Preprints
Filtering by Subject: Geophysics and Seismology
Deep Deconvolution for Traffic Analysis with Distributed Acoustic Sensing Data
Published: 2021-09-23
Subjects: Artificial Intelligence and Robotics, Geophysics and Seismology, Transportation Engineering
Distributed Acoustic Sensing (DAS) is a novel vibration sensing technology that can be employed to detect vehicles and to analyse traffic flows using existing telecommunication cables. DAS therefore has great potential in future "smart city" developments, such as real-time traffic incident detection. Though previous studies have considered vehicle detection under relatively light traffic [...]
Imaging an Underwater Basin and its Resonance Modes using Optical Fiber Distributed Acoustic Sensing
Published: 2021-09-22
Subjects: Earth Sciences, Geophysics and Seismology
Distributed acoustic sensing is an ideal tool for ambient noise tomography owing to the dense spatial measurements and the ability to continuously record in harsh environments, such as underwater. We demonstrate the ability to image a complex underwater basin using ambient noise recorded on a fiber deployed offshore Greece. A two-dimensional shear-wave velocity model was derived by analyzing [...]
Shear-wave Anisotropy in the Earth’s Inner Core
Published: 2021-09-17
Subjects: Earth Sciences, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics
Earth’s inner core anisotropy is widely used to infer the deep Earth's evolution and present dynamics. Many compressional-wave anisotropy models have been proposed based on seismological observations. In contrast, inner-core shear-wave (J-wave) anisotropy – on a par with the compressional-wave anisotropy – has been elusive. Here we present a new class of the J-wave anisotropy observations [...]
Stress-based forecasting of induced seismicity with instantaneous earthquake failure functions: Applications to the Groningen Gas Reservoir
Published: 2021-09-15
Subjects: Geophysics and Seismology
In this study we use the Groningen gas field to test a new method to assess stress changes due to gas extraction and forecast induced seismicity. We take advantage of the detailed knowledge of the reservoir geometry and production history, and of the availability of surface subsidence measurements and high quality seismicity data. The subsurface is represented as a homogeneous isotropic linear [...]
Three-dimensional fluid-driven stable frictional ruptures
Published: 2021-09-13
Subjects: Earth Sciences, Engineering, Environmental Sciences, Geophysics and Seismology, Oil, Gas, and Energy, Physical Sciences and Mathematics, Physics
We investigate the quasi-static growth of a fluid-driven frictional shear crack that propagates in mixed mode (II+III) on a planar fault interface that separates two identical half-spaces of a three-dimensional solid. The fault interface is characterized by a shear strength equal to the product of a constant friction coefficient and the local effective normal stress. Fluid is injected into the [...]
Assessment pebble virtual velocity from combined active RFID fixed stations and geophones
Published: 2021-09-06
Subjects: Geomorphology, Geophysics and Seismology, Hydrology
The monitoring of coarse sediment transport is a domain teeming with technical innovations and methodological developments aimed at improving the characterization of bedload processes at different spatial and temporal scales. Radio frequency identification (RFID) technology has improved sediment tracking experiments, allowing the characterization of processes at the individual particle and [...]
Drone-mounted GPR surveying: flight-height considerations for diffraction-based velocity analysis
Published: 2021-09-06
Subjects: Earth Sciences, Geophysics and Seismology, Other Earth Sciences
Recent studies highlight the potential of the drone platform for ground-penetrating radar (GPR) surveying. Most guidance for optimizing drone flight heights is based on maximizing the image quality of target responses, but no study yet considers the impact on diffraction traveltimes. Strong GPR velocity contrasts across the air-ground interface introduce significant refraction effects that [...]
An overview of multimethod imaging approaches in environmental geophysics
Published: 2021-08-30
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Quantitative characterization of subsurface properties is critical for many environmental applications and serves as the basis to simulate and better understand dynamic subsurface processes. Geophysical imaging methods allow to image subsurface property distributions and monitor their spatio-temporal changes in a minimally invasive manner. While it is widely agreed upon that models integrating [...]
