Long runout landslides: The role of frictional heating and hydraulic diffusivity

2007 ◽  
Vol 34 (7) ◽  
Author(s):  
L. Goren ◽  
E. Aharonov
Keyword(s):  
Frictional Heating ◽  
Long Runout ◽  
Hydraulic Diffusivity

scholarly journals Mode conversion of two-fluid shocks in a partially-ionised, isothermal, stratified atmosphere

2020 ◽  
Vol 637 ◽  
pp. A97
Author(s):  
B. Snow ◽  
A. Hillier
Keyword(s):  
Solar Atmosphere ◽  
Mode Conversion ◽  
Frictional Heating ◽  
Fast Mode ◽  
Compressional Waves ◽  
Pressure Scale ◽  
Velocity Drift ◽  
Two Fluid ◽  
Lower Solar Atmosphere

Context. The plasma of the lower solar atmosphere consists of mostly neutral particles, whereas the upper solar atmosphere is mostly made up of ionised particles and electrons. A shock that propagates upwards in the solar atmosphere therefore undergoes a transition where the dominant fluid is either neutral or ionised. An upwards propagating shock also passes a point where the sound and Alfvén speed are equal. At this point the energy of the acoustic shock can separated into fast and slow components. The way the energy is distributed between the two modes depends on the angle of magnetic field. Aims. We aim to investigate the separation of neutral and ionised species in a gravitationally stratified atmosphere. The role of two-fluid effects on the structure of the shocks post-mode-conversion and the frictional heating is quantified for different levels of collisional coupling. Methods. Two-fluid numerical simulations were performed using the (PIP) code of a wave steepening into a shock in an isothermal, partially-ionised atmosphere. The collisional coefficient was varied to investigate the regimes where the plasma and neutral species are weakly, strongly, and finitely coupled. Results. The propagation speeds of the compressional waves hosted by neutral and ionised species vary and, therefore, velocity drift between the two species is produced as the plasma attempts to propagate faster than the neutrals. This is most extreme for a fast-mode shock. We find that the collisional coefficient drastically impacts the features present in the system, specifically the mode conversion height, type of shocks present, and the finite shock widths created by the two-fluid effects. In the finitely-coupled regime, fast-mode shock widths can exceed the pressure scale height, which may lead to a new potential observable of two-fluid effects in the lower solar atmosphere.

The fate of garnet during (deep-seated) coseismic frictional heating: The role of thermal shock

Geology ◽  
2018 ◽  
Vol 46 (5) ◽  
pp. 471-474 ◽  
Author(s):  
Simone Papa ◽  
Giorgio Pennacchioni ◽  
Ross J. Angel ◽  
Manuele Faccenda
Keyword(s):  
Thermal Shock ◽  
Frictional Heating

scholarly journals The critical role of stratification in submarine channels: Implications for channelization and long runout of flows

2014 ◽  
Vol 119 (4) ◽  
pp. 2620-2641 ◽  
Author(s):  
R. M. Dorrell ◽  
S. E. Darby ◽  
J. Peakall ◽  
E. J. Sumner ◽  
D. R. Parsons ◽  
...  
Keyword(s):  
Critical Role ◽  
Long Runout ◽  
Submarine Channels

Role of hydraulic diffusivity in the decrease of weathering rates over time

2014 ◽  
Vol 512 ◽  
pp. 87-106 ◽  
Author(s):  
Fernando A.L. Pacheco ◽  
Cornelis H. Van der Weijden
Keyword(s):  
Hydraulic Diffusivity ◽  
Weathering Rates ◽  
Over Time

The Role of Calcining and Basal Fluidization in the Long Runout of Carbonate Slides: An Example from the Heart Mountain Slide Block, Wyoming and Montana, U.S.A.

2010 ◽  
Vol 118 (6) ◽  
pp. 577-599 ◽  
Author(s):  
Mark H. Anders ◽  
Bruce W. Fouke ◽  
Aubrey L. Zerkle ◽  
Enrico Tavarnelli ◽  
Walter Alvarez ◽  
...  
Keyword(s):  
Long Runout ◽  
Slide Block

Towards coupling fluid flow and rate-and-state friction in compacting visco-poro-elasto-plastic reservoirs

2020 ◽  
Author(s):  
Mohsen Goudarzi ◽  
Ylona van Dinther ◽  
Meng Li ◽  
René de Borst ◽  
Casper Pranger ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Induced Seismicity ◽  
Large Scale ◽  
Bulk Material ◽  
Frictional Heating ◽  
Fluid Pressure ◽  
Gas Production ◽  
Modeling Framework ◽  
Fully Coupled

