Preprints
Filtering by Subject: Earth Sciences
A mixed $RT_0 - P_0$ Raviart-Thomas finite element implementation of Darcy Equation in GNU Octave
Published: 2020-04-14
Subjects: Applied Mathematics, Bioresource and Agricultural Engineering, Chemical Engineering, Computational Engineering, Earth Sciences, Engineering, Environmental Sciences, Hydrology, Numerical Analysis and Computation, Partial Differential Equations, Physical Sciences and Mathematics, Water Resource Management
In this paper we shall describe mixed formulations -differential and variational- of Darcys flow equation, an important model of elliptic problem. We describe * Galerkin method with finite dimensional spaces; * Local matrices and assembling; * Raviart-Thomas $RT_0 - P_0$ elements; * Edge basis and local matrices for $RT_0 - P_0$ FEM; * Model problem with corresponding local matrices, right hand [...]
SymAE: an autoencoder with embedded physical symmetries for passive time-lapse monitoring
Published: 2020-04-14
Subjects: Applied Mathematics, Computer Sciences, Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We introduce SymAE, an auto-encoder architecture that learns to separate multichannel passive-seismic datasets into qualitatively interpretable components: one component corresponds to path-specific effects associated with subsurface properties while the other component corresponds to the spectral signature of the passive sources. This information is represented by two latent codes produced by [...]
Success at the farm-level in payments for ecosystem services: monetary incentives, participatory processes and institutional adaptation all matter
Published: 2020-04-14
Subjects: Earth Sciences, Environmental Sciences, Life Sciences, Natural Resources and Conservation, Physical Sciences and Mathematics
While payments for ecosystem services (PES) schemes are increasingly common, in most cases, their effectiveness has lagged behind initial expectations. A major debate exists around whether performance can be improved by prioritising project design features that align with the theoretical, economistic model of PES, or whether, where necessary, it is more important for projects to depart from this [...]
Weak influence of paleoenvironmental conditions on the subsurface biosphere of lake Ohrid in the last 515 ka
Published: 2020-04-14
Subjects: Earth Sciences, Environmental Microbiology and Microbial Ecology Life Sciences, Environmental Sciences, Life Sciences, Microbiology, Other Earth Sciences, Paleobiology, Physical Sciences and Mathematics
Understanding the response of geo- and biosystems to past climatic disturbance is primordial to assess the short to long terms effects of current global change. Lacustrine sediments are commonly used to investigate the impact of climatic change on biogeochemical cycling. In these sediments, subsurface microbial communities play a primordial role in nutrient, organic matter and elemental cycling, [...]
Global heat uptake by inland waters
Published: 2020-04-13
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
Heat uptake is a key variable for understanding the Earth system response to greenhouse gas forcing. Despite the importance of this heat budget, heat uptake by inland waters has so far not been quanti?ed. Here we use a unique combination of global-scale lake models, global hydrological models and Earth system models to quantify global heat up take by natural lakes, reservoirs and rivers. The [...]
A new approach to inferring basal drag and ice rheology in ice streams, with applications to West Antarctic ice streams
Published: 2020-04-13
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Drag at the bed and along the lateral margins are the primary forces resisting flow in outlet glaciers. Simultaneously inferring these parame- ters is challenging since basal drag and ice viscosity are coupled in the momen- tum balance, which governs ice flow. Here, we test the ability of adjoint-based inverse methods to infer the slipperiness coefficient in a power-law sliding law and the [...]
Aquifer deformation and active faulting in Salt Lake Valley, Utah, USA
Published: 2020-04-13
Subjects: Earth Sciences, Geophysics and Seismology, Hydrology, Physical Sciences and Mathematics
Aquifers and fault zones may interact through groundwater flow and stress redistribution, yet their spatiotemporal relationship remains enigmatic. Here we quantify changes in water storage and associated stress along the Wasatch Fault Zone in Salt Lake Valley, recently shaken by a M5.7 earthquake on March 18th, 2020. Ground deformation mapped by Sentinel-1 SAR imagery (2014-2019) reveals an [...]
