Preprints
Filtering by Subject: Physical Sciences and Mathematics
Recrystallization of ice enhances the creep and vulnerability to fracture of ice shelves
Published: 2021-03-08
Subjects: Earth Sciences, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics
The initiation of fractures and fast flow in floating regions of Antarctica have the potential to destabilize large regions of the grounded ice sheet, leading to significant sea-level rise. While observations have shown rapid, localized deformation and damage in the margins of fast-flowing glaciers, there remain gaps in our understanding of how rapid deformation affects the viscosity and [...]
Topographic response to Neogene variations in slab geometry, climate and drainage reorganization in the Northern Andes of Colombia
Published: 2021-03-06
Subjects: Physical Sciences and Mathematics
The tropical Northern Andes of Colombia are one the world's most biodiverse places, offering an ideal location for unraveling the linkages between the geodynamic forces that build topography and the evolution of the biota that inhabit it. In this study, we utilize geomorphic analysis to characterize the topography of the Western and Central Cordilleras of the Northern Andes. We supplement our [...]
Mechanical properties of quartz sand and gypsum powder (plaster) mixtures: implications for laboratory model analogues for the Earth’s upper crust
Published: 2021-03-06
Subjects: Physical Sciences and Mathematics
Granular materials are a useful analogue for the Earth’s crust in laboratory models of deformation. Constraining their mechanical properties is critical for such model’s scaling and interpretation. Much information exists about monomineralic granular materials, such as quartz sand, but the mechanical characteristics of bimineralic mixtures, such as commonly-used quartz sand mixed with gypsum [...]
Assessing Margin-Wide Rupture Behaviors along the Cascadia Megathrust with 3-D Dynamic Rupture Simulations
Published: 2021-03-05
Subjects: Physical Sciences and Mathematics
From California to British Columbia, the Pacific Northwest coast bears an omnipresent earthquake and tsunami hazard from the Cascadia subduction zone. Multiple lines of evidence suggests that magnitude eight and greater megathrust earthquakes have occurred - the most recent being 321 years ago (i.e., 1700 A.D.). Outstanding questions for the next great megathrust event include where it will [...]
Crisis at the Salton Sea: The Vital Role of Science
Published: 2021-03-04
Subjects: Atmospheric Sciences, Biogeochemistry, Chemistry, Climate, Earth Sciences, Environmental Chemistry, Environmental Public Health, Environmental Sciences, Environmental Studies, Geochemistry, Geology, Geomorphology, Hydrology, Medicine and Health Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Public Health, Social and Behavioral Sciences
The Salton Sea—a hypersaline, terminal lake in southern California—is in crisis. A combination of mismanagement and competition among federal, state and local agencies has hindered efforts to address declining lake levels and unstable water chemistry. This delay has heightened the public health threat to regional communities as retreating shorelines expose dry lakebed— a source of potentially [...]
Use of machine learning to estimate statistics of the posterior distribution in probabilistic inverse problems - an application to airborne EM data.
Published: 2021-03-03
Subjects: Earth Sciences, Physical Sciences and Mathematics
The solution to a probabilistic inverse problem is the posterior probability distribution for which a full analytic expression is rarely possible. Sampling methods are therefore often used to generate a sample from the posterior. Decision-makers may be interested in the probability of features related to model parameters (for example existence of a pollution or the cumulative clay thickness) [...]
Estimating Ocean Surface Currents from Satellite Observable Quantities with Machine Learning
Published: 2021-03-03
Subjects: Physical Sciences and Mathematics
Global surface currents are usually inferred from directly observed quantities like sea-surface height, wind stress by applying diagnostic balance relations (like geostrophy and Ekman flow), which provide a good approximation of the dynamics of slow, large-scale currents at large scales and low Rossby numbers. However, newer generation satellite altimeters (like the upcoming SWOT mission) will [...]
