Preprints
Filtering by Subject: Earth Sciences
The North American hydrologic cycle through the last deglaciation
Published: 2019-10-01
Subjects: Climate, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
While the climate evolution of North America during the last deglaciation has received considerable attention, few detailed model–data comparisons of the deglacial hydroclimate have been conducted at the continental scale. Here we use a transient climate simulation of the last deglaciation and a synthesis of hydroclimate proxies from across the continent to broadly assess the moisture budget and [...]
The fingerprints of flexure in slab seismicity
Published: 2019-10-01
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Earthquake moment tensors in east Pacific (ePac) slabs typically show downdip tensional axes (DT), whereas in the west Pacific (wPac) they typically show downdip compressional axes (DC) or have mixed orientations indicative of unbending. Prevailing conceptual models emphasise uniform stress/deformation modes, i.e. bulk stretching or shortening, as the dominant control on intermediate depth [...]
Submarine drainage distribution and main sediment transfer pathways along the Brazilian continental margin
Published: 2019-10-01
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
We mapped the main drainage systems using the available regional bathymetric grids in order to understand the canyon and channel distribution along the margin and identify the preferential pathways for sediment transfer to the nearby ocean basins
Thermal and magnetic evolution of a crystallizing basal magma ocean in Earths mantle
Published: 2019-10-01
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Planetary Geophysics and Seismology, Planetary Sciences
We present the thermochemical evolution of a downward crystallizing BMO overlying the liquid outer core and probe its capability to dissipate enough power to generate and sustain an early dynamo. A total of 61 out of 112 scenarios for a BMO with imposed, present-day $Q_{BMO}$ values of 15, 18, and 21 TW and $Q_r$ values of 4, 8, and 12 TW fully crystallized during the age of the Earth. Most of [...]
Mechanisms controlling fluid break-up and reconnection during two-phase flow in porous media
Published: 2019-10-01
Subjects: Earth Sciences, Engineering, Geophysics and Seismology, Life Sciences, Physical Sciences and Mathematics
The use of Darcys law to describe steady-state multiphase flow in porous media has been justified by the assumption that the fluids flow in continuously connected pathways. However, a range of complex interface dynamics have been observed during macroscopically steady-state flow, including intermittent pathway flow where flow pathways periodically disconnect and reconnect. The physical [...]
Machine Learning Reveals the Seismic Signature of Eruptive Behavior at Piton de la Fournaise Volcano
Published: 2019-09-30
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
Volcanic tremor is key to our understanding of active magmatic systems but, due to its complexity, there is still a debate concerning its origins and how it can be used to characterize eruptive dynamics. In this study we leverage machine learning (ML) techniques using 6 years of continuous seismic data from the Piton de la Fournaise volcano (La Réunion island) to describe specific patterns of [...]
Holocene relative sea-level changes and glacial isostatic adjustment of the U.S. Atlantic coast
Published: 2019-09-30
Subjects: Climate, Earth Sciences, Environmental Sciences, Geomorphology, Glaciology, Oceanography and Atmospheric Sciences and Meteorology, Other Earth Sciences, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure
The first quality-controlled Holocene sea-level database for the U.S. Atlantic coast has been constructed from 686 sea-level indicators. The database documents a decreasing rate of relative sea-level (RSL) rise through time with no evidence of sea level being above present in the middle to late Holocene. The highest rates of RSL rise are found in the mid-Atlantic region. We employ the database to [...]
An introduction to seismic diffraction
Published: 2019-09-30
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Despite its unique properties the diffracted seismic wavefield is still rarely exploited in common practice. Although the first works on seismic diffraction date back at least as far as the 1950s, a first rigorous theoretical framework for diffraction imaging only evolved decades later and many important questions still remain unanswered until the present day. While this comparably slow [...]
Repeated degradation and progradation of a submarine slope over geological timescales
Published: 2019-09-30
Subjects: Earth Sciences, Geology, Other Earth Sciences, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure
Submarine slopes prograde via accretion of sediment to clinoform foresets, and degrade in response to channel or canyon incision, or mass-wasting processes. The timescales over which progradation and degradation occur, and the large-scale stratigraphic record of these processes, remain unclear due poor age constraints in subsurface-based studies, and areally limited exposures of exhumed systems. [...]
Mercury loading within the Selenga River Basin and Lake Baikal, Siberia
Published: 2019-09-28
Subjects: Biogeochemistry, Earth Sciences, Environmental Sciences, Geochemistry, Physical Sciences and Mathematics
Mercury (Hg) loading in Lake Baikal, a UNESCO world heritage site, is growing and poses a serious health concern to the lake’s ecosystem due to the ability of Hg to transform into a toxic form, known as methylmercury (MeHg). Monitoring of Hg into Lake Baikal is spatially and temporally sparse, highlighting the need for insights into historic Hg loading. This study reports measurements of Hg [...]
How do deep-water volcanoes grow?
Published: 2019-09-23
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
Deep-water volcanoes are emplaced in water depths >1.0 km and are widespread along continental margins and in ocean basins. Whilst the external morphology of deep-water volcanoes can be mapped using bathymetric surveys, their internal structure and true volume remain enigmatic. It is thus difficult to determine how deep-water volcanoes grow. We investigate 13 Late Miocene-to-Quaternary, [...]
Representative elementary volumes, hysteresis and heterogeneity in multiphase flow from the pore to continuum scale
Published: 2019-09-22
Subjects: Earth Sciences, Engineering, Hydrology, Physical Sciences and Mathematics
Representative elementary volumes (REVs) and heterogeneity are key concepts in continuum multiphase flow, yet their manifestation from the pore-scale and associated impacts with the flow regime are not well understood. We use a multi-scale experimental and modelling approach to elucidate the role of REVs, hysteresis and heterogeneity in multiphase flow in two distinct water-wetting Bentheimer [...]
The Community Code Verification Exercise for Simulating Sequences of Earthquakes and Aseismic Slip (SEAS)
Published: 2019-09-21
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Numerical simulations of Sequences of Earthquakes and Aseismic Slip (SEAS) have made great progress over the past decades to address important questions in earthquake physics and fault mechanics. However, significant challenges in SEAS modeling remain in resolving multiscale interactions between aseismic fault slip, earthquake nucleation, and dynamic rupture; and understanding physical factors [...]
An image- and BET-based Monte-Carlo approach to determine mineral accessible surface areas in sandstones
Published: 2019-09-21
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics
Accessible surface areas (ASAs) of individual rock-forming minerals exert a fundamental control on how minerals react with formation fluids. However, due to lacking adequate quantification methods, determining the ASAs of specific minerals in a multi-mineral rock at the appropriate scale still remains difficult. Whole-rock Brunauer-Emmett-Teller (BET) measurements at atomic scales cannot account [...]
Controls on the development and termination of failed continental rifts: Insights from the crustal structure and rifting style of the North Sea via ambient noise tomography
Published: 2019-09-21
Subjects: Applied Mathematics, Computer Sciences, Earth Sciences, Geophysics and Seismology, Numerical Analysis and Computation, Numerical Analysis and Scientific Computing, Physical Sciences and Mathematics, Probability, Statistics and Probability
The mid to lower crust plays an important role in rift initiation and evolution, particularly when large scale sutures and/or terrane boundaries are present. These inherited features can focus strain or act as inhibitors to extensional deformation. Ancient tectonic features are known to exist beneath the iconic failed rift system of the North Sea making it the ideal location to investigate the [...]