scholarly journals Relationships among Forearc Structure, Fault Slip, and Earthquake Magnitude: Numerical Simulations with Applications to the Central Chilean Margin

2021 ◽  
Author(s):  
Xiaoyu Wang ◽  
Julia Morgan ◽  
Nathan Bangs
Keyword(s):  
Numerical Simulations ◽  
Fault Slip ◽  
Earthquake Magnitude ◽  
Chilean Margin

scholarly journals A comparison between rate-and-state friction and microphysical models, based on numerical simulations of fault slip

2018 ◽  
Vol 733 ◽  
pp. 273-295 ◽  
Author(s):  
M.P.A. van den Ende ◽  
J. Chen ◽  
J.-P. Ampuero ◽  
A.R. Niemeijer
Keyword(s):  
Numerical Simulations ◽  
Fault Slip ◽  
Rate And State Friction

scholarly journals Predicting Fault Slip via Transfer Learning

2021 ◽  
Author(s):  
Kun Wang ◽  
Christopher Johnson ◽  
Kane Bennett ◽  
Paul Johnson
Keyword(s):  
Machine Learning ◽  
Numerical Simulations ◽  
Transfer Learning ◽  
Laboratory Experiments ◽  
Laboratory Data ◽  
Fault Slip ◽  
Geophysical Data ◽  
Training Data ◽  
Data Sets ◽  
Earthquake Cycle

Abstract Data-driven machine-learning for predicting instantaneous and future fault-slip in laboratory experiments has recently progressed markedly due to large training data sets. In Earth however, earthquake interevent times range from 10's-100's of years and geophysical data typically exist for only a portion of an earthquake cycle. Sparse data presents a serious challenge to training machine learning models. Here we describe a transfer learning approach using numerical simulations to train a convolutional encoder-decoder that predicts fault-slip behavior in laboratory experiments. The model learns a mapping between acoustic emission histories and fault-slip from numerical simulations, and generalizes to produce accurate results using laboratory data. Notably slip-predictions markedly improve using the simulation-data trained-model and training the latent space using a portion of a single laboratory earthquake-cycle. The transfer learning results elucidate the potential of using models trained on numerical simulations and fine-tuned with small geophysical data sets for potential applications to faults in Earth.

Comparison of NGA-West2 Directivity Models

2014 ◽  
Vol 30 (3) ◽  
pp. 1199-1221 ◽  
Author(s):  
Paul Spudich ◽  
Badie Rowshandel ◽  
Shrey K. Shahi ◽  
Jack W. Baker ◽  
Brian S.-J. Chiou
Keyword(s):  
Numerical Simulations ◽  
Narrow Band ◽  
Scale Up ◽  
Strike Slip ◽  
Earthquake Magnitude ◽  
Zero Level ◽  
Geographic Distributions

Five directivity models have been developed based on data from the NGA-West2 database and based on numerical simulations of large strike-slip and reverse-slip earthquakes. All models avoid the use of normalized rupture dimension, enabling them to scale up to the largest earthquakes in a physically reasonable way. Four of the five models are explicitly “narrow-band” (in which the effect of directivity is maximum at a specific period that is a function of earthquake magnitude). Several strategies for determining the zero-level for directivity have been developed. We show comparisons of maps of the directivity amplification. This comparison suggests that the predicted geographic distributions of directivity amplification are dominated by effects of the models’ assumptions, and more than one model should be used for ruptures dipping less than about 65 degrees.

scholarly journals A fault slip model to study earthquakes due to pore pressure perturbations

2021 ◽  
Author(s):  
Saumik Dana ◽  
Birendra Jha
Keyword(s):  
Pore Pressure ◽  
Geothermal Energy ◽  
Energy Production ◽  
Pressure Change ◽  
Fault Slip ◽  
Earthquake Magnitude ◽  
Climate Mitigation ◽  
Slip Model ◽  
Pressure Perturbations

The burgeoning need to sequester anthropogenic CO_2 for climate mitigation and the need for energy sustenance leading upto enhanced geothermal energy production has made it incredibly critical to study potential earthquakes due to fluid activity in the subsurface. These earthquakes result from reactivation of faults in the subsurface due to pore pressure perturbations. In this work, we provide a framework to model fault slip due to pore pressure change leading upto quantifying the earthquake magnitude.

scholarly journals Predicting fault slip via transfer learning

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kun Wang ◽  
Christopher W. Johnson ◽  
Kane C. Bennett ◽  
Paul A. Johnson
Keyword(s):  
Machine Learning ◽  
Numerical Simulations ◽  
Transfer Learning ◽  
Laboratory Experiments ◽  
Fault Slip ◽  
Geophysical Data ◽  
Training Data ◽  
Data Sets ◽  
Earthquake Cycle ◽  
Fault Friction

AbstractData-driven machine-learning for predicting instantaneous and future fault-slip in laboratory experiments has recently progressed markedly, primarily due to large training data sets. In Earth however, earthquake interevent times range from 10’s-100’s of years and geophysical data typically exist for only a portion of an earthquake cycle. Sparse data presents a serious challenge to training machine learning models for predicting fault slip in Earth. Here we describe a transfer learning approach using numerical simulations to train a convolutional encoder-decoder that predicts fault-slip behavior in laboratory experiments. The model learns a mapping between acoustic emission and fault friction histories from numerical simulations, and generalizes to produce accurate predictions of laboratory fault friction. Notably, the predictions improve by further training the model latent space using only a portion of data from a single laboratory earthquake-cycle. The transfer learning results elucidate the potential of using models trained on numerical simulations and fine-tuned with small geophysical data sets for potential applications to faults in Earth.

Saturation mechanism and generated viscosity in gravito-turbulent accretion disks

2020 ◽  
Vol 640 ◽  
pp. A53
Author(s):  
L. Löhnert ◽  
S. Krätschmer ◽  
A. G. Peeters
Keyword(s):  
Growth Rate ◽  
Numerical Simulations ◽  
Accretion Disks ◽  
Gravitational Instability ◽  
Turbulent Viscosity ◽  
Radial Distance ◽  
Maximum Growth ◽  
Wave Number ◽  
Radiative Cooling ◽  
Mixing Length

Here, we address the turbulent dynamics of the gravitational instability in accretion disks, retaining both radiative cooling and irradiation. Due to radiative cooling, the disk is unstable for all values of the Toomre parameter, and an accurate estimate of the maximum growth rate is derived analytically. A detailed study of the turbulent spectra shows a rapid decay with an azimuthal wave number stronger than ky−3, whereas the spectrum is more broad in the radial direction and shows a scaling in the range kx−3 to kx−2. The radial component of the radial velocity profile consists of a superposition of shocks of different heights, and is similar to that found in Burgers’ turbulence. Assuming saturation occurs through nonlinear wave steepening leading to shock formation, we developed a mixing-length model in which the typical length scale is related to the average radial distance between shocks. Furthermore, since the numerical simulations show that linear drive is necessary in order to sustain turbulence, we used the growth rate of the most unstable mode to estimate the typical timescale. The mixing-length model that was obtained agrees well with numerical simulations. The model gives an analytic expression for the turbulent viscosity as a function of the Toomre parameter and cooling time. It predicts that relevant values of α = 10−3 can be obtained in disks that have a Toomre parameter as high as Q ≈ 10.

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