Preprints
Filtering by Subject: Geology
Improving Urban Seismic Risk Estimates for Bishkek, Kyrgyzstan, Incorporating Recent Geological Knowledge of Hazards
Published: 2021-12-07
Subjects: Geology, Geomorphology, Tectonics and Structure
Many cities are built on or near active faults, which pose seismic hazard and risk to the urban population. This risk is exacerbated by city expansion, which may obscure signs of active faulting. Here we estimate the risk to Bishkek city, Kyrgyzstan, due to realistic earthquake scenarios based on historic earthquakes in the region and improved knowledge of the active faulting. We use previous [...]
Developing an internally consistent methodology for K-feldspar MAAD TL thermochronology
Published: 2021-12-06
Subjects: Geology
Luminescence thermochronology and thermometry can quantify recent changes in rock exhumation rates and rock surface temperatures, but these methods require accurate determination of several kinetic parameters. For K-feldspar thermoluminescence (TL) glow curves, which comprise overlapping signals of different thermal stability, it is challenging to develop measurements that capture these parameter [...]
Evaluating essential features of proppant transport at engineering scales combining field measurements with machine learning algorithms
Published: 2021-12-06
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Geology, Hydraulic Engineering, Oil, Gas, and Energy, Sustainability
The characterization of the proppant transport at a field-engineering scale is still challenging due to the lack of direct subsurface measurements. Features that control the proppant transport may link the experimental and numerical observations to the practical operations at a field scale. To improve the numerical and laboratory simulations, we propose a machine-learning-based workflow to [...]
Can machine learning improve carbon storage? Synergies of deep learning, uncertainty quantification and intelligent process control
Published: 2021-12-02
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Sustainability
As we transition from fossil fuel to renewable energy, negative emission technologies, such ascarbon capture and storage (CCS), can help us reduce CO2 emissions. Effective CO2 storage requires: (1) detailed site characterization, (2) regular, integrated risk assessment, and (3) flexible design and operation. We believe that recent advances in machine learning coupled with uncertainty [...]
Shallow depth, substantial change: fluid-metasomatism causes major compositional modifications of subducted volcanics (Mariana forearc)
Published: 2021-12-02
Subjects: Earth Sciences, Geochemistry, Geology
Mass transfer at shallow subduction levels and its ramifications for deeper processes remain incompletely constrained. New insights are provided by ocean island basalt (OIB) clasts from the Mariana forearc that experienced subduction to up to ~25–30 km depth and up to blueschist-facies metamorphism; thereafter, the clasts were recycled to the forearc seafloor via serpentinite mud volcanism. We [...]
Estuarine-deltaic controls on coastal carbon burial in the western Ganges-Brahmaputra delta over the last 5,000 years
Published: 2021-11-26
Subjects: Applied Statistics, Biogeochemistry, Earth Sciences, Environmental Sciences, Geochemistry, Geology, Geomorphology, Other Earth Sciences, Other Environmental Sciences, Other Statistics and Probability, Physical Sciences and Mathematics, Sedimentology, Statistical Methodology, Statistical Models, Statistics and Probability, Water Resource Management
The Ganges–Brahmaputra fluvial system drains the Himalayas and is one of the largest sources of terrestrial biosphere carbon to the ocean. It represents a major continental reservoir of CO2 associated with c. 1–2 billion tons of sediment transported each year. Shallow coastal environments receive substantial inputs of terrestrial carbon (900 Tg C yr−1), with allochthonous carbon capture on [...]
Variety of the drift pumice clasts from the 2021 Fukutoku-Oka-no-Ba eruption, Japan.
Published: 2021-11-25
Subjects: Geology, Volcanology
Pumice rafts that arrived at the Nansei Islands, Japan, provided a unique opportunity to investigate the Fukutoku-Oka-no-Ba (FOB) eruption of August 2021. Despite drifting for 2 months for ~1300 km, the drift pumice raft had a large volume and contained a variety of pumice clasts, some of which were deposited during a high tide in a typhoon, while others were washed up on a sandy beach. Most of [...]