InSAR Time Series Analysis of L-band Wide- Swath SAR Data Acquired by ALOS-2
Published: 2020-04-13
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Environmental Sciences, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Operating at L-band (~24 cm wavelength) in wide-swath modes is one of the characteristics of the new and next generation satellite synthetic aperture radar (SAR) missions. After 3 years of operation, the Japan Aerospace Exploration Agency Advanced Land Observing Satellite-2 (ALOS-2) satellite has acquired a wealth of L-band wide-swath SAR data over many areas using its ScanSAR mode. We present [...]
Fault seal modelling – the influence of fluid properties on fault sealing capacity in hydrocarbon and CO2 systems
Published: 2020-04-13
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Fault seal analysis is a key part of understanding the hydrocarbon trapping mechanisms in the petroleum industry. Fault seal research has also been expanded to CO2-brine systems for the application to Carbon Capture and Storage (CCS). The wetting properties of rock-forming minerals in the presence of hydrocarbons or CO2 are a source of uncertainty in the calculations of capillary threshold [...]
Turbidites, Topography and Tectonics: Evolution of submarine channel-lobe systems in the salt-influenced Kwanza Basin, offshore Angola
Published: 2020-04-07
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology
Understanding the evolution of submarine channel-lobe systems on salt-influenced slopes is challenging as systems react to seemingly subtle changes in sea-floor topography. The impact of large blocking structures on individual deep-water systems is well documented, but understanding of the spatio-temporal evolution of regionally extensive channel-lobe systems in areas containing modest salt [...]
Seismic electric signals (SES) and earthquakes: A review of an updated VAN method and competing hypotheses for SES generation and earthquake triggering
Published: 2020-04-07
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Studies, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Planetary Geophysics and Seismology, Planetary Sciences, Social and Behavioral Sciences
Electromagnetic phenomena are sometimes associated with seismic events, but earthquake prediction using seismic electric signals (SES) has not been seriously considered since the early 1990s. There are several causes: (1) false alarms that have created panics in Greece, and (2) a strong critique of the Varotsos-Alexopoulos-Nomicos (VAN) method used there. An updated VAN method that includes time [...]
Is the Aftershock Zone Area a Good Proxy for the Mainshock Rupture Area?
Published: 2020-04-07
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The locations of aftershocks are often observed to be on the same fault plane as the mainshock and used as proxies for its rupture area. Recent developments in earthquake relocation techniques have led to great improvements in the accuracy of earthquake locations, offering an unprecedented opportunity to quantify both the aftershock distribution and mainshock rupture area. In this study, we [...]
Measuring Azimuth Deformation With L-Band ALOS-2 ScanSAR Interferometry
Published: 2020-04-07
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Computational Engineering, Computer Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Signal Processing, Tectonics and Structure, Volcanology
We analyze the methods for measuring azimuth deformation with the L-band Advanced Land Observing Satellite-2 (ALOS-2) scanning synthetic aperture radar (ScanSAR) interferometry. To implement the methods, we extract focused bursts from the ALOS-2 full-aperture product, which is the only product available for ScanSAR interferometry at present. The extracted bursts are properly processed to measure [...]
Estimating Azimuth Offset With Double-Difference Interferometric Phase: The Effect of Azimuth FM Rate Error in Focusing
Published: 2020-04-06
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Environmental Sciences, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Physics, Tectonics and Structure, Volcanology
Estimating azimuth offset with double-difference interferometric (DDI) phase, which is called multiple-aperture interferometric synthetic aperture radar (InSAR) or spectral diversity, is increasingly used in recent years to measure azimuth deformation or to accurately coregister a pair of InSAR images. We analyze the effect of frequency modulation (FM) rate error in focusing on the DDI phase with [...]
Rethinking Groundwater Age
Published: 2020-04-03
Subjects: Earth Sciences, Geochemistry, Hydrology, Physical Sciences and Mathematics
The ideas that old or “fossil” groundwater cannot be pumped sustainably, or that recently recharged groundwater is inherently sustainable are both mistaken. Both old and young groundwaters can be used in physically sustainable or unsustainable ways.