<p>Induced seismicity as a result of natural gas production is a major challenge from both an industrial and a societal perspective. The compaction caused by gas production leads to changes of the effective pressure fields in the reservoir and stress redistributions occur particularly in the surrounding faults. In addition, the strong coupling between fluid flow and solid rock deformations and the role of fluid flow regarding the frictional properties of the faults necessitate a coupled and comprehensive modeling framework. A general and fully coupled thermo-hydro-mechanical finite difference formulation is developed herein and the results are verified against numerical benchmarks. A visco-elasto-plastic rheological behavior is assumed for the bulk material and a return-mapping algorithm is implemented for accurate simulation of the stress evolution. The geometrical features of the faults are incorporated into a regularized continuum framework, while the response of the fault zone is governed by a rate-and-state-dependent friction model. Numerical simulations are provided for large-scale problems and their efficiency is assured through the evaluation of the consistently linearized systems of equations along with the use of advanced numerical solvers and parallel computing. Although the proposed framework is a step towards the modeling of earthquake sequences for induced seismicity applications, the features of the numerical model are highlighted for other applications, including seismic events in subduction settings where the role of fluid flow inside the faults is considerable. Another application of the present, fully coupled hydro-thermo-mechanical formulation is the prediction of the fluid pressurization phenomena, where the frictional heating increases the magnitude of the pore fluid pressure inside the faults, and the resultant degradation of dynamic frictional strength is naturally captured. </p>

scholarly journals The impact of ground-ice thaw on landslide geomorphology and dynamics: two case studies in northern Iceland

Landslides ◽  
2021 ◽  
Author(s):  
Costanza Morino ◽  
Susan J. Conway ◽  
Matthew R. Balme ◽  
Jón Kristinn Helgason ◽  
Þorsteinn Sæmundsson ◽  
...  
Keyword(s):  
Slope Instability ◽  
Permafrost Degradation ◽  
Ground Ice ◽  
Long Runout ◽  
Loose Deposits ◽  
Landslide Event ◽  
Multiple Pulses ◽  
Steep Terrain ◽  
The Impact

AbstractAs consequence of ongoing climate change, permafrost degradation is thought to be increasingly affecting slope stability in periglacial environments. This is of growing concern in Iceland, where in the last decade, permafrost degradation has been identified among the triggering factors of landslides. The role of ground ice in conditioning the morphology and dynamics of landslides involving loose deposits is poorly understood. We show the geomorphological impact of the Móafellshyrna and Árnesfjall landslides that recently occurred in ice-cemented talus deposits in northern Iceland. Using field and aerial remote-sensing measurements of the morphological and morphometric characteristics of the landslides, we assess the influence of thawing ground ice on their propagation style and dynamics. The two mass movements are complex and are similar to rock- and debris-ice avalanches, changing trajectory and exhibiting evidence of transitioning their style of motion from a dry granular mass to a debris flow-like movement via multiple pulses. We infer that the thawing of ground ice together with the entrainment of saturated material provided the extra fluid causing this change in dynamics. The hazardous consequences of permafrost degradation will increasingly affect mountain regions in the future, and ground-ice thaw in steep terrain is a particularly hazardous phenomenon, as it may induce unexpected long-runout failures and can cause slope instability to continue even after the landslide event. Our study expands our knowledge of how landslides develop in unstable ice-cemented deposits and will aid assessment and mitigation of the hazard that they pose in Iceland and other mountainous periglacial areas.

The Role of Wear in the Initiation of Thermoelastic Instabilities of Rubbing Contact

1973 ◽  
Vol 95 (1) ◽  
pp. 71-75 ◽  
Author(s):  
T. A. Dow ◽  
R. A. Burton
Keyword(s):  
Thermal Expansion ◽  
Contact Pressure ◽  
Material Properties ◽  
Frictional Heating ◽  
Oscillatory Behavior ◽  
Two Dimensional ◽  
Infinite Body ◽  
Operating Variables ◽  
Uniform Value

Thermoelastic instability of rubbing contact results from the interaction of thermal expansion, frictional heating, and conduction of heat away from the contact zone. These interactions are modified by wear, which is shown to damp the growth of disturbances in contact pressure from a nominal uniform value. In some cases the presence of wear is found to give rise to oscillatory behavior where portions of the rubbing surfaces alternately rise and drop in temperature. These effects are analyzed for the case of a two-dimensional scraper or blade moving normal to its edge, which presses against the surface of a stationary semi-infinite body. The roles of material properties and operating variables are delineated in terms of dimensionless parameters appropriate to the system.

Transient Contact of Two Sliding Half-Planes With Wear

1987 ◽  
Vol 109 (4) ◽  
pp. 598-603 ◽  
Author(s):  
A. Azarkhin ◽  
J. R. Barber
Keyword(s):  
Contact Area ◽  
Material Removal ◽  
Frictional Heating ◽  
The Other ◽  
Cyclic Behavior ◽  
Governing Equations ◽  
Simple Geometry ◽  
Transient Contact ◽  
Two Bodies

We study the transient contact of two sliding bodies with a simple geometry. The model employs the Archard law of wear in which the rate of material removal is proportional to pressure and speed of sliding. The problem is formulated in terms of two governing equations with unknown pressure and heat flux at the interface. The equations are solved numerically, using appropriately chosen Green’s functions. We start with a single area of contact. As a result of frictional heating and thermal expansion, the contact area shrinks, which leads to further localization of pressure and temperature. The role of wear is twofold. By removing protruding portions of the two bodies, wear tends to smoothen out pressure and temperature. On the other hand, it causes the contact area to grow sufficiently large to become unstable and bifurcate. Areas carrying load are eventually removed by wear, and the contact moves elsewhere. The system develops a cyclic behavior in which contact and non-contact areas interchange.

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