Preprints
There are 5726 Preprints listed.
An apparatus for measuring nonlinear viscoelasticity of minerals at high temperature
Published: 2020-10-30
Subjects: Physical Sciences and Mathematics
We describe a high-temperature, uniaxial creep apparatus designed to investigate nonlinear attenuation of materials over a wide range of temperatures (25–1300°C) using forced oscillations combined with a bias stress. This apparatus is primarily designed for investigation of minerals and rocks with high melting temperatures. An oscillatory compressional stress is used to determine attenuation and [...]
Extreme curvature of shallow magma pathways controlled by competing stresses
Published: 2020-10-30
Subjects: Earth Sciences, Physics
Eruptions at shield volcanoes often occur from radially aligned linear fissures fed by blade-like magma-filled cracks (dykes). The fissures of the 2018 Sierra Negra eruption were scattered on the flank of the volcano. Space-borne radar interferometric data (InSAR) revealed that, unexpectedly, part of the eruption was fed by a 15 km long, tortuous and flat-lying crack (sill). Here we develop a [...]
Rayleigh wave H/V ratio measurement from ambient noise cross-correlations, and its sensitivity to Vp: a numerical study
Published: 2020-10-30
Subjects: Earth Sciences, Geophysics and Seismology
The promise of passive seismology has increasingly been realized in recent years. Given the expense in installing and maintaining seismic station networks, it is important to extract as much information from the measurements as possible. In this context, the ellipticity or H/V amplitude ratio of Rayleigh waves can prove to be a valuable observable in ambient noise seismology due to its [...]
The Emergent Influence of Anthropogenic Warming on Global Crop Yields
Published: 2020-10-30
Subjects: Atmospheric Sciences, Climate, Environmental Sciences, Social and Behavioral Sciences, Statistical Methodology
A large literature on “detection and attribution” has now demonstrated the influence of anthropogenic greenhouse gas emissions on a range of physical climate variables. Social and economic outcomes are known to be sensitive to climate change, but directly connecting observed changes to anthropogenic forcing is challenging. Here I estimate the effect of anthropogenic warming on global crop yield [...]
Reproducible Research and GIScience: an evaluation using GIScience conference papers
Published: 2020-10-29
Subjects: Geographic Information Sciences
GIScience conference authors and researchers face the same computational reproducibility challenges as authors and researchers from other disciplines who use computers to analyse data. Here, to assess the reproducibility of GIScience research, we apply a rubric for assessing the reproducibility of 75 conference papers published at the GIScience conference series in the years 2012-2018. The rubric [...]
Urban Air Quality Modeling Using Low-Cost Sensor Network and Data Assimilation in the Aburra Valley, Colombia
Published: 2020-10-29
Subjects: Applied Mathematics, Atmospheric Sciences, Environmental Monitoring
The use of low air quality networks has been increasing in recent years to study urban pollution dynamics. Here we show the evaluation of the operational Aburra Valley's low-cost network against the official monitoring network. The results show that the PM2.5 low-cost measurements are very close to those observed by the official network. Additionally, the low-cost allows a higher spatial [...]
Megathrust Modeling Workshop Report
Published: 2020-10-29
Subjects: Earth Sciences
The Planning for a Modeling Collaboratory for Subduction Zone Science (MCS) Research Coordination Network (RCN) is one of three RCNs funded by the National Science Foundation (NSF) following the 2016 Subduction Zone Observatory (SZO) workshop. The MCS RCN aims to facilitate the development of the integrative earthquake and volcano modeling component of SZ4D, the MCS, and explore how computational [...]
Morphodynamic modelling of beach cusp formation: the role of wave forcing and sediment composition
Published: 2020-10-29
Subjects: Physical Sciences and Mathematics
A field of beach cusps formed during a field experiment at Nha Trang Beach, Vietnam, under accretive conditions. The measured data was used to set-up morphodynamic simulations in XBeach, which was able to simulate cusp formation from an initially long-shore uniform beach profile. Several types of simulations were run in order to observe the resulting variation in mean cusp dimensions (length, [...]
High-frequency global wavefields for local 3D structures by wavefield injection and extrapolation
Published: 2020-10-28
Subjects: Geophysics and Seismology
Earth structure is multiscale, and seismology remains the primary means of deciphering signatures from small structures over large distances. To enable this at the highest resolution, we present a flexible injection and extrapolation type hybrid framework that couples wavefields from a precomputed global database of accurate Green’s functions with a local three dimensional (3-D) method of [...]
Studying the initiation of volcanic eruptions: Time for a petrological perspective.
Published: 2020-10-28
Subjects: Earth Sciences, Volcanology
Volcano monitoring is essential for mitigating the risks associated with volcanic activity. As monitoring becomes more sophisticated and widespread, there is a growing need for understanding the relationship between different monitoring records and magmatic processes occurring at depth. This is particularly relevant to the processes that initiate eruptions after the extended periods of repose and [...]
Responses of tropical marine ecosystems to climate change impacts and their treatment in biogeochemical ecosystem models
Published: 2020-10-27
Subjects: Life Sciences, Physical Sciences and Mathematics
To predict the effects of climate change on marine ecosystems and the effectiveness of intervention and mitigation strategies, we need reliable marine ecosystem response models such as biogeochemical models that reproduce climate change effects. We reviewed marine ecosystem parameters and processes that are modified by climate change and examined their representations in biogeochemical ecosystem [...]
The large-scale troughs on Asteroid 4 Vesta accommodate opening-mode displacement
Published: 2020-10-27
Subjects: Physical Sciences and Mathematics
The Dawn mission at Asteroid 4 Vesta revealed two sets of enormous linear structures. Both sets are troughs—linear, negative-relief landforms—with one spanning around two-thirds of the equator and the other set located in the northern hemisphere. Previous work evaluated the shapes of the troughs and interpreted them to be analogous to grabens, which are landforms caused by faulting; however, an [...]
Improving mechanical behaviour of collapsible soils by grouting active clay nanoparticles
Published: 2020-10-27
Subjects: Engineering, Physical Sciences and Mathematics
The primary geotechnical concern of collapsible soils such as loess is their hydromechanical instability. During (re)wetting, metastable aggregates disintegrate leading soil to collapse under the applied load or self-weight. In situ chemical stabilisation, such as grouting, is a favoured option to improve the mechanical behaviour of soils; however, the low permeability of loess limits the [...]
Impacts of a regional multi-year insect defoliation event on seasonal runoff ratios and instantaneous streamflow characteristics
Published: 2020-10-26
Subjects: Forest Sciences, Hydrology, Terrestrial and Aquatic Ecology, Water Resource Management
Repeated moderate severity forest disturbances can cause short- and long-term shifts in ecosystem processes. Prior work has found that stand-replacing disturbances (e.g., clear-cutting) increases streamflow in temperate forests, but streamflow responses to repeated moderate severity disturbances are more equivocal. This study examined a moderate disturbance caused by an unexpected population [...]
Assimilation of GNSS Reflectometry Delay-Doppler Maps into Global Ocean Surface Wind Analyses
Published: 2020-10-26
Subjects: Earth Sciences
Direct remote sensing observations (e.g. radar backscatter, radiometer brightness temperature, or radio occultation bending angle) are often more effective for use in data assimilation (DA) than the corresponding geophysical retrievals (e.g. ocean surface winds, soil moisture, or atmospheric water vapor). In the particular case of Global Navigation Satellite System Reflectometry (GNSS-R), the [...]