Preprints
Filtering by Subject: Geophysics and Seismology
A Mixed, Unified Forward/Inverse Framework for Earthquake Problems: Fault Implementation and Coseismic Slip Estimate
Published: 2021-10-06
Subjects: Earth Sciences, Geophysics and Seismology, Numerical Analysis and Scientific Computing, Physical Sciences and Mathematics, Tectonics and Structure
We introduce a new finite-element (FE) based computational framework to solve forward and inverse elastic deformation problems for earthquake faulting via the adjoint method. Based on two advanced computational libraries, FEniCS and hIPPYlib for the forward and inverse problems, respectively, this framework is flexible, transparent, and easily extensible. We represent a fault discontinuity [...]
Improved Seismic Monitoring with OBS Deployment in the Arctic: A Pilot Study from Offshore Western Svalbard
Published: 2021-10-04
Subjects: Geophysics and Seismology
The mid-ocean ridge system is the main source of earthquakes within the Arctic region. The earthquakes are recorded on the permanent land-based stations in the region, although smaller earthquakes remain undetected. In this study, we make use of three Ocean Bottom Seismographs (OBSs) that were deployed offshore western Svalbard, along the spreading ridges. The OBS arrival times were used to [...]
Seismic and Acoustic Monitoring of Submarine Landslides: Ongoing Challenges, Recent Successes and Future Opportunities
Published: 2021-10-04
Subjects: Geology, Geophysics and Seismology, Oceanography, Sedimentology
Submarine landslides pose a hazard to coastal communities due to the tsunamis they can generate, and can damage critical seafloor infrastructure, such as the network of cables that underpin global data transfer and communications. These mass movements can be orders of magnitude larger than their onshore equivalents and are found on all of the world’s continental margins; from coastal zones to [...]
Oblique convergence causes both thrust and strike-slip ruptures during the 2021 M 7.2 Haiti earthquake
Published: 2021-10-01
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
A devastating magnitude 7.2 earthquake struck Southern Haiti on 14 August 2021. The earthquake caused severe damage and over 2000 casualties. Resolving the earthquake rupture process can provide critical insights into hazard mitigation. Here we use integrated seismological analyses to obtain the rupture history of the 2021 earthquake. We find the earthquake first broke a blind thrust fault and [...]
Rapid characterisation of the extremely large landslide threatening the Rules Reservoir (Southern Spain)
Published: 2021-10-01
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Geology, Geomorphology, Geophysics and Seismology
When an active landslide is first identified in an artificial reservoir, a comprehensive study has to be quickly conducted to analyse the possible hazard that it may represent to such a critical infrastructure. This paper presents the case of the El Arrecife Landslide, located in a slope of the Rules Reservoir (Southern Spain), as an example of geological and motion data integration for [...]
An anisotropic equation of state for high pressure, high temperature applications
Published: 2021-09-25
Subjects: Condensed Matter Physics, Geophysics and Seismology, Materials Science and Engineering, Mineral Physics, Physical Sciences and Mathematics, Planetary Geophysics and Seismology, Planetary Mineral Physics
This paper presents a strategy for consistently extending isotropic equations of state to model anisotropic materials over a wide range of pressures and temperatures under nearly hydrostatic conditions. The method can be applied to materials of arbitrary symmetry. The paper provides expressions for the deformation gradient tensor, the lattice parameters, the isothermal elastic compliance tensor [...]
Structural controls on earthquake rupture revealed by the 2020 Mw 6.0 Jiashi earthquake (Kepingtag belt, SW Tian Shan, China)
Published: 2021-09-24
Subjects: Geology, Geophysics and Seismology, Tectonics and Structure
The Kepingtag (Kalpin) fold-and-thrust belt of the southern Chinese Tian Shan is characterized by active shortening and intense seismic activity. Geological cross-sections and seismic reflection profiles suggest thin-skinned, northward-dipping thrust sheets detached in an Upper Cambrian décollement. The January 19 2020 Mw 6.0 Jiashi earthquake provides an opportunity to investigate how coseismic [...]
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 [...]