Preprints
Filtering by Subject: Geophysics and Seismology
Statistical Evaluation of Seismic Velocity Models of Permafrost
Published: 2023-06-30
Subjects: Geophysics and Seismology, Geotechnical Engineering
The warming climate in high-latitude permafrost regions is leading to permafrost degradation. Estimating seismic velocity in permafrost can help predict the geomechanical properties of permafrost and provide information for planning and designing resilient civil infrastructure in cold regions. Seismic velocities of permafrost are mainly influenced by three components in permafrost: soil grains, [...]
THIN SHEET AUTOMATIC INTERPRETATION OF DIKE SWARM MAGNETIC TRANSECTS USING REGULARIZED SECOND DERIVATIVES
Published: 2023-06-30
Subjects: Geophysics and Seismology
Dike swarms are major continental structures recording large igneous provinces and crustal extension processes generating rifts and sedimentary basins. A key point in dike swarm studies is determining a minimum number of dikes that are necessary to explain the observed magnetic anomalies and inferences about position and depth for specific unities. We develop an automatic interpretation procedure [...]
Explainable Machine Learning for Hydrocarbon Prospect Risking
Published: 2023-06-20
Subjects: Geophysics and Seismology, Statistics and Probability
Hydrocarbon prospect risking integrates information from multiple geophysical data and modalities to arrive at a probability of success for a given prospect. The DHI database of drilled prospects gathers data from prospects drilled around the world in multiple geologic settings in one central knowledge base. A major goal of interest to geophysicists is to understand the impact of various seismic [...]
Adaptive Finetuning of 3D CNNs with Interpretation Uncertainty for Seismic Fault Prediction
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
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
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
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
Published: 2023-06-01
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
Published: 2023-06-01
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
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
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
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
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
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
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 [...]