Preprints
There are 5531 Preprints listed.
Mechanisms for avulsion on alluvial fans: insights from high-frequency topographic data
Published: 2020-12-17
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
Avulsion is a key process in building alluvial fans, but it is also a formidable natural hazard. Based on laboratory experiments monitored with novel high-frequency photogrammetry, we present a new model for avulsion on widely graded gravel fans. Previous experimental studies of alluvial fans have suggested that avulsion occurs in a periodic autogenic cycle, that is thought to be mediated by the [...]
Quantitative uncertainty analysis of gravity disturbance. The case of the Geneva Basin (Switzerland)
Published: 2020-12-17
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Gravity data from the International Gravimetric Bureau and the Gravimetric Atlas of Switzerland have been used to evaluate their application and limitations as a subsurface investigation tool to constrain key geological structures in support of the georesources exploration in the Geneva Basin (GB). In this context, the application of an effective processing workflow able to produce a [...]
Bookshelf Kinematics and the Effect of Dilatation on Fault Zone Inelastic Deformation: Examples from Optical Image Correlation Measurements of the 2019 Ridgecrest Earthquake Sequence
Published: 2020-12-17
Subjects: Physical Sciences and Mathematics
The 2019 Ridgecrest earthquake sequence initiated on July 4th with a series of foreshocks, including a Mw 6.4 event, that culminated a day later with the Mw 7.1 mainshock and resulted in rupture of a set of cross-faults. Here we use sub-pixel correlation of optical satellite imagery to measure the displacement, finite strain and rotation of the near-field coseismic deformation to understand the [...]
The influence of orbital parameters on the North American Monsoon system during the Last Interglacial Period
Published: 2020-12-17
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Environmental Sciences, Hydrology, Oceanography and Atmospheric Sciences and Meteorology
The response of summer precipitation in the western U.S. to climate variability remains a subject of uncertainty. For example, paleoclimate records indicate the North American monsoon (NAM) was stronger and spatially more extensive during the Holocene, whereas recent modeling suggests a weakened NAM response to increasing temperatures. These illustrate diverging pictures of the NAM response to [...]
Climate change research and action must look beyond 2100
Published: 2020-12-16
Subjects: Environmental Sciences, Environmental Studies, Geography, Human Geography, Nature and Society Relations, Oceanography and Atmospheric Sciences and Meteorology, Physical and Environmental Geography, Physical Sciences and Mathematics, Social and Behavioral Sciences
Anthropogenic activity is changing Earth’s climate and ecosystems in ways that are potentially dangerous and disruptive to humans. Greenhouse gas concentrations in the atmosphere continue to rise, ensuring these changes will be felt for centuries beyond 2100, the current benchmark for prediction. Estimating the effects of past, current, and potential future emissions to only 2100 is therefore [...]
Global models for short-term earthquake forecasting and predictive skill assessment
Published: 2020-12-16
Subjects: Physical Sciences and Mathematics
We present rigorous tests of global short-term earthquake forecasts using Epidemic Type Aftershock Sequence models with two different time kernels (one with exponentially tapered Omori kernel (ETOK) and another with linear magnitude dependent Omori kernel (MDOK)). The tests are conducted with three different magnitude cutoffs for the auxiliary catalog (M3, M4 or M5) and two different magnitude [...]
Evidence-based conservation in a changing world: lessons from waterbird individual-based models
Published: 2020-12-16
Subjects: Engineering, Physical Sciences and Mathematics, Social and Behavioral Sciences
Drivers of environmental change are causing novel combinations of pressures on ecological systems. Prediction in ecology often uses understanding of past conditions to make predictions to the future, but such an approach can breakdown when future conditions have not previously been encountered. Individual-based models (IBMs) consider ecological systems as arising from the adaptive behaviour and [...]
Initial model construction for intermediate-period full-waveform inversion of the contiguous US and surrounding regions
Published: 2020-12-15
Subjects: Geophysics and Seismology
Contiguous US is one of regions well instrumented with broadband seismic stations due to the deployment of the EarthScope Transportable Array. Previous studies have provided various 3D seismic wave speed models for the crust and upper mantle with improving resolution. However, discrepancies exist between these models due to the differences in both data sets and tomographic methods, which [...]
