, and better constraints to be placed on their relationship with the subduction seismic cycle.

scholarly journals Molecular origin of sliding friction and flash heating in rock and heterogeneous materials

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Nariman Piroozan ◽  
Muhammad Sahimi
Keyword(s):  
Shear Stress ◽  
Sliding Friction ◽  
Frictional Stress ◽  
Strain Diagram ◽  
Stress Strain ◽  
Slip Rates ◽  
Contact Points ◽  
Wide Range ◽  
Molecular Scale ◽  
Interfacial Temperature

AbstractIt is generally believed that earthquakes occur when faults weaken with increasing slip rates. An important factor contributing to this phenomenon is the faults’ dynamic friction, which may be reduced during earthquakes with high slip rates, a process known as slip-rate weakening. It has been hypothesized that the weakening phenomenon during fault slip may be activated by thermal pressurization of pores’ fluid and flash heating, a microscopic phenomenon in which heat is generated at asperity contacts due to high shear slip rates. Due to low thermal conductivity of rock, the heat generated at the contact points or surfaces cannot diffuse fast enough, thus concentrating at the contacts, increasing the local contact temperature, and reducing its frictional shear strength. We report the results of what we believe to be the first molecular scale study of the decay of the interfacial friction force in rock, observed in experiemntal studies and attributed to flash heating. The magnitude of the reduction in the shear stress and the local friction coefficients have been computed over a wide range of shear velocities V. The molecular simulations indicate that as the interfacial temperature increases, bonds between the atoms begin to break, giving rise to molecular-scale fracture that eventually produces the flash heating effect. The frequency of flash heating events increases with increasing sliding velocity, leaving increasingly shorter times for the material to relax, hence contributing to the increased interfacial temperature. If the material is thin, the heat quickly diffuses away from the interface, resulting in sharp decrease in the temperature immediately after flash heating. The rate of heat transfer is reduced significantly with increasing thickness, keeping most of the heat close to the interface and producing weakened material. The weakening behavior is demonstrated by computing the stress–strain diagram. For small strain rates there the frictional stress is essentially independent of the materials’ thickness. As the strain rate increases, however, the dependence becomes stronger. Specifically, the stress–strain diagrams at lower velocities V manifest a pronounced strength decrease over small distances, whereas they exhibit progressive increase in the shear stress at higher V, which is reminiscent of a transition from ductile behavior at high velocities to brittle response at low velocities.

scholarly journals Frictional properties and microstructural evolution of dry and wet calcite-dolomite gouges

2020 ◽  
Author(s):  
Matteo Demurtas ◽  
Steven A.F. Smith ◽  
Elena Spagnuolo ◽  
Giulio Di Toro
Keyword(s):  
Microstructural Evolution ◽  
Shear Zones ◽  
Slip Zone ◽  
Cyclic Process ◽  
Experimental Conditions ◽  
Slip Rates ◽  
Bearing Faults ◽  
Seismic Slip ◽  
Wide Range ◽  
Dynamic Weakening

Abstract. Calcite and dolomite are the two most common minerals in carbonate-bearing faults and shear zones. Motivated by field examples from exhumed seismogenic faults in the Italian Central Apennines, we investigated the frictional and microstructural evolution of gouge mixtures consisting of 50 wt % calcite and 50 wt % dolomite using a rotary-shear apparatus. The gouges were sheared at a range of slip rates (30 µm s−1–1 m s−1), displacements (0.05–0.4 m), and normal loads (17.5–26 MPa), under both room humidity and water-dampened conditions. The frictional behaviour and microstructural evolution of the gouges were strongly influenced by the presence of water. At room humidity, slip strengthening behaviour was observed up to slip rates of 0.01 m s−1, which was associated with gouge dilation and the development of a 500–900 µm wide slip zone cut by Y-, R-, and R1-shear bands. Above a slip rate of 0.1 m s−1, dynamic weakening accompanied the development of a localised <100 µm thick principal slip zone preserving microstructural evidence for calcite recrystallization and dolomite decarbonation, while the bulk gouges developed a well-defined foliation consisting of organized domains of heavily fractured calcite and dolomite. In water-dampened conditions, evidence of gouge fluidization within a fine-grained principal slip zone was observed at a wide range of slip-rates from 30 µm s−1 to 0.1 m s−1, suggesting that caution is needed when relating fluidization textures to seismic slip in natural fault zones. Dynamic weakening in water-dampened conditions was observed at 1 m s−1, where the principal slip zone was characterised by patches of recrystallized calcite. However, local fragmentation and reworking of recrystallized calcite suggests a cyclic process involving formation and destruction of a heterogeneous slip zone. Our microstructural data show that development of a well-defined gouge foliation at these experimental conditions is limited to high-velocity (>0.1 m s−1) and room humidity, supporting the notion that some foliated gouges and cataclasites may form during seismic slip in natural carbonate-bearing faults.

scholarly journals Heating, weakening and shear localization in earthquake rupture

2017 ◽  
Vol 375 (2103) ◽  
pp. 20160015 ◽  
Author(s):  
James R. Rice
Keyword(s):  
Frictional Heating ◽  
Static Friction ◽  
Shear Zones ◽  
State University ◽  
Friction Coefficients ◽  
Slip Rates ◽  
Decomposition Reactions ◽  
Frictional Strength ◽  
Heating Effects ◽  
University College London

Field and borehole observations of active earthquake fault zones show that shear is often localized to principal deforming zones of order 0.1–10 mm width. This paper addresses how frictional heating in rapid slip weakens faults dramatically, relative to their static frictional strength, and promotes such intense localization. Pronounced weakening occurs even on dry rock-on-rock surfaces, due to flash heating effects, at slip rates above approximately 0.1 m s −1 (earthquake slip rates are typically of the order of 1 m s −1 ). But weakening in rapid shear is also predicted theoretically in thick fault gouge in the presence of fluids (whether native ground fluids or volatiles such as H 2 O or CO 2 released by thermal decomposition reactions), and the predicted localizations are compatible with such narrow shear zones as have been observed. The underlying concepts show how fault zone materials with high static friction coefficients, approximately 0.6–0.8, can undergo strongly localized shear at effective dynamic friction coefficients of the order of 0.1, thus fitting observational constraints, e.g. of earthquakes producing negligible surface heat outflow and, for shallow events, only rarely creating extensive melt. The results to be summarized include those of collaborative research published with Nicolas Brantut (University College London), Eric Dunham (Stanford University), Nadia Lapusta (Caltech), Hiroyuki Noda (JAMSTEC, Japan), John D. Platt (Carnegie Institution for Science, now at *gramLabs), Alan Rempel (Oregon State University) and John W. Rudnicki (Northwestern University). This article is part of the themed issue ‘Faulting, friction and weakening: from slow to fast motion’.

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