scholarly journals Generation and propagation of stick-slip waves over a fault with rate-independent friction

2017 ◽  
Author(s):  
Iuliia Karachevtseva ◽  
Arcady V. Dyskin ◽  
Elena Pasternak
Keyword(s):  
P Wave ◽  
Elastic Rod ◽  
Stick Slip ◽  
One Dimensional ◽  
P Wave Velocity ◽  
Mass Spring Model ◽  
1D Model ◽  
Shear Spring ◽  
Mass Spring ◽  
Elastic Shear

Abstract. Stick-slip sliding is observed at various scales in fault sliding and the accompanied seismic events. It is conventionally assumed that the mechanism of stick-slip over geomaterials lies in the rate dependence of friction. However, the movement resembling the stick-slip could be associated with elastic oscillations of the rock around the fault, which occurs regardless of rate properties of the friction. In order to investigate this mechanism, two simple models were considered: a mass-spring model of Burridge and Knopoff type (BK model) and a one-dimensional (1D) model an infinite elastic rod driven by elastic shear spring. The results show that frictional sliding in the case of BK model demonstrates stick-slip-like motion even when the friction coefficient is constant. The 1D rod model predicts that any initial disturbance moves with a p-wave velocity, that is supersonically with the amplitude of disturbances decreasing with time. This effect might provide an explanation to the observed supersonic rupture propagation over faults.

scholarly journals Generation and propagation of stick-slip waves over a fault with rate-independent friction

2017 ◽  
Vol 24 (3) ◽  
pp. 343-349 ◽  
Author(s):  
Iuliia Karachevtseva ◽  
Arcady V. Dyskin ◽  
Elena Pasternak
Keyword(s):  
Wave Propagation ◽  
Frictional Coefficient ◽  
Propagation Model ◽  
P Wave ◽  
Spring Model ◽  
Elastic Rod ◽  
Stick Slip ◽  
Frictional Sliding ◽  
Mass Spring Model ◽  
Mass Spring

Abstract. Stick-slip sliding is observed at various scales in fault sliding and the accompanied seismic events. It is conventionally assumed that the mechanism of stick-slip over geo-materials lies in the rate dependence of friction. However, the movement resembling the stick-slip could be associated with elastic oscillations of the rock around the fault, which occurs irrespective of the rate properties of the friction. In order to investigate this mechanism, two simple models are considered in this paper: a mass-spring model of self-maintaining oscillations and a one-dimensional (1-D) model of wave propagation through an infinite elastic rod. The rod slides with friction over a stiff base. The sliding is resisted by elastic shear springs. The results show that the frictional sliding in the mass-spring model generates oscillations that resemble the stick-slip motion. Furthermore, it was observed that the stick-slip-like motion occurs even when the frictional coefficient is constant. The 1-D wave propagation model predicts that despite the presence of shear springs the frictional sliding waves move with the P wave velocity, denoting the wave as intersonic. It was also observed that the amplitude of sliding is decreased with time. This effect might provide an explanation to the observed intersonic rupture propagation over faults.

scholarly journals Investigations of Coal-Rock Parting-Coal Structure (CRCS) Slip and Instability by Excavation

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Guang-Jian Liu ◽  
Heng Zhang ◽  
Ya-Wei Zhu ◽  
Wen-Hao Cao ◽  
Xian-Jun Ji ◽  
...  
Keyword(s):  
Shear Failure ◽  
P Wave ◽  
Shear Behaviour ◽  
Failure Zone ◽  
Stick Slip ◽  
Coal Structure ◽  
P Wave Velocity ◽  
Splitting Failure ◽  
Shear And Tensile Cracks ◽  
Coal Rock

Slip and instability of coal-rock parting-coal structure (CRCS) subjected to excavation disturbance can easily induce coal-rock dynamic phenomena in deep coal mines. In this paper, the failure characteristics and influencing factors of CRCS slip and instability were investigated by theoretical analysis, numerical simulations, and field observations. The following main results are addressed: (1) the slip and instability of CRCS induced by excavation are due to stress release, and the damage of the rock parting is partitioned into three parts: shear failure zone, slipping zone, and splitting failure zone from inside to outside with slip; (2) the slip and instability process of CRCS is accompanied by initiation, expansion, and intersection of shear and tensile cracks. The development of the cracks is dominated by shear behaviour, while the tensile crack is the main factor affecting fracture and instability of CRCS; and (3) slip and instability of CRCS are characterized by stick-slip first and then stable slip, accompanied with high P-wave velocity and rockburst danger coefficient based on microseismic tomography.

scholarly journals Multiscale Mass-Spring Model for High-Rate Compression of Vertically Aligned Carbon Nanotube Foams

2014 ◽  
Vol 81 (12) ◽  
Author(s):  
Ramathasan Thevamaran ◽  
Fernando Fraternali ◽  
Chiara Daraio
Keyword(s):  
Carbon Nanotube ◽  
High Rate ◽  
Spring Model ◽  
One Dimensional ◽  
Mass Spring Model ◽  
Vertically Aligned ◽  
Mass Spring ◽  
Constitutive Parameters ◽  
Strain Responses

We present a one-dimensional, multiscale mass-spring model to describe the response of vertically aligned carbon nanotube (VACNT) foams subjected to uniaxial, high-rate compressive deformations. The model uses mesoscopic dissipative spring elements composed of a lower level chain of asymmetric, bilateral, bistable elastic springs to describe the experimentally observed deformation-dependent stress–strain responses. The model shows an excellent agreement with the experimental response of VACNT foams undergoing finite deformations and enables in situ identification of the constitutive parameters at the smaller lengthscales. We apply the model to two cases of VACNT foams impacted at 1.75 ms−1 and 4.44 ms−1 and describe their dynamic response.

