Preprints
Filtering by Subject: Geophysics and Seismology
Seismic interferometry in the presence of an isolated noise source
Published: 2022-07-03
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Seismic interferometry gives rise to a correlation wavefield that is closely related to the Green's function under the condition of uniformly distributed noise sources. In the presence of an additional isolated noise source, a second contribution to this wavefield is introduced that emerges from the isolated source location at negative lapse time. These two contributions interfere, which may bias [...]
Harnessing Distributed Acoustic Sensing for Earthquake Early Warning: Magnitude Estimation and Ground Motion Prediction
Published: 2022-06-21
Subjects: Geophysics and Seismology
Earthquake Early Warning (EEW) systems provide seconds to tens of seconds of warning time before potentially-damaging ground motions are felt. For optimal warning times, seismic sensors should be installed as close as possible to expected earthquake sources. However, while the most hazardous earthquakes on Earth occur underwater, most seismological stations are located on-land; precious seconds [...]
SAR and InSAR data linked to soil moisture changes on a temperate raised peatland subjected to a wildfire
Published: 2022-06-17
Subjects: Geophysics and Seismology, Hydrology, Soil Science
Interferometry of Synthetic Aperture Radar (InSAR) can potentially contribute to the cost-effective regional or global monitoring of the degradation and restoration of peatlands. However, there are uncertainties about the links between InSAR results and peatland ecohydrological parameters, especially soil moisture. Here, we analyse the relationships between the temporal evolutions of InSAR [...]
Friction law for earthquake nucleation: size doesn’t matter
Published: 2022-06-17
Subjects: Geology, Geophysics and Seismology
A central question in modeling induced and natural earthquake nucleation is whether fault frictional properties measured in the laboratory are applicable to nature. A laboratory fault is generally just a few centimeters in length-width scale, while natural faults can be hundreds of meters to kilometers in extent. It is unknown whether laboratory fault friction data are applicable even to mesh [...]
Advances in seismic imaging of magma and crystal mush
Published: 2022-06-17
Subjects: Earth Sciences, Geophysics and Seismology, Volcanology
Seismic imaging methods have provided detailed three-dimensional constraints on the physical properties of magmatic systems leading to invaluable insight into the storage, differentiation and dynamics of magma. These constraints have been crucial to the development of our modern understanding of magmatic systems. However, there are still outstanding knowledge gaps resulting from the challenges [...]
Visualizing Best and Worst Case Scenarios in Joint, Constrained, and Time-Dependent Inversions I: Null-Space Transfer and Image-Space Contradictions
Published: 2022-05-31
Subjects: Geophysics and Seismology
Because geophysical inversion is used in many vital societal applications, it is unfortunate that some aspects of inverse methods are so abstract. The difficulty of identifying fundamental behaviors is exacerbated when investigating large non-linear problems which combine multiple datasets into a single model, or which produce multiple models with constraints between them. In this first of [...]
Salt-detached strike-slip faulting, Outer Kwanza Basin, Offshore Angola
Published: 2022-05-25
Subjects: Geology, Geophysics and Seismology, Stratigraphy, Tectonics and Structure
We here use a 3D seismic reflection dataset from Outer Kwanza Basin, offshore Angola to examine the structure and growth of salt-detached strike-slip faults. The faults occur in four, up to 13.8 km-long, NE-trending arrays that are physically linked by restraining bend and releasing stepovers, and which presently overlie Aptian salt and base-salt relief related to pre-salt faulting. We suggest [...]
Using Synthetic Data Trained Convolutional Neural Network For Predicting Sub-Resolution Thin Layers From Seismic Data
Published: 2022-05-19
Subjects: Artificial Intelligence and Robotics, Geology, Geophysics and Seismology
Numerous studies have demonstrated the capability of supervised deep learning techniques for predicting geological features of interest from seismic sections, including features that are difficult to identify using traditional interpretation methods. However, successful application of these techniques in practice has been limited by the difficulty of obtaining large training dataset where seismic [...]
Deep Compressed Seismic Learning for fast location and moment tensor inferences with natural and induced seismicity
Published: 2022-05-19
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Fast detection and characterization of seismic sources is crucial for decision-making and warning systems that monitor natural and induced seismicity. However, besides the laying out of ever denser monitoring networks of seismic instruments, the incorporation of new sensor technologies such as Distributed Acoustic Sensing (DAS) further challenges our processing capabilities to deliver short [...]
Probabilistic Assessment of Antarctic Thermomechanical Structure: Impacts on Ice Sheet Stability
Published: 2022-05-19
Subjects: Earth Sciences, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics, Statistical Methodology
Uncertainty in present-day glacial isostatic adjustment (GIA) rates represents at least 44% of the total gravity-based ice mass balance signal over Antarctica. Meanwhile, physical couplings between solid Earth, sea level and ice dynamics enhance the dependency of the spatiotemporally varying GIA signal on three-dimensional variations in mantle rheology. Improved knowledge of thermomechanical [...]
Complex fault system revealed from 3-D seismic reflection data with deep learning and fault network analysis
Published: 2022-05-13
Subjects: Artificial Intelligence and Robotics, Geology, Geophysics and Seismology, Tectonics and Structure
Understanding where normal faults are is critical to an accurate assessment of seismic hazard, the successful exploration for and production of natural (including low-carbon) resources, and for the safe subsurface storage of CO2. Our current knowledge of normal fault systems is largely derived from seismic reflection data imaging intra-continental rifts and continental margins. However, [...]
Broadband Ocean Bottom Seismometer Noise Properties
Published: 2022-05-13
Subjects: Geophysics and Seismology
We present a new compilation and analysis of broadband ocean bottom seismometer noise properties from 15 years of seismic deployments. We compile a comprehensive dataset of representative four-component (seismometer and pressure gauge) noise spectra and cross-spectral properties (coherence, phase, and admittance) for 551 unique stations spanning 18 US-led experiments. This is matched with a [...]
Rheology of debris-flow materials is controlled by the distance from jamming
Published: 2022-05-13
Subjects: Geophysics and Seismology
Debris flows are dense and fast-moving complex suspensions of soil and water that threaten lives and infrastructure. Assessing the hazard potential of debris flows requires predicting yield and flow behavior. Reported measurements of rheology for debris-flow slurries are highly variable and sometimes contradictory, due to heterogeneity in grain size, shape, chemical composition, and solid-volume [...]
The signature of lithospheric anisotropy at post-subduction continental margins: new insight from XKS splitting analysis in northern Borneo
Published: 2022-05-02
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
The relative paucity of recent post-subduction environments globally has meant that, so far, little is known about tectonic processes that occur during and after subduction termination, as previously convergent tectonic plates adjust to the new stress regime. The region of Southeast Asia that now encompasses northern Borneo has been host to two sequential episodes of subduction—both now [...]
Tidal Turbine Array Modelling using Goal-Oriented Mesh Adaptation
Published: 2022-04-29
Subjects: Civil and Environmental Engineering, Fluid Dynamics, Geophysics and Seismology, Numerical Analysis and Computation, Partial Differential Equations
Purpose: To examine the accuracy and sensitivity of tidal array performance assessment by numerical techniques applying goal-oriented mesh adaptation. Methods: The goal-oriented framework is designed to give rise to adaptive meshes upon which a given diagnostic quantity of interest (QoI) can be accurately captured, whilst maintaining a low overall computational cost. We seek to improve the [...]