Preprints
Filtering by Subject: Physical Sciences and Mathematics
On the statistical significance of foreshock sequences in Southern California
Published: 2019-11-05
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Earthquake foreshocks may provide information that is critical to short-term earthquake forecasting. However, foreshocks are far from ubiquitously observed, which makes the interpretation of ongoing seismic sequences problematic. Based on a statistical analysis, Trugman & Ross (2019) suggested that as much as 72% of all mainshocks in Southern California is preceded by foreshock sequences. In [...]
Equifinality, Sloppiness, and emergent model structures of mechanistic soil biogeochemical models
Published: 2019-11-05
Subjects: Biogeochemistry, Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics, Soil Science
Biogeochemical models increasingly consider the microbial control of car- bon cycling in soil. The major current challenge is to validate mechanistic descriptions of microbial processes and predicted system responses against experimental observations. We analyzed soil biochemical models of different complexity regarding parameter identifiability using information geometry, i.e. a model is [...]
The global lake area, climate, and population dataset
Published: 2019-11-05
Subjects: Environmental Monitoring, Environmental Sciences, Other Environmental Sciences, Physical Sciences and Mathematics
An increasing population in conjunction with a changing climate necessitates a detailed understanding of water abundance at multiple spatial and temporal scales. Remote sensing has provided massive data volumes to track fluctuations in water quantity, yet contextualizing water abundance with other local, regional, and global trends remains challenging by often requiring large computational [...]
Gulf Stream and Kuroshio Current are synchronized
Published: 2019-11-05
Subjects: Atmospheric Sciences, Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Observational records show that sea surface temperatures along the Gulf Stream and Kuroshio tend to synchronize at decadal time scales. This synchronization, which we refer to as the Boundary Current Synchronization (BCS), is reproduced in global climate models with high spatial resolution. Both in observations and model simulations, BCS is associated with meridional migrations of the atmospheric [...]
Neogene-Recent Reactivation of Jurassic-age Faults in Southern Vietnam, with Implications for the Extrusion of Indochina
Published: 2019-11-02
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
Onshore Vietnam contains a complex series of faults coupled with a diffuse igneous province that has been active since the mid-Miocene. However, there are several conflicting fault maps in the literature and no consensus concerning the relative age of mapped faults and Neogene basalt flows, which becomes problematic when trying to use structural data to distinguish between competing tectonic [...]
Detection and temperature estimation of gas flares with nocturnal Landsat OLI
Published: 2019-11-02
Subjects: Earth Sciences, Environmental Sciences, Oil, Gas, and Energy, Physical Sciences and Mathematics
Natural gas flaring is a worldwide polluting activity carried out during oil production. Satellite imagery has emerged as a low-cost, objective tool to measure and monitor gas flaring. Since 2012, hectometre-resolution infrared imagery from the Suomi NPP VIIRS sensor has been used to operationally monitor global gas flaring (Elvidge et al. 2016). Since 2013, nocturnal acquisitions of Landsat 8 [...]
The variation and visualisation of elastic anisotropy in rock-forming minerals
Published: 2019-11-01
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics, Tectonics and Structure
All minerals behave elastically, a rheological property that controls their ability to support stress, strain and pressure, the nature of acoustic wave propagation and influences subsequent plastic (i.e. permanent, non-reversible) deformation. All minerals are intrinsically anisotropic in their elastic properties – that is, they have directional variations that are related to the configuration [...]
A unique bacteriohopanetetrol stereoisomer of marine anammox
Published: 2019-11-01
Subjects: Biogeochemistry, Earth Sciences, Physical Sciences and Mathematics
Anaerobic ammonium oxidation (anammox) is a significant process for bioavailable nitrogen removal from marine systems. A bacteriohopanetetrol (BHT) isomer, with unknown stereochemistry, eluting later than BHT using high performance liquid chromatography (HPLC), was detected in ‘Ca. Scalindua profunda’ and proposed as a biomarker for anammox in marine paleo-environments. Four non-marine, [...]
The Earthquake Arrest Zone
Published: 2019-11-01
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Earthquake ruptures are generally considered to be cracks that propagate as fracture or frictional slip on preexisting faults. Crack models have been used to describe the spatial distribution of fault offset and the associated static stress changes along a fault, and have implications for friction evolution and the underlying physics of rupture processes. However, field measurements that could [...]
Pre-deliquescent water uptake in deposited nanoparticles observed with in situ ambient pressure X-ray photoelectron spectroscopy
Published: 2019-10-31
Subjects: Atmospheric Sciences, Chemistry, Oceanography and Atmospheric Sciences and Meteorology, Physical Chemistry, Physical Sciences and Mathematics
In this work we study the adsorption, or uptake, of water onto deposited inorganic sodium chloride and organic malonic acid and sucrose nanoparticles at low relative humidities from 0 to 16%. We employ the surface sensitive ambient pressure x-ray photoelectron spectroscopy technique, which has a detection sensitivity from parts per thousand. Our results show that water is adsorbed on sodium [...]
Deep Unsupervised 4D Seismic 3D Time-Shift Estimation with Convolutional Neural Networks
Published: 2019-10-31
Subjects: Applied Statistics, Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Statistics and Probability
We present a novel 3D warping technique for the estimation of 4D seismic time-shift. This unsupervised method provides a diffeomorphic 3D time shift field that includes uncertainties, therefore it does not need prior time-shift data to be trained. This results in a widely applicable method in time-lapse seismic data analysis. We explore the generalization of the method to unseen data both in the [...]
Constructing statutory energy goal compliant wind and solar PV infrastructure pathways
Published: 2019-10-31
Subjects: Environmental Studies, Geography, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Social and Behavioral Sciences, Spatial Science
Concerns over climate change have led governments around the world to establish a range of renewable, low-carbon energy goals. Plans for meeting these targets vary widely in their ambition, specificity, and time horizons. Wind and solar electricity generation will feature prominently in future energy systems that meet these renewable, low-carbon energy goals. Implementing large-scale wind and [...]
Observing Rivers with Varying Spatial Scales
Published: 2019-10-31
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
The NASA/CNES Surface Water and Ocean Topography (SWOT) mission will estimate global river discharge using remote sensing. Synoptic remote sensing data extends in situ point measurements, but, at any given point, is generally less accurate. We address two questions: 1)What are the scales at which river dynamics can be observed, given spatial sampling and measurement noise characteristics? 2) Is [...]
Did deglaciation of the Greenland ice sheet cause a large earthquake and tsunami around 10,600 years ago?
Published: 2019-10-31
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Due to their large mass, ice sheets induce significant stresses in the Earth’s crust. Stress release during deglaciation can trigger large-magnitude earthquakes, as indicated by surface faults in northern Europe. Although glacially-induced stresses have been analyzed in northern Europe, they have not yet been analyzed for Greenland. We know that the Greenland Ice Sheet experienced a large melting [...]
Crustal structure of Sri Lanka derived from joint inversion of surface wave dispersion and receiver functions using a Bayesian approach
Published: 2019-10-31
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We study the crustal structure of Sri Lanka by analyzing data from a temporary seismic network deployed in 2016--2017 to shed light on the amalgamation process from a geophysical perspective. Rayleigh wave phase dispersion curves from ambient noise cross-correlation and receiver functions were jointly inverted using a transdimensional Bayesian approach. The Moho depths in Sri Lanka range between [...]