Preprints
Filtering by Subject: Geophysics and Seismology
Growing primordial continental crust self-consistently in global mantle convection models
Published: 2019-05-10
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The majority of continental crust formed during the hotter Archean was composed of Tonalite-Trondhjemite-Granodiorite (TTG) rocks. In contrast to the present-day loci of crust formation around subduction zones and intra-plate tectonic settings, TTGs are formed when hydrated basalt melts at garnet-amphibolite, granulite or eclogite facies conditions. Generating continental crust requires a two [...]
Probabilistic space- and time-interaction modeling of main-shock earthquake rupture occurrence
Published: 2019-04-28
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Physical Sciences and Mathematics, Statistical Models, Statistics and Probability, Structural Engineering
This paper presents a probabilistic formulation for modeling earthquake rupture processes of mainshocks. A correlated multivariate Bernoulli distribution is used to model rupture occurrence. The model captures time interaction through the use of Brownian passage-time (BPT) distributions to assess rupture interarrival in multiple sections of the fault, and it also considers spatial interaction [...]
Bayesian parameter estimation for space and time interacting earthquake rupture model using historical and physics-based simulated earthquake catalogs
Published: 2019-04-25
Subjects: Civil and Environmental Engineering, Civil Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Physical Sciences and Mathematics, Risk Analysis
This paper presents a robust parameter estimation technique for a probabilistic earthquake hazard model that captures time and space interactions between earthquake mainshocks. The approach addresses the existing limitations of parameter estimation techniques by developing a Bayesian formulation and leveraging physics-based simulated synthetic catalogs to expand the limited datasets of historical [...]
Influence of dissolution on frictional properties of carbonate faults
Published: 2019-04-25
Subjects: Civil and Environmental Engineering, Civil Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Physical Sciences and Mathematics
Velocity stepping experiments have been performed on a simulated calcite gouge using an annular shear apparatus to investigate the effect of dissolution on the frictional properties of a carbonate fault. The tested material was put in contact with hydrochloric acid at different concentration in order to dissolve the grains. Particle size analysis shows that the small grains tend to disappear due [...]
A physics-based approach of deep interseismic creep for viscoelastic strike-slip earthquake cycle models
Published: 2019-04-24
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Most geodetic inversions of surface deformation rates consider the depth distribution of interseismic fault slip-rate to be time invariant. However, some numerical simulations show down-dip penetration of dynamic rupture into regions with velocity-strengthening friction, with subsequent up-dip propagation of the locked-to-creeping transition. Recently, Bruhat & Segall (2017) developed a new [...]
A Scalable Algorithm for Cross-correlations of Compressed Ambient Seismic Noise
Published: 2019-04-17
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Companies and academic geophysicists are increasingly collecting continuous seismic data on denser arrays, and are looking to a variety of lossy compression methods to store and quickly access this data. Some researchers turn to ambient noise interferometry for low-cost near-surface imaging to avoid to cost and permitting required for active source experiments, but the computation can be very [...]
Finite frequency inversion of cross-correlation amplitudes for ambient noise source directivity estimation
Published: 2019-04-15
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We present a new method for determining the azimuthal variation of ambient seismic noise sources, that combines the computational speed and simplicity of traditional approaches with the rigour of waveform-inversion-based approaches to noise-source estimation. This method is based on a previously developed theoretical framework of sensitivity kernels for cross-correlation amplitudes. It performs a [...]
Efficient 3D large-scale forward-modeling and inversion of gravitational fields in spherical coordinates with application to lunar mascons
Published: 2019-04-11
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
An efficient forward modeling algorithm for calculation of gravitational fields in spherical coordinates is developed for 3D large‐scale gravity inversion problems. 3D Gauss‐Legendre quadrature (GLQ) is used to calculate the gravitational fields of mass distributions discretized into tesseroids. Equivalence relations in the kernel matrix of the forward‐modeling are exploited to decrease storage [...]
Characterising strong force networks produced during granular shear using percolation methods: Revealing the bridge between local grain scale processes and macroscopic sliding
Published: 2019-04-08
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Other Earth Sciences, Physical Sciences and Mathematics, Physics, Tectonics and Structure
Faults, landslides and subglacial till often contain accumulations of granular debris. Their macroscopic motion is at least to some extent determined by the processes operating in this sheared granular material. A valid question in these environments is how the local behaviour at the individual granular contacts actually sums up to influence macroscopic sliding. Laboratory experiments and [...]
Fast non-linear gravity inversion in spherical coordinates with application to the South American Moho
Published: 2019-04-07
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Estimating the relief of the Moho from gravity data is a computationally intensive non-linear inverse problem. What is more, the modeling must take the Earths curvature into account when the study area is of regional scale or greater. We present a regularized non-linear gravity inversion method that has a low computational footprint and employs a spherical Earth approximation. To achieve this, we [...]
Comment on “Earthquake-induced prompt gravity signals identified in dense array data in Japan” by Kimura et al.
Published: 2019-04-05
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
A recent work by Kimura et al. (2019) (hereafter referred to as K19) claims to provide the first observational constraints on the prompt elastogravity signals (PEGS) induced by an earthquake. To make their claim, the authors argue that the observations shown in Vallée et al. (2017) (hereafter referred to as V17) are spurious and their modeling inaccurate. Here we show that K19’s claim is invalid [...]
Earthquake cycle modeling of the Cascadia subduction zone
Published: 2019-04-05
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The Cascadia subduction zone hosts great $\mathrm{M}_\mathrm{W} > 8.5$ earthquakes, but studying these events is hindered by our short observational record. Earthquake cycle simulation provides an alternative window into the behavior of the subduction zone. Here, we present simulations over 3,800 years, 14 ruptures and hundreds of slow slip events on a high-fidelity geometric representation of [...]
Ridge Subduction and Afterslip Control Aftershock Distribution of the 2016 Mw 7.8 Ecuador Earthquake
Published: 2019-04-02
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We characterise the aftershock sequence following the 2016 Mw=7.8 Pedernales earthquake. More than 10,000 events were detected and located, with magnitudes up to 6.9. Most of the aftershock seismicity results from interplate thrust faulting, but we also observe a few normal and strike-slip mechanisms. Seismicity extends for more than 300 km along strike, and is constrained between the trench and [...]
Boundary element methods for earthquake modeling with realistic 3D geometries
Published: 2019-04-01
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Boundary element methods have become a foundational tool in earthquake science for the modeling of earthquake cycle kinematics. Despite their wide use and convenience typical rectangular and triangular constant slip dislocation methods produce stress singularities at the edges of every element rendering these models physically unrealistic. As we demonstrate, in an earthquake cycle simulation [...]
Observation and explanation of spurious seismic signals emerging in teleseismic noise correlations
Published: 2019-04-01
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Deep body waves have been reconstructed from seismic noise correlations in recent studies. The authors note their great potential for deep-Earth imaging. In addition to the expected physical seismic phases, some spurious arrivals having no correspondence in earthquake seismograms are observed from the noise correlations. The origins of the noise-derived body waves have not been well understood. [...]