Preprints
Filtering by Subject: Physical Sciences and Mathematics
Array-based seismic measurements of OSIRIS-REx's re-entry
Published: 2024-08-23
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Planetary Sciences
The return home of the OSIRIS-REx spacecraft in September 2023 marked only the fifth time that an artificial object entered the Earth's atmosphere at interplanetary velocities. Although rare, such events serve as valuable analogues for natural meteoroid re-entries; enabling study of hypersonic dynamics, shockwave generation, and acoustic-to-seismic coupling. Here, we report on the signatures [...]
Complex and confined laboratory ruptures explain scaling of the critical slip distance for earthquake faulting
Published: 2024-08-22
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
Earthquake sequences in nature are complex, exhibiting a range of magnitudes and slip behaviors. In contrast, earthquake-like instabilities generated on frictional faults in the laboratory and in continuum numerical models are usually quasi-periodic with a smaller range of magnitudes and durations. The discrepancy, especially apparent for cm-sized samples used in lab friction experiments, has [...]
Larger and Steadier Warming since 1850 from Harmonized Land and Ocean Temperature Records
Published: 2024-08-22
Subjects: Physical Sciences and Mathematics
Accurate historical temperature estimates are crucial for understanding current warming levels and informing policy decisions. Trends in global land and ocean temperatures diverge, however, before 1945. Inter-calibration of coastal land-ocean temperatures indicates that this divergence arises from under-corrected biases in sea-surface temperature linked to late 19th century instrumentation [...]
The Effect of Rayleigh-Love Coupling in an Anisotropic Medium
Published: 2024-08-17
Subjects: Physical Sciences and Mathematics
It is well known that for a weakly anisotropic medium, at angular frequency $\omega$ and propagation azimuth $\psi$ Rayleigh and Love wave phase speeds are given approximately by $V(\omega,\psi) = A_0 + A_{2c} \cos 2 \psi + A_{2s} \sin 2 \psi + A_{4c} \cos 4 \psi + A_{4s} \sin 4 \psi$. Previous theories of the propagation of surface waves in anisotropic media based on non-degenerate perturbation [...]
Spatial Variability of Water Temperature within the White River Basin, Mount Rainier National Park, Washington
Published: 2024-08-16
Subjects: Life Sciences, Physical Sciences and Mathematics
Water temperature is a primary control on the occurrence and distribution of cold-water species. Rivers draining Mount Rainier in western Washington, including the White River along its northern flank, support several cold-water fish populations, but the spatial distribution of water temperatures, particularly during late-summer base flow between August and September, and the climatic, [...]
The influence of wildfire smoke on ambient chemical species concentrations in the contiguous US
Published: 2024-08-14
Subjects: Environmental Sciences, Physical Sciences and Mathematics
Wildfires are a significant contributor to ambient air pollution and pose a growing public health threat in many parts of the world. Increased wildfire activity over the past few decades has exacerbated smoke exposure across the US, yet our understanding of how wildfire influences specific chemicals and their resulting concentration in smoke remains incomplete. We combine 15 years of daily [...]
A methodologically robust densification function for snow on multiyear Arctic sea ice
Published: 2024-08-13
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
Comparative Analysis of SVM and CNN for Hyperspectral Image Classification
Published: 2024-08-13
Subjects: Computer Engineering, Computer Sciences, Other Computer Sciences, Physical Sciences and Mathematics
This paper presents a comparative analysis of tra- ditional machine learning methods and Convolutional Neural Networks (CNNs) for hyperspectral image classification. Utilizing the Indian Pines dataset, we explore the efficacy of Principal Component Analysis (PCA) combined with a Support Vector Machine (SVM) classifier against a deep learning approach involving CNNs. Our methodology includes [...]
Rapid Fault Leakage Modeling for CO2 Storage in Saline Aquifers
Published: 2024-08-12
Subjects: Chemical Engineering, Earth Sciences, Engineering, Geology, Petroleum Engineering, Physical Sciences and Mathematics, Risk Analysis
Simulating the fluid flow along fault zones at different scales is essential for predicting the CO2 leakage and containment during injection and storage. However, this can be challenging, especially in the early stages of a storage project when knowledge of the reservoir and caprock is limited and the cost of obtaining the relevant data is high. This study proposes a tool for fast screening of [...]
Expanded constraints on chemical weathering reactions and carbon cycling beneath the Antarctic Ice Sheet
Published: 2024-08-11
Subjects: Physical Sciences and Mathematics
Ice sheets may influence the global carbon cycle by releasing chemical weathering products and carbon from basal environments. However, limited data describing subglacial biogeochemical cycles beneath Antarctic and Greenland ice leaves open fundamental questions regarding the feedbacks between climate, ice sheets, and the carbon cycle. Most notably: does subglacial chemical weathering beneath ice [...]
The cyclical nature of normal fault growth: Insights from 4D analogue models
Published: 2024-08-10
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Exploring how normal faults evolve is important for understanding the dynamic processes underlying the initiation and evolution of rift systems. Early-stage fault growth has been largely under-explored due to resolution limitations in seismic reflection data and the lack of three-dimensional exposures in the field. Physical analogue modelling offers a unique way to visualize and analyse [...]
Remote sensing large-wood storage downstream of reservoirs during and after dam removal: Elwha River, Washington, USA
Published: 2024-08-09
Subjects: Physical Sciences and Mathematics
Large wood is an integral part of many rivers, often defining river-corridor morphology and habitat, but its occurrence, magnitude, and evolution in a river system are much less well understood than the sedimentary and hydraulic components, and due to methodological limitations, have seldom previously been mapped in substantial detail. We present a new method for this, representing a substantial [...]
A global C-staggered composite model for shallow water equations 1 with latitude-longitude grid and reductions in the polar regions
Published: 2024-08-07
Subjects: Applied Mathematics, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
To develop a numerical method for global geophysical fluids, we usually need to choose a spherical grid and numerical approximations to represent the partial derivative equations. Some alternatives include the use of finite differences or finite volumes with latitude-longitude or reduced grids. Each of these cases has some advantages and also some limitations. This paper presents a comparison [...]
Incongruent chemical weathering and adsorption of neodymium drive modulation of neodymium isotope composition of global riverine particulate matter
Published: 2024-08-07
Subjects: Physical Sciences and Mathematics
We report incongruent weathering and differential release of radiogenic neodymium (143Nd) to challenge the widely accepted congruent behaviour of Nd isotopes during weathering of rocks. Investigating two basaltic weathering profiles of the Rajmahal Volcanic Province in India, the incongruent behaviour of minerals and Nd isotopes were established. These results contradict the premise of invariant [...]
Constraining Earth's core composition from inner core nucleation.
Published: 2024-08-02
Subjects: Earth Sciences, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics, Planetary Geophysics and Seismology, Planetary Mineral Physics, Planetary Sciences