Fault rock heterogeneity can produce fault weakness and reduce fault stability
Published: 2021-08-30
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Tectonics and Structure
Geological heterogeneity is abundant in crustal fault zones; however, its role in controlling the mechanical behaviour of faults is poorly constrained. Here, we present laboratory friction experiments on laterally heterogeneous faults, with patches of strong, rate-weakening quartz gouge and weak, rate-strengthening clay gouge. The experiments show that the heterogeneity leads to a significant [...]
Linking earthquake magnitude-frequency statistics and stress in visco-frictional fault zone models
Published: 2021-08-27
Subjects: Geophysics and Seismology
The ability to estimate the likelihood of given earthquake magnitudes is critical for seismic hazard assessment. Earthquake magnitude-recurrence statistics are empirically linked to stress, yet which fault-zone processes explain this link remains debated. We use numerical models to reproduce the interplay between viscous creep and frictional sliding of a fault-zone, for which inter-seismic [...]
Parsimonious velocity inversion applied to the Los Angeles Basin, CA
Published: 2021-08-24
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The proliferation of dense arrays promises to improve our ability to image geological structures at the scales necessary for accurate assessment of seismic hazard. However, combining the resulting local high-resolution tomography with existing regional models presents an ongoing challenge. We developed a framework based on the level-set method that infers where local data provide meaningful [...]
Spectral boundary integral method for simulating static and dynamic fields from a fault rupture in a poroelastodynamic solid
Published: 2021-08-24
Subjects: Applied Mechanics, Geophysics and Seismology, Partial Differential Equations, Tribology
The spectral boundary integral method is popular for simulating fault, fracture, and frictional processes at a planar interface. However, the method is less commonly used to simulate off-fault dynamic fields. Here we develop a spectral boundary integral method for poroelastodynamic solid. The method has two steps: first, a numerical approximation of a convolution kernel and second, an efficient [...]
The Optimal Correlation Detector?
Published: 2021-08-19
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Correlation detectors are now used routinely in seismology to detect occurrences of signals bearing close resemblance to a reference waveform. They facilitate the detection of low-amplitude signals in significant background noise that may elude detection using energy detectors, and they associate a detected signal with a source location. Many seismologists use the fully normalized correlation [...]
Safety and Belonging in the Field: A Checklist for Educators
Published: 2021-08-19
Subjects: Atmospheric Sciences, Biogeochemistry, Climate, Cosmochemistry, Earth Sciences, Education, Environmental Education, Environmental Health and Protection, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Environmental Studies, Fresh Water Studies, Geochemistry, Geographic Information Sciences, Geography, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Higher Education, Human Geography, Hydrology, Life Sciences, Meteorology, Mineral Physics, Natural Resource Economics, Natural Resources and Conservation, Natural Resources Management and Policy, Nature and Society Relations, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Oil, Gas, and Energy, Other Earth Sciences, Other Environmental Sciences, Other Geography, Other Oceanography and Atmospheric Sciences and Meteorology, Other Planetary Sciences, Outdoor Education, Paleobiology, Paleontology, Physical and Environmental Geography, Physical Sciences and Mathematics, Planetary Biogeochemistry, Planetary Geochemistry, Planetary Geology, Planetary Geomorphology, Planetary Geophysics and Seismology, Planetary Glaciology, Planetary Hydrology, Planetary Mineral Physics, Planetary Sciences, Planetary Sedimentology, Remote Sensing, Sedimentology, Social and Behavioral Sciences, Soil Science, Spatial Science, Speleology, Stratigraphy, Sustainability, Tectonics and Structure, Volcanology, Water Resource Management
Ensuring taught fieldwork is a positive, generative, collective, and valuable experience for all participants requires considerations beyond course content. To guarantee safety and belonging, participants’ identities (backgrounds and protected characteristics) must be considered as a part of fieldwork planning and implementation. Furthermore, getting fieldwork right is an important step in [...]
Reflection Seismic Thermometry
Published: 2021-08-12
Subjects: Geology, Geophysics and Seismology
The North Viking Graben (NVG) is part of the mature North Sea Basin petroleum province and designated as a major carbon storage basin for NW Europe. It has been extensively drilled over five decades with an abundance of well and seismic data in the public domain. As such it serves as an excellent setting to demonstrate the efficacy of a reflection seismic data led approach to predicting [...]