The Influence of Grain Shape and Size on the Relationship Between Porosity and Permeability in Sandstone
Published: 2021-11-18
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology
An accurate and reliable description of the relationship between porosity and permeability in geological materials is valuable in understanding subsurface fluid movement. This is of great importance for studies of reservoir characterisation, useful for energy exploitation, carbon capture, use and storage (CCUS) and groundwater contamination and remediation. Whilst the relationship between pore [...]
Geochemical variability as an indicator for large volume eruptions in volcanic arcs
Published: 2021-11-17
Subjects: Earth Sciences, Geochemistry, Geology, Volcanology
Caldera-forming eruptions have the potential to impact global climate and induce drastic socioeconomic change. However, the criteria to identify volcanoes capable of producing large magnitude eruptions in the future are not well constrained. Here we compile and analyse data, revealing that volcanoes which have produced catastrophic caldera-forming eruptions in the past, typically show larger [...]
An optimization method for paleomagnetic Euler pole analysis
Published: 2021-11-15
Subjects: Geology, Geophysics and Seismology
Owing to the axial symmetry of the Earth’s magnetic field, paleomagnetic data only directly record the latitudinal and azimuthal positions of crustal blocks in the past, and paleolongitude cannot be constrained. An ability to overcome this obstacle is thus of fundamental importance to paleogeographic reconstruction. Paleomagnetic Euler pole (PEP) analysis presents a unique means to recover such [...]
Rare allanite in granulitised eclogites constrains timing of eclogite to granulite facies transition in the Bhutan Himalaya
Published: 2021-11-15
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Tectonics and Structure
During continental collision, crustal rocks are buried, deformed, transformed and exhumed. The rates, timescales and tectonic implications of these processes are determined by linking geochemical, geochronological and microstructural data from metamorphic rock-forming and accessory minerals. Exposures of lower orogenic crust provide important insights into orogenic evolution, but are rare in [...]
Plagioclase archives of depleted melts in the oceanic crust
Published: 2021-11-15
Subjects: Geochemistry, Geology
Mid-ocean ridge and ocean island basalts provide vital but incomplete insights into mantle chemistry. For example, high-anorthite plagioclase is generally too refractory and incompatible-element depleted to have crystallized from the melts that carry it to the surface. Moreover, erupted basalts rarely preserve the extreme isotopic and incompatible-element depletions found in some primitive melt [...]
Streamlined subglacial bedform sensitivity to bed characteristics across the deglaciated Northern Hemisphere
Published: 2021-11-10
Subjects: Earth Sciences, Geology, Geomorphology, Glaciology
Streamlined subglacial bedforms observed in deglaciated landscapes provide the opportunity to assess the sensitivity of glacier dynamics to bed characteristics across broader spatiotemporal scales than is possible for contemporary glacial systems. While many studies of streamlined subglacial bedforms rely on manual mapping and qualitative (i.e., visual) assessment, we semi-automatically identify [...]
Nonlinear time series analysis of palaeoclimate proxy records
Published: 2021-11-08
Subjects: Applied Statistics, Climate, Dynamic Systems, Earth Sciences, Geology, Longitudinal Data Analysis and Time Series, Multivariate Analysis, Non-linear Dynamics, Physical Sciences and Mathematics, Sedimentology, Statistical, Nonlinear, and Soft Matter Physics
Identifying and characterising dynamical regime shifts, critical transitions or potential tipping points in palaeoclimate time series is relevant for improving the understanding of often highly nonlinear Earth system dynamics. Beyond linear changes in time series properties such as mean, variance, or trend, these nonlinear regime shifts can manifest as changes in signal predictability, [...]
Subsurface temperature from seismic reflections: application to the post break up sequence offshore Namibia
Published: 2021-11-05
Subjects: Earth Sciences, Geology, Geophysics and Seismology
Accurate estimations of present-day subsurface temperatures are of critical importance to the energy industry, in particular with regards to geothermal energy and petroleum exploration. In frontier basins, the subsurface temperature regime can give an indication of the hydrocarbon potential of source horizons. The Lüderitz Basin, offshore Namibia, is a frontier deep water basin located on a [...]