Chevrons: origin and relevance for the reconstruction of past wind regimes
Published: 2020-12-15
Subjects: Climate, Earth Sciences, Geology, Geomorphology, Meteorology, Other Life Sciences, Sedimentology, Stratigraphy
Since its first use in the late 80’s, the term chevron has been employed in numerous studies to describe large U- and V-shaped ridges found in or near shorelines worldwide. Most studies have so far focused on Bahamian chevrons that are exclusively of Late Pleistocene age, and on the supposed Holocene chevrons found in S-Madagascar and Australia. In the Bahamas, these deposits have been [...]
Differences in carbon isotope discrimination between angiosperm and gymnosperm woody plants, and their geological significance
Published: 2020-12-13
Subjects: Biogeochemistry, Climate, Geochemistry, Oceanography and Atmospheric Sciences and Meteorology, Paleobiology
For most of the Phanerozoic Eon, Earth’s woody vegetation has been dominated by C3 plants – predominantly gymnosperms - with angiosperms only emerging as the dominant plant group as CO2 declined during the Cenozoic (66 Ma onward). At present, differences in carbon isotope discrimination (Δ13C) between angiosperm and gymnosperm plants are relatively small (2–3 ‰), but an increasing body of [...]
Anatomy of Strike Slip Fault Tsunami-genesis
Published: 2020-12-13
Subjects: Earth Sciences, Engineering, Fluid Dynamics, Geophysics and Seismology, Physical Sciences and Mathematics, Physics
Tsunami generation from earthquake induced seafloor deformations has long been recognized as a major hazard to coastal areas. Strike-slip faulting has generally been believed as insufficient for triggering large tsunamis, except through the generation of submarine landslides. Herein, we demonstrate that ground motions due to strike-slip earthquakes can contribute to the emergence of large [...]
Inference of thermodynamic state in the asthenosphere from anelastic properties, with applications to North American upper mantle
Published: 2020-12-13
Subjects: Earth Sciences, Physical Sciences and Mathematics
Inference of thermodynamic state and full-spectrum mechanical behavior of the lithosphere and asthenosphere is a central problem in geophysics, implicating our understanding of the convection patterns, transient responses and chemical composition of the planet. Anelasticity is responsible for significant relaxation of stress associated with seismic wave propagation in the asthenosphere, while [...]
Atmospheric CO2 estimates for the last 17 million years based on foraminiferal δ11B at Ocean Drilling Program Sites 806 and 807 in the Western Equatorial Pacific
Published: 2020-12-13
Subjects: Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Constraints on the evolution of atmospheric CO2 levels throughout Earth’s history are foundational to our understanding of past variations in climate. Despite considerable effort, estimates of past CO2 levels do not always converge. Here we reconstruct atmospheric CO2 values across major climate transitions over the past 17 million years using the boron isotopic composition (δ11B) of planktic [...]
Mapping Landslides With a Generalized Convolutional Neural Network
Published: 2020-12-13
Subjects: Geomorphology, Other Earth Sciences, Risk Analysis
Landslides are a common secondary hazard triggered by major earthquakes or extreme rainfall events in steep terrains. Rapid mapping of event landslides is crucial to identify the areas affected by damages as well as for effective disaster response. Traditionally, such maps are generated with visual interpretation of remote sensing imagery (manned/unmanned airborne systems or spaceborne sensors) [...]
Saving the world from your couch: The heterogeneous medium-run benefits of COVID-19 lockdowns on air pollution
Published: 2020-12-12
Subjects: Physical Sciences and Mathematics, Social and Behavioral Sciences
In Spring 2020, COVID-19 led to an unprecedented halt in public and economic life across the globe. In an otherwise tragic time, this provides a unique natural experiment to investigate the environmental impact of such a (temporary) ``de-globalization". Here, we estimate the medium-run impact of a battery of COVID-19 related lockdown measures on air quality across 162 countries, going beyond the [...]