Filtering by Subject: Geophysics and Seismology

On the effect of grain fragmentation on frictional instabilities in faults with granular gouge

Di Wang, Jan Carmeliet, Wei Zhou, Omid Dorostkar

Published: 2020-07-16
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics

The evolution of frictional strength during stick-slip dynamics of a fault system is key to understanding the earthquake nucleation and rupture patterns. In mature faults, granular gouge is produced by wear, comminution or fragmentation during tectonic movements. In this work, we introduce a fragmentation model in the simulation of a sheared granular fault to explore the influence of grain [...]


Jian Sun, Kristopher Innanen, Chao Huang

Published: 2020-07-13
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

The determination of subsurface elastic property models is crucial in quantitative seismic data processing and interpretation. This problem is commonly solved by deterministic physical methods, such as tomography or full waveform inversion (FWI). However, these methods are entirely local, and require accurate initial models. Deep learning represents a plausible class of methods for seismic [...]

Tracking and measuring of clay shrinking and swelling using spaceborne remote sensing

André Burnol, Michael Foumelis, Sébastien Gourdier, Jacques Deparis, Daniel Raucoules

Published: 2020-07-13
Subjects: Earth Sciences, Geophysics and Seismology, Hydrology, Physical Sciences and Mathematics

New capabilities for measuring and monitoring are needed to improve the shrink/swell hazard. A new French experimental site at Chaingy (Centre-Val de Loire) has been instrumented using extensometers at the surface and soil moisture sensors in the clay layer. Here we show by direct comparison between remote and in situ data for a period longer than three years that the vertical ground [...]

Fracture mechanics of rate-and-state faults and fluid injection induced slip

Dmitry Garagash

Published: 2020-07-08
Subjects: Earth Sciences, Engineering, Environmental Sciences, Geophysics and Seismology, Oil, Gas, and Energy, Physical Sciences and Mathematics, Physics

Propagation of a slip transient on a fault with rate-and-state dependent friction resembles a fracture which near tip region is characterized by large departure of the slip velocity and fault strength from the steady-state sliding. We develop a near tip solution to describe this unsteady dynamics, and obtain the fracture energy Gc, dissipated in overcoming strength-excursion away from [...]

Deep spatial transformers for autoregressive data-driven forecasting of geophysical turbulence

Ashesh Kumar Chattopadhyay, Mustafa Mustafa, Pedram Hassanzadeh, Karthik Kashinath

Published: 2020-07-06
Subjects: Artificial Intelligence and Robotics, Atmospheric Sciences, Climate, Computer Sciences, Dynamical Systems, Earth Sciences, Environmental Sciences, Fluid Dynamics, Geophysics and Seismology, Mathematics, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics

A deep spatial transformer based encoder-decoder model has been developed to autoregressively predict the time evolution of the upper layers stream function of a two-layered quasi-geostrophic (QG) system without any information about the lower layers stream function. The spatio-temporal complexity of QG flow is comparable to the complexity of 500hPa Geopotential Height (Z500) of fully coupled [...]

Seismic swarm preceding the 2017 Mount Agung eruption in Bali (Indonesia) enhanced by the matched filter approach

Dimas Sianipar, Emi Ulfiana, Renhard Sipayung

Published: 2020-07-02
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Intense swarm seismicity took place before the 2017 Mount Agung eruption in Bali (Indonesia). However, the earthquake sequences were not well documented. In addition, there was a substantial delay between the peak of the seismic activity (late September) and the onset of the impending eruption (late November). We applied waveform-based hypocenter relocation and matched filter technique (MFT) to [...]

Machine learning and fault rupture: a review

Christopher X. Ren, Claudia Hulbert, Paul A. Johnson, Bertrand Rouet‐Leduc

Published: 2020-07-02
Subjects: Artificial Intelligence and Robotics, Computer Sciences, Earth Sciences, Geophysics and Seismology, Mathematics, Physical Sciences and Mathematics, Theory and Algorithms

Geophysics has historically been a data-driven field, however in recent years the exponential increase of available data has lead to increased adoption of machine learning techniques and algorithm for analysis, detection and forecasting applications to faulting. This work reviews recent advances in the application of machine learning in the study of fault rupture ranging from the laboratory to [...]