Origin of the temporal evolution of elastic properties during laboratory seismic cycle.

2020 ◽  
Author(s):  
Federica Paglialunga ◽  
François X. Passelègue ◽  
Mateo Acosta ◽  
Marie Violay
Keyword(s):  
Elastic Properties ◽  
Wave Velocity ◽  
Confining Pressure ◽  
Seismic Damage ◽  
P Wave ◽  
Seismic Cycle ◽  
Stick Slip ◽  
P Wave Velocity ◽  
Confining Pressures ◽  
Thermally Treated

<p>Recent seismological observations highlighted that earthquakes are associated to drops in elastic properties around the fault zone (Brenguier et al., 2008). This drop is often attributed to co-seismic damage produced at the rupture tip, and can mostly be observed at shallow depths. However, it is known that in the upper crust, faults are surrounded by a zone of damage (Caine, Evans, & Forster, 1996). Because of this, the origin of the velocity change associated to earthquakes, as well as its recovery in the months following the rupture remains highly debated.</p><p>We conducted stick-slip experiments to explore the evolution of elastic waves velocities during the entire seismic cycle. The tests were run on saw-cut La Peyratte granite samples presenting different initial degrees of damage, obtained through thermal treatment. Three types of samples were studied: not thermally treated, thermally treated at 650 °C and thermally treated at 950 °C. Seismic events were induced in a triaxial configuration apparatus at different confining pressures ranging from 15 MPa to 120 MPa. Active acoustic measurements were carried through the whole duration of the tests and P-wave velocities were measured.</p><p> </p><p>The evolution of P-wave velocity follows the evolution of the shear stress acting on the fault, showing velocity drops during dynamic slip events. The evolution of the P-wave velocity drops with increasing confining pressure shows two different trends; the largest drops can be observed for low confining pressure (15 MPa) and decrease for intermediate confining pressures (up to 45 MPa), while for confining pressures of 60 MPa to 120 MPa, drops in velocity slightly increase with confining pressure.</p><p>Our results highlight that at low confining pressures (15-45 MPa), the change in elastic velocity is controlled by the sample bulk properites (damage of the medium surrounding the fault), while for higher confining pressures (60-120 MPa), it might be the result of co-seismic damage.</p><p>These preliminary results bring a different interpretation to the seismic velocity drops observed in nature, attributed to co-seismic damage. In our experiments co-seismic damage is not observed, except for high confining pressures (laboratory equivalent for large depths), while the change in P-wave velocity seems to be highly related to combined stress conditions and initial damage around the fault for low confining pressures (laboratory equivalent for shallow depths).</p>

3D P-wave velocity model of Ireland's crust from controlled source tomography

2020 ◽  
Author(s):  
Senad Subašić ◽  
Meysam Rezaeifar ◽  
Nicola Piana Agostinetti ◽  
Sergei Lebedev ◽  
Christopher Bean
Keyword(s):  
Wave Velocity ◽  
Velocity Model ◽  
P Wave ◽  
Uppermost Mantle ◽  
Data Set ◽  
Location Uncertainty ◽  
P Wave Velocity ◽  
1D Model ◽  
Minimum 1D Model ◽  
1D Velocity Model

<p>We present a 3D P-wave velocity model of the crust and uppermost mantle below Ireland. In the absence of local earthquakes, we used quarry and mining blasts recorded on permanent stations in the Irish National Seismic Network (INSN) and during various temporary deployments. We compiled a database of 1,100 events and around 20,000 P-wave arrivals, with each event associated with a known quarry. The source location uncertainty is therefore minimal. Both source and receiver locations are fixed in time and we used repeating events to estimate the travel time uncertainty for each source-receiver combination. We created a starting 1D velocity model from previously available data, and then used VELEST to calculate a preliminary minimum 1D velocity model. The 1D velocity model enabled us to remove outliers from the data set, and to calculate the final minimum 1D model used as the initial model in the 3D tomographic inversion. The resulting 3D P-wave velocity model will shed new light on the 3D crustal structure of Ireland.</p>

scholarly journals Minimum 1D velocity models in Central and Southern Italy: a contribution to better constrain hypocentral determinations

1997 ◽  
Vol 40 (4) ◽  
Author(s):  
C. Chiarabba ◽  
A. Frepoli
Keyword(s):  
Southern Italy ◽  
Deep Structure ◽  
P Wave ◽  
One Dimensional ◽  
Velocity Models ◽  
The Past ◽  
Wave Velocities ◽  
Velocity Gradients ◽  
P Wave Velocity ◽  
Data Yield

We computed one-dimensional ( I D) velocity models and station corrections for Centrai and Southern Italy, in- verting re-picked P-wave alTival times recorded by the Istituto Nazionale di Geofisica seismic network. The re-picked data yield resolved P-wave velocity results and proved to be more suited than bulletin data for de- tailed tomographic studies. Using the improved velocity models, we relocated the most significant earthquakes which occurt.ed in the Apennines in the past 7 years, achieving constrained hypocentral determinations for events within most of the Apenninic belt. The interpretation of the obtained lD velocity models allows us to infer interesting features on the deep structure of the Apennines. Smooth velocity gradients with depth and low P-wave velocities are ob,'ierved beneath the Apennines. We believe that our results are effective to constrain hypocentral locations in Italy and may represent a first step towards more detailed seismotectonic analyses.

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