Preprints
Filtering by Subject: Earth Sciences
Dislocation interactions during low-temperature plasticity of olivine strengthen the lithospheric mantle
Published: 2019-09-21
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
The strength of the lithosphere is typically modelled based on constitutive equations for steady-state flow. However, models of lithospheric flexure reveal differences in lithospheric strength that are difficult to reconcile based on such flow laws. Recent rheological data from low-temperature deformation experiments on olivine suggest that this discrepancy may be largely explained by strain [...]
NSB: an expanded and improved database of marine planktonic microfossil data and deep-sea stratigraphy
Published: 2019-09-19
Subjects: Computer Sciences, Databases and Information Systems, Earth Sciences, Paleontology, Physical Sciences and Mathematics, Stratigraphy
Thirty years ago, the Neptune Database was created to synthesize microfossil occurrences from the deep-sea drilling record. It has been used in numerous studies by both biologists and paleontologists of the evolution and distribution in space and time of marine microplankton. After decades of discontinuous development in various institutions, a significant overhaul of the system was made during [...]
Global groundwater sustainability, resources and systems in the Anthropocene
Published: 2019-09-19
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
Groundwater is a crucial resource for current and future generations but is not being sustainably used in many parts of the world. The objective of this review is to provide a clear portrait of global-scale groundwater sustainability, systems and resources in the Anthropocene, in order to inspire a pivot towards more sustainable pathways. We examine groundwater from three different but related [...]
The influence of local low-density basement anomalies on the distribution of fluvio-deltaic sediment in rift basins: the early Carboniferous Fell Sandstone Formation, northern England
Published: 2019-09-17
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Tectonics and Structure
Local low-density basement anomalies are an important part of a rift basin’s inherited structural framework that can influence basin stratigraphy. Large granitic intrusions can cause local alterations in the basement’s density and often spatially correlate with fault-bounded highs (blocks) or convex-shaped regional flexural highs due to their isostatic responses. We investigate the influence of [...]
Weak phases production and heat generation controls fault friction during seismic slip
Published: 2019-09-15
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The triggering and magnitude of earthquakes is determined by the friction evolution along faults. Experimental results have revealed a drastic decrease of the friction coefficient for velocities close to the maximum seismic one, independently of the material studied. Due to the extreme loading conditions during seismic slip, many competing physical phenomena are occurring (like mineral [...]
Miniature paleo-speleothems from the earliest Ediacaran (635 Ma) Doushantuo cap dolostone in South China and their implications for terrestrial ecosystems
Published: 2019-09-15
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology, Speleology, Stratigraphy
Speleothems can offer insights into terrestrial life because their formation is critically dependent on soil-microbial ecosystems. Here we report the wide distribution of miniature paleo-speleothems from the ~635 Ma Doushantuo cap dolostone in South China in order to understand the recovery of terrestrial life after the terminal Cryogenian Marinoan snowball Earth glaciation. The cap dolostone was [...]
Infilling abandoned deltaic channels through tidal sedimentation: a case study from the Huanghe (Yellow River) delta, China
Published: 2019-09-11
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
Upon avulsion, abandoned deltaic distributary channels receives water and sediment delivered by a tie channel, overbank flow, and by tidal inundation from the receiving basin. The transport and deposition of sediment arising from this latter input have important impacts on delta development, yet are not well-constrained from field observations or numerical models. Herein, the Huanghe (Yellow [...]
Coseismic or Landslide? The source of the 2018 Palu Tsunami
Published: 2019-09-10
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
On 28 September, 2018, Indonesia was struck by a MW 7.5 strike-slip earthquake. An unexpected tsunami followed, inundating nearby coastlines leading to extensive damage. Given the traditionally non-tsunamigenic mechanism, it is important to ascertain if the source of the tsunami is indeed from coseismic deformation, or something else, such as shaking induced landsliding. Here we determine the [...]
A report on gender diversity and equality at Tectonic Studies Group (TSG) meetings: 2007-2019.
Published: 2019-09-10
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The Tectonic Studies Group (TSG) is a specialist group of the Geological Society of London that was founded in 1970 as a forum for discussion of research in structural geology and tectonics. Here, we report on gender diversity and equality at the TSG annual conferences between 2007 and 2019. Gender diversity was analysed in the following categories: 1.) talks presented; 2.) posters presented; 3.) [...]
Modeling deltaic lobe-building cycles and channel avulsions for the Yellow River delta, China
Published: 2019-09-10
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
River deltas grow by repeating cycles of lobe development punctuated by channel avulsions, so that over time, lobes amalgamate to produce a composite landform. Existing models have shown that backwater hydrodynamics are important in avulsion dynamics, but the effect of lobe progradation on avulsion frequency and location has yet to be explored. Herein, a quasi-2D numerical model incorporating [...]
Bayesian elastic Full-Waveform Inversion using Hamiltonian Monte Carlo
Published: 2019-09-09
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We present a proof of concept for Bayesian elastic full-waveform inversion in 2-D. This is based on (1) Hamiltonian Monte Carlo sampling of the posterior distribution, (2) the computation of misfit derivatives using adjoint techniques, and (3) a mass matrix tuning of the Hamiltonian Monte Carlo algorithm that accounts for the different sensitivities of seismic velocities and density. We apply our [...]
Paradoxical impact of sprawling intra-Urban Heat Islets: Reducing mean surface temperatures while enhancing local extremes
Published: 2019-09-09
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Life Sciences, Physical Sciences and Mathematics, Statistics and Probability
Cities are at the forefront of climate change impacts and face a growing burden of adaptation to ensuing natural hazards. Extreme heat is a particularly challenging hazard as persistent heatwaves are locally exacerbated by the Urban Heat Island (UHI) effect. As a result, there is an increasing scientific interest in the influence of diverse urban morphologies on UHI. However, as the temperatures [...]
Recommended "Best Practices" for Chirp Acquisition and Processing
Published: 2019-09-09
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
This BOEM report describes details our experience/lessons learned in chirp subbottom data collection and processing.
Investigating global correlations between tsunami, earthquake, and subduction zone characteristics
Published: 2019-09-09
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Tsunamigenic earthquakes pose a large hazard in subduction zones, but it is currently unclear in which - if any - tectonic setting they preferentially occur. Here, we compile the global Subduction Nature & Interconnected Tsunamigenic earthquake Characteristics (SNITCH) database with parameters on subduction geometry and tectonics, megathrust seismicity, and tsunami characteristics of tsunamis [...]
Methods and Test Cases for Linking Physics-Based Earthquake and Tsunami Models
Published: 2019-09-06
Subjects: Computer Sciences, Earth Sciences, Geology, Geophysics and Seismology, Other Computer Sciences, Physical Sciences and Mathematics
Despite the inter-dependence of long term deformation, earthquakes and tsunamis, few modelling approaches bridge these processes. To advance the understanding of tsunami generation and earthquake-tsunami interactions, we present new methods for linking physics-based models of subduction zone geodynamics and seismic cycling, three-dimensional dynamic earthquake rupture, and tsunami generation, [...]