Preprints
There are 5072 Preprints listed.
Seismic stratigraphy of the Guinea Plateau before, during and after the opening of the Equatorial Atlantic Gateway
Published: 2024-01-18
Subjects: Physical Sciences and Mathematics
The Guinea Plateau contains a ~200-million-year stratigraphic record, encompassing the mid-Cretaceous opening of the Equatorial Atlantic Gateway (EAG). Here we present new 2D seismic data to constrain the structural and stratigraphic evolution of the plateau. Seismic stratigraphic analysis reveals five megasequences of ~25-65 My duration: M1, a Jurassic syn-rift sequence with prominent [...]
Stones that tell stories
Published: 2024-01-18
Subjects: Education, Engineering
When a historical building, monument, or cultural heritage artifact is affected by a natural or anthropic event, the first reaction is to recover and restore them to maintain our heritage for the next generations. If they are made of stone, some are completely destroyed, but it is often still possible to recognize the facts that made them a cultural item. In many cases, the marks of violent [...]
A new structure determination of the magnesium phosphate mineral struvite (MgNH4PO4· 6H2O) at 100 K
Published: 2024-01-17
Subjects: Other Earth Sciences, Physical Sciences and Mathematics
The magnesium phosphate mineral struvite (MgNH4PO4·6H2O) is of interest for the recovery of phosphorus from wastewaters and for use as a fertilizer in agriculture, yet its structure is still debated. The structure of synthetic single crystals of struvite was characterized through refinement of a single-crystal X-ray diffraction pattern acquired at 100 K with the positions of all hydrogen atoms [...]
Assessment of Hydrochemistry and Groundwater Quality in Ijokodo and It’s Environment, Ibadan, Nigeria
Published: 2024-01-17
Subjects: Physical Sciences and Mathematics
The study area occurs within the Precambrian basement complex composed of quartzite, quartz-schist, biotite-andbiotite-hornblende-gneiss (migmatite) as the main rock units. Physiochemical assessment of shallow groundwater in Ijokodo area was carried out to determine its suitability for drinking and irrigation purposes. Thirteen (13) groundwater samples were collected and subjected field [...]
The Effects of Characteristic Slip Distance on Earthquake Nucleation Styles in Fully Dynamic Seismic Cycle Simulations
Published: 2024-01-17
Subjects: Earth Sciences, Geophysics and Seismology
Earthquake nucleation is a crucial preparation process of the following coseismic rupture propagation. Under the framework of rate-and-state friction (RSF), it was found that the ratios of a to b parameters control whether earthquakes nucleate as an expanding crack or a fixed length. However, the characteristic slip distance DRS controls the weakening efficiency of fault strength and can [...]
Deep learning with simulated laser scanning data for 3D point cloud classification
Published: 2024-01-17
Subjects: Artificial Intelligence and Robotics, Computer Sciences, Earth Sciences, Numerical Analysis and Scientific Computing, Other Earth Sciences
Laser scanning is an active remote sensing technique applied in many disciplines to acquire state-of-the-art spatial measurements. Semantic labeling is often necessary to extract information from the raw point cloud. Deep learning methods constitute a data-hungry solution for the semantic segmentation of point clouds. In this work, we investigate the use of simulated laser scanning for training [...]
Tectonostratigraphy of the Late Neoproterozoic in the Eastern Arabian Plate – a revision of the Ediacaran geological evolution in the Central Oman Mountains (Jabal Al Akhdar, Sultanate of Oman)
Published: 2024-01-17
Subjects: Geology
In northeastern Oman, within the Neoproterozoic Huqf Supergroup, well-exposed sedimentary formations spanning the Cryogenian to Ediacaran periods, lie beneath the late Palaeozoic "Hercynian Unconformity". These rocks bear the marks of the distant Cadomian Orogeny. Among these, the youngest correspond to the diverse Ediacaran Fara Formation, a member of the Ara Group. Our study extensively [...]
Fast relocking and afterslip-seismicity evolution following the 2015 Mw 8.3 Illapel earthquake in Chile
Published: 2024-01-16
Subjects: Physical Sciences and Mathematics
Large subduction earthquakes induce complex postseismic deformation, primarily driven by afterslip and viscoelastic relaxation, in addition to interplate relocking processes. However, these signals are intricately intertwined, posing challenges in determining the timing and nature of relocking. Here, we use six years of continuous GNSS measurements (2015-2021) to study the spatio-temporal [...]
B-value variations in the Central Chile seismic gap assessed by a Bayesian transdimensional approach
Published: 2024-01-16
Subjects: Physical Sciences and Mathematics
The b-value can be used to characterize the seismic activity for a given earthquake catalog and provide information on the stress level accumulated at active faults. Here we develop an algorithm to objectively estimate variations of b-value along one arbitrary dimension. To this end, we employ a Bayesian transdimensional approach where the seismic domains will be self-defined according to [...]
Retrogressive thaw slump activity in the western Canadian Arctic (1984-2016)
Published: 2024-01-15
Subjects: Physical Sciences and Mathematics
The spatial distribution and links to climate of retrogressive thaw slump (RTS) activity over 32 years were examined using Google Earth Engine Timelapse videos for five areas in the western Canadian Arctic totalling 150 000 km2, each previously identified as having a high spatial concentration of these thermokarst landforms. Four spatial datasets run from 1984 to 2016 (Banks Island, northwest [...]
New Insights into the Structural and Stratigraphic Evolution of the Malay Basin Using 3D Seismic Data: Implications for Regional Carbon Capture and Storage Potential
Published: 2024-01-15
Subjects: Physical Sciences and Mathematics
The Malay Basin is a mature hydrocarbon province that is being re-assessed for CO2 storage. Selecting appropriate storage sites requires a comprehensive understanding of the structural and stratigraphic history of the basin, but previous studies of the basin have been limited to observations from either regional, 2D seismic lines or individual 3D seismic volumes. Here, we access and utilize a [...]
Dynamic evolution of competing same-dip double subduction: New perspectives of the Neo-Tethyan plate tectonics
Published: 2024-01-15
Subjects: Earth Sciences, Geophysics and Seismology, Tectonics and Structure
Same-dip double-subduction (SDDS) systems are widely reported from present as well as past complex convergent plate tectonic configurations. However, the dynamics of their evolution is poorly understood, which is crucial to conceptualize anomalