Preprints
There are 4725 Preprints listed.
Accelerating Numerical Wave Propagation by Wavefield Adapted Meshes, Part II: Full-Waveform Inversion
Published: 2019-08-22
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We present a novel full-waveform inversion approach which can reduce the computational cost by up to an order of magnitude compared to conventional approaches, provided that variations in medium properties are sufficiently smooth. Our method is based on the usage of wavefield-adapted meshes which accelerate the forward and adjoint wavefield simulations. By adapting the mesh to the expected [...]
Communicating with public audiences about the geological subsurface: thinking inside the box.
Published: 2019-08-21
Subjects: Earth Sciences, Physical Sciences and Mathematics, Social and Behavioral Sciences
Community concerns over resource extraction and public anxieties about insertion of waters and waste are creating a growing societal unease about geological exploitation of the subsurface. Addressing these emergent areas of socially contested subsurface geoscience is difficult for many academic and industrial geologists, not least because translating unfamiliar concepts of the geological [...]
Collapse of Eurasian ice sheets 14,600 years ago was a major source of global Meltwater Pulse 1a
Published: 2019-08-21
Subjects: Climate, Earth Sciences, Environmental Sciences, Geology, Glaciology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Rapid sea-level rise caused by the collapse of large ice sheets is a global threat to human societies. In the last deglacial period, the rate of global sea-level rise peaked at more than 4 cm/yr during Meltwater Pulse 1a, which coincided with the abrupt Bølling warming event 14,650 yr ago. However, the sources of the meltwater have proven elusive, and the contribution from Eurasian ice sheets has [...]
What Fractionates Oxygen Isotopes During Respiration? Insights from Multiple Isotopologues and Theory
Published: 2019-08-21
Subjects: Biogeochemistry, Earth Sciences, Physical Sciences and Mathematics
The precise mass dependence of respiratory O2 consumption underpins the “oxygen triple-isotope” approach to quantifying gross primary productivity in modern and ancient environments. Yet, the physical-chemical origins of the key 18O/16O and 17O/16O covariations observed during respiration have not been tied to theory; thus the approach remains empirical. First-principles calculations on enzyme [...]
The anelasticity of zinc and its implications for the Earth’s inner core
Published: 2019-08-21
Subjects: Earth Sciences, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics
The Earth’s inner core exhibits significant anisotropy in both seismic velocity and attenuation as well as hemispherical and depth variations. These observations point to an inner core that is both complex and dynamic. However, interpretation of these observations without knowledge of the attenuation processes active in the inner-core is difficult. To address this we have used zinc, as a [...]
Quantifying Eulerian Eddy Leakiness in An Idealized Model
Published: 2019-08-21
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
An idealized eddy-resolving ocean basin, closely resembling the North Pacific ocean, is simulated using MITgcm. We identify rotationally coherent Lagrangian vortices (RCLVs) and sea surface height (SSH) eddies based on the Lagrangian and Eulerian framework, respectively. General statistical results show that RCLVs have a much smaller coherent core than SSH eddies with the ratio of radius is about [...]
Shifting velocity of temperature extremes under climate change
Published: 2019-08-19
Subjects: Climate, Environmental Indicators and Impact Assessment, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Rapid changes in climatic conditions threaten both socioeconomic and ecological systems, as these might not be able to adapt or to migrate at the same pace as that of global warming. In particular, an increase of weather and climate extremes can lead to increased stress on human and natural systems, and a tendency for serious adverse effects. Relying on the EURO-CORDEX simulations, we compare the [...]
Influence of floods, tides, and vegetation on sediment retention in Wax Lake Delta, LA, USA
Published: 2019-08-19
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
Sediment is the most valuable natural resource for deltaic environments, and to build new land sediment must be retained in the delta instead of being transported offshore. Despite this, we do not know what controls sediment retention within a delta. Here we use a calibrated numerical model of Wax Lake Delta, LA, USA to analyze sediment retention for different flood-wave magnitudes, tidal [...]
Review paper: The 2nd June 1979 Mw 6.1 Cadoux surface rupturing earthquake, Australia
Published: 2019-08-17
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
The 2nd June 1979 moment magnitude (Mw) 6.1 Cadoux earthquake caused a complex, multi-fault surface rupture consisting of six mapped scarps: (from south to north) the 8 km long west dipping Robb scarp, 3 km long south dipping Cumming scarp, the Lone Tree, Carter and Tank scarps (which together define an east-dipping arcuate rupture) and the 2.5 km long southwest-dipping Kalajzic scarp. Surface [...]
Review paper: The 10th March 1970 Mw 5.0 Calingiri surface rupturing earthquake, Australia
Published: 2019-08-17
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
The 10th March 1970 moment magnitude (Mw) 5.0 Calingiri earthquake surface rupture is 3.3 km long with a maximum vertical displacement of 0.4 m. The fault as defined by surface measurements is a shallow-dipping reverse fault (~ 20° east) with a probable shallow hypocentre (< 1 km). This is consistent with published hypocentral depths, though large uncertainties exist within the seismological [...]
Review paper: The 30th March 1986 Mw 5.7 Marryat Creek surface rupturing earthquake, Australia
Published: 2019-08-17
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
The 30th March 1986 Mw 5.7 Marryat Creek earthquake produced a highly arcuate 13 km long surface rupture with maximum vertical displacement of 0.9 m. Sinistral displacement on the NE-SW limb, dextral displacement on the NNE-SSW limb, and maximum vertical displacement in the central apex of rupture supports SW over NE movement of a hanging-wall block. Epicentre locations are poorly constrained and [...]
Review paper: The 14th October 1968 Mw 6.6 Meckering surface rupturing earthquake, Australia
Published: 2019-08-17
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
The 14th October 1968 MW 6.6 Meckering earthquake surface rupture is comprised of a main 37 km long concave Meckering scarp (with a 1.5 km wide dextral step-over along the Burges en-echelon rupture complex) and a minor 9 km long rupture on the Meckering scarp foot-wall (the Splinter scarp, also with a 1.5 km dextral step-over). We recommend a total surface rupture length of 44.4 km for [...]
Review paper: The 20th May 2016 Mw 6.1 Petermann surface rupturing earthquake, Australia
Published: 2019-08-17
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
The 20th May 2016 Mw 6.1 Petermann earthquake produced a 21 km long surface rupture with a maximum vertical offset of 0.9 m. Geological and geophysical data provide strong evidence that rupture occurred along a mylonite foliation plane with an orientation defined by deformation from the nearby Woodroffe Thrust, a major Neoproterozoic terrane suture. The most geologically and seismologically [...]
Review paper: The 23rd March 2012 Mw 5.2 Pukatja surface rupturing earthquake, Australia
Published: 2019-08-17
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
The 23rd March 2012 Mw 5.2 Pukatja earthquake produced an arcuate surface rupture 1.6 km long with a maximum vertical offset of 0.48 m. We reclassify its length to 1 km based on application of orientation and kinematic criteria used previously to measure other historic Australian surface ruptures. Epicentres are poorly constrained and inaccurate, located up to 17 km from the surface rupture with [...]
Frozen fringe explains sediment freeze-on during Heinrich events
Published: 2019-08-16
Subjects: Applied Mathematics, Earth Sciences, Glaciology, Physical Sciences and Mathematics
Anomalous coarse-grained sediment layers beneath the North Atlantic likely originated from sediment freeze-on to the base of ice sheets during the last glacial period. These layers represent periods of extreme ice discharge, called Heinrich events, and are variously attributed to ice stream flow instability, ice shelf collapse, or enhanced terminus melting due to ocean warming. In this paper, we [...]