Seasonal dispersal of fjord meltwaters as an important source of iron to coastal Antarctic phytoplankton
Published: 2021-03-03
Subjects: Physical Sciences and Mathematics
Glacial meltwater from the western Antarctic Ice Sheet is hypothesized to be an important source of cryospheric iron, fertilizing the Southern Ocean, yet its trace metal composition and factors which control its dispersal remain poorly constrained. Here we characterize meltwater iron sources in a heavily glaciated western Antarctic Peninsula (WAP) fjord. Using dissolved and particulate ratios of [...]
Research 339: High-resolution climate projections for Ireland. A multi-model ensemble approach
Published: 2021-03-02
Subjects: Physical Sciences and Mathematics
The method of regional climate modelling was employed to assess the impacts of a warming climate on the 21st-century climate of Ireland. The regional climate model (RCM) simulations were run at high spatial resolution (3.8 and 4 km), the first systematic study of its kind at this scale, thus allowing a better evaluation of the local effects of climate change. To address the issue of uncertainty, [...]
Extending full-plate tectonic models into deep time: Linking the Neoproterozoic and the Phanerozoic
Published: 2021-03-02
Subjects: Physical Sciences and Mathematics
Recent progress in plate tectonic reconstructions has seen models move beyond the classical idea of continental drift by attempting to reconstruct the full evolving configuration of tectonic plates and plate boundaries. A particular problem for the Neoproterozoic and Cambrian is that many existing interpretations of geological and palaeomagnetic data have remained disconnected from younger, [...]
Closure of the Proterozoic Mozambique Ocean was instigated by a late Tonian plate reorganization event
Published: 2021-03-02
Subjects: Physical Sciences and Mathematics
Plate reorganization events involve fundamental changes in lithospheric plate-motions and can influence the lithosphere-mantle system as well as both ocean and atmospheric circulation through bathymetric and topographic changes. Here, we compile published data to interpret the geological record of the Neoproterozoic Arabian-Nubian Shield and integrate this with a full-plate tectonic [...]
Birth of a large volcanic edifice offshore Mayotte via lithosphere-scale dike intrusion
Published: 2021-03-02
Subjects: Physical Sciences and Mathematics
Volcanic eruptions shape Earth’s surface and provide a window into deep Earth processes. How the primary asthenospheric melts form, pond and ascend through the lithosphere is, however, still poorly understood. Since 10 May 2018, magmatic activity has occurred offshore eastern Mayotte (North Mozambique channel), associated with large surface displacements, very-low-frequency earthquakes and [...]
Is there a Speed Limit for the Thermal Steady-State Assumption in Continental Rifts?
Published: 2021-03-01
Subjects: Earth Sciences, Physical Sciences and Mathematics
The lithosphere is often assumed to reside in a thermal steady-state when quantitatively describing the temperature distribution in continental interiors and sedimentary basins, but also at active plate boundaries. Here, we investigate the applicability limit of this assumption at slowly deforming continental rifts. To this aim, we assess the tectonic thermal imprint in numerical experiments that [...]
Temperature variability and extremes both affect economic growth
Published: 2021-02-26
Subjects: Environmental Sciences, Physical Sciences and Mathematics
Changes in temperature averages, variability, and extremes may all independently affect economic growth under climate change. Kotz et al. (2021) show that temperature variability reduces growth, but find no significant effect of temperature extremes. Recreating their results, here we show that temperature extremes do indeed affect growth independently from the effects of variability. Our results [...]
3D modeling of long-term slow slip events along the flat slab segment in the Guerrero Seismic Gap, Mexico
Published: 2021-02-26
Subjects: Physical Sciences and Mathematics
During the last two decades, quasi-periodic long-term slow-slip events (SSEs) of magnitudes up to Mw7.5 have been observed about every 4 years in the Guerrero Seismic Gap. Here we present numerical simulations of the long-term SSE cycles along the 3D slab geometry of central Mexico. Our model accounts for the hydrated oceanic crust in the framework of rate-and-state friction. The modeled SSE [...]