Seismological Expression of the Iron Spin Crossover in Ferropericlase in the Earth’s Lower Mantle

Grace E. Shephard, Christine Houser, John Hernlund, Juan J. Valencia-Cardona, Reidar Trønnes, Renata Wentzkovitch

Published: 2020-06-30
Subjects: Earth Sciences, Geochemistry, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics, Physics, Quantum Physics, Tectonics and Structure

The two most abundant minerals on Earth which together make up over 90% of the Earth’s lower mantle are (Mg,Fe)O-ferropericlase (Fp) and (Mg,Fe)SiO3-bridgmanite (Bm). Iron in Fp undergoes a high-spin to low-spin (HS-LS) crossover that influences density, viscosity, elasticity, thermal conductivity, and elemental partitioning, however, the predicted effects of this transition are not apparent in [...]

Geological Facies Modeling Based on Progressive Growing of Generative Adversarial Networks (GANs)

Suihong Song, Tapan Mukerji, Jiagen Hou

Published: 2020-06-22
Subjects: Artificial Intelligence and Robotics, Computer Sciences, Earth Sciences, Geology, Geophysics and Seismology, Hydrology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy

Geological facies modeling has long been studied to predict subsurface resources. In recent years, generative adversarial networks (GANs) have been used as a new method for geological facies modeling with surprisingly good results. However, in conventional GANs, all layers are trained concurrently, and the scales of the geological features are not considered. In this study, we propose to train [...]

Excessive seismicity over a limited source: the August 2019 earthquake swarm near Mt. Salak in West Java (Indonesia)

Dimas Sianipar, Renhard Sipayung, Emi Ulfiana

Published: 2020-06-22
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

The triggering mechanism of swarm-like seismicity in the Java Island of Indonesia is generally not well understood. Understanding earthquake swarm phenomena and monitoring in various tectonic settings can be improved by the detection of micro-earthquakes; however, such a catalog is not available due to various reasons including the existing limited seismic network and using an outdated algorithm [...]

Sensing earth and environment dynamics by telecommunication fiber-optic sensors: An urban experiment in Pennsylvania USA

Tieyuan Zhu, Junzhu Shen, Eileen R Martin

Published: 2020-06-18
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Continuous seismic monitoring of the Earths near surface (top 100 meters), especially with improving the resolution and extent of data both in space and time, would yield more accurate insights about the effect of extreme weather events (e.g. flooding or drought) and climate change on the Earths surface and subsurface systems. However, continuous long-term seismic monitoring, especially in urban [...]

The 3D thermal field across the Alpine orogen and its forelands and the relation to seismicity

Cameron Spooner, Magdalena Scheck-Wenderoth, Mauro Cacace, Hans-Jürgen Götze, Elco Luijendijk

Published: 2020-06-17
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Temperature exerts a first order control on rock strength, principally via thermally activated creep deformation and on the distribution at depth of the brittle-ductile transition zone. The latter can be regarded as the lower bound to the seismogenic zone, thereby controlling the spatial distribution of seismicity within a lithospheric plate. As such, models of the crustal thermal field are [...]

The Whole Antarctic Ocean Model (WAOM v1.0): Development and Evaluation

Ole Richter, David Gwyther, Benjamin K. Galton-Fenzi, Kaitlin Naughten

Published: 2020-06-13
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

The Regional Ocean Modeling System (ROMS), including an ice shelf component, has been applied on a circum-Antarctic domain to derive estimates of ice shelf basal melting. Significant improvements made compared to previous models of this scale are the inclusion of tides and a horizontal spatial resolution of 2 km, which is sufficient to resolve onshelf heat transport by bathymetric troughs and [...]

Mechanical Response of Shallow Crust to Groundwater Storage Variations: Inferences from Deformation and Seismic Observations in the Eastern Southern Alps, Italy

Francesco Pintori, Enrico Serpelloni, Laurent Longuevergne, Alexander Garcia-Aristizabal, Maria Elina Belardinelli, Licia Faenza, Lucio D’Alberto, Adriano Gualandi

Published: 2020-06-06
Subjects: Earth Sciences, Geophysics and Seismology, Hydrology, Physical Sciences and Mathematics

Changes in continental water storage generate vertical surface deformation, induce crustal stress perturbations and modulate seismicity rates. However, the degree to which regional changes in terrestrial water content influence crustal stresses and the occurrence of earthquakes remains an open problem. We show how changes in groundwater storage, computed for a ~1000 km^2 basin, focus deformation [...]

Breakup Without Borders: How Continents Speed Up and Slow Down During Rifting

Martina Ulvrova, Sascha Brune, Simon Williams

Published: 2020-05-30
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure

Relative plate motions during continental rifting result from the interplay of local with far-field forces. Here, we study the dynamics of rifting and breakup using large-scale numerical simulations of mantle convection with self-consistent evolution of plate boundaries. We show that continental separation follows a characteristic evolution with four distinctive phases: (1) An initial slow [...]


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