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Preprints

Filtering by Subject: Geophysics and Seismology

Adaptive Finetuning of 3D CNNs with Interpretation Uncertainty for Seismic Fault Prediction

Ahmad Mustafa, Ghassan AlRegib, Reza Rastegar

Published: 2023-06-20
Subjects: Geophysics and Seismology, Signal Processing

3D CNNs can exploit the full extent of spatial information in seismic volumes to predict faults. They require large quantities of training data, but this issue has been mitigated by training such networks with large amounts of synthetic training data to apply afterwards on real datasets. Because of domain shift, pre-trained networks may fail to perform as expected, emphasizing the need to [...]

Applying Machine Learning to Characterize and Transport the Relationship Between Seismic Structure and Surface Heat Flux

Michael H Ritzwoller, Shane Zhang

Published: 2023-06-15
Subjects: Geophysics and Seismology, Glaciology

Geothermal heat flux beneath the Greenland and Antarctic ice sheets is an important boundary condition for ice sheet dynamics. Subglacial heat flux is rarely measured directly, so it has been inferred indirectly from proxies (e.g. seismic structure, magnetic Curie depth, surface topography). We seek to improve understanding of the relationship between heat flux and one such proxy---seismic [...]

Seismic Stratigraphy of Contourite Drift Deposits Associated with the Loop Current on the Eastern Campeche Bank, Gulf of Mexico

Christopher Michael Lowery, Ligia Perez Cruz, Jaime Urrutia Fucugauchi, et al.

Published: 2023-06-08
Subjects: Geophysics and Seismology, Oceanography, Sedimentology, Stratigraphy

The Loop Current is a key component of global circulation via the northward transport of warm, salty water and an important influence on Gulf of Mexico hydrography. Understanding how the Loop Current will respond to ongoing anthropogenic warming is critically important, but the history of the Loop Current is poorly known. Here, we present the results of a high resolution (3-8 m) multichannel [...]

Automated shear-wave splitting analysis for single- and multi- layer anisotropic media

Thomas Samuel Hudson, Joseph Asplet, Andrew Walker

Published: 2023-06-07
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Shear-wave velocity anisotropy is present throughout the earth. The strength and orientation of anisotropy can be observed by shear-wave splitting (birefringence) accumulated between earthquake sources and receivers. Seismic deployments are getting ever larger, increasing the number of earthquakes detected and the number of source-receiver pairs. Here, we present a new software package, SWSPy, [...]

A diffuse interface method for earthquake rupture dynamics based on a phase-field model

Jorge Nicolas Hayek, Dave A May, Casper Pranger, et al.

Published: 2023-06-02
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

In traditional modeling approaches, earthquakes are often depicted as displacement discontinuities across zero-thickness surfaces embedded within a linear elastodynamic continuum. This simplification, however, overlooks the intricate nature of natural fault zones and may fail to capture key physical phenomena integral to fault processes. Here, we propose a diffuse interface description for [...]

Full vector inversion of magnetic microscopy images using Euler deconvolution as a priori information

Gelson F. Souza-Junior, Leonardo Uieda, Ricardo Ivan Ferreira da Trindade, et al.

Published: 2023-06-02
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Paleomagnetic data are usually obtained from whole cylindric samples, where the signal results from the sum of magnetic moments from hundreds of thousands to millions of magnetic particles within the sample volume. This usually includes both stable and unstable remanence carriers. Recently, magnetic microscopy techniques allowed the investigation of individual grains by directly imaging their [...]

Formulating and Solving the Data-Consistent Geophysical Inverse Problem for Subsurface Modeling Applications

Alex Miltenberger, Lijing Wang, Tapan Mukerji, et al.

Published: 2023-05-27
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Probability

Today, most probabilistic geophysical inverse problems are formulated using one of two methods: (1) conditional probability and Bayes’ Theorem, or (2) Tarantola’s theory of intersecting probability densities. More recently, a third inverse problem formulation based on pushforward probability measures was proposed, termed “data-consistent inversion”. Many practical problems can be cast into any of [...]

Integrated Formation Attenuation and Multiple Generator Identification from Multi-well VSP Data

Fahdi Maula, Marsha Sakina, Haryo Trihutomo

Published: 2023-05-25
Subjects: Geophysics and Seismology

The Vertical Seismic Profile (VSP) is a widely used technique for extracting velocity information and seismic well tie purposes. However, the full potential of VSP data remains underutilized. This study explores the broader applicability of VSP data beyond its conventional usage by investigating its benefits for seismic data processing and interpretation. Advanced VSP products, incorporating [...]

Linking 3D long-term slow-slip cycle models with rupture dynamics: the nucleation of the 2014 Mw 7.3 Guerrero, Mexico earthquake

Duo Li, Alice-Agnes Gabriel

Published: 2023-05-25
Subjects: Geophysics and Seismology

Slow slip events (SSEs) have been observed in spatial and temporal proximity to megathrust earthquakes in various subduction zones, including the 2014 $M_\mathrm{w}$7.3 Guerrero, Mexico earthquake which was preceded by a $M_\mathrm{w}$ 7.6 SSE. However, the underlying physics connecting SSEs to earthquakes remains elusive. Here, we link 3D slow-slip cycle models with dynamic rupture simulations [...]

A Stability Analysis of Neural Networks and Its Application to Tsunami Early Warning

Donsub Rim, Sanah Suri, Sanghyun Hong, et al.

Published: 2023-05-14
Subjects: Geophysics and Seismology, Hydrology, Numerical Analysis and Computation

Neural networks (NNs) enable precise modeling of complicated geophysical phenomena but are sensitive to small input changes. In this work, we present a new method for analyzing this instability in NNs. We focus our analysis on adversarial examples, test-time inputs with carefully-crafted human-imperceptible perturbations that expose the worst-case instability in a model's predictions. Our [...]

Slip-stuck kinematics of fault surfaces in laboratory experiments: implications for heterogeneous slip distributions during earthquake events

Uddalak Biswas, Manaska Mukhopadhyay, Nibir Mandal

Published: 2023-05-05
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure

Combining field observations with analogue laboratory experiments, this study aims to use surface-roughness characteristics as an indicator of the heterogeneous slip partitioning along shear surfaces. We investigated the roughness of shear surfaces in sheared quartzite of the Singhbhum Shear Zone, eastern India, and identified two distinct kinematic domains: slip zone and stuck zone, marked by [...]

Lateral Heterogeneity Analysis Using Multiwell ZVSP Unsupervised Machine Learning Classification

Fahdi Maula

Published: 2023-05-03
Subjects: Geophysics and Seismology

In 3D and 2D surface seismic interpretation, seismic waveform shapes and attributes can identify facies and reservoir parameters laterally with more details than traditional amplitude mapping. Herein, a method on 1D zero offset VSP (ZVSP) data was adapted, giving a unique perspective of lateral heterogeneity analysis using VSP seismic waveform shapes and attributes. The downgoing wavefield of VSP [...]

Active Learning with Deep Autoencoders for Seismic Facies Interpretation

Ahmad Mustafa, Ghassan AlRegib

Published: 2023-04-26
Subjects: Geophysics and Seismology

Machine learning-assisted seismic interpretation tasks require large quantities of labeled data annotated by expert interpreters, which is a costly and time-consuming process. Where existing works to minimize dependence on labeled data assume the data annotation process to already be completed, active learning---a field of machine learning---works by selecting the most important training samples [...]

A comparative study of transfer learning methodologies and causality for seismic inversion with temporal convolutional networks

Ahmad Mustafa, Ghassan AlRegib

Published: 2023-04-25
Subjects: Geophysics and Seismology

Machine learning-based seismic inversion methods suffer from high labeled data requirement in the absence of which they may fail to generalize. Recent data-driven inversion methodologies based on temporal convolutional networks use 2-D sequence models and transfer learning to unburden the algorithm from high training data requirements. Such methods are restricted in that they only model seismic [...]

In-situ frictional behavior of subducting sediment in the shallow Nankai Trough

Hanaya Okuda, Manami Kitamura, Miki Takahashi, et al.

Published: 2023-04-22
Subjects: Geology, Geophysics and Seismology, Sedimentology, Tectonics and Structure

The transition from smectite to illite at around the depth with temperature of ~150 °C has long been hypothesized as one of controlling factors of the updip limit depth of the seismogenic zone of subduction zones. Although illite has a higher friction coefficient than smectite, previous friction experiments have little reported that the smectite-illite transition accompanies the transition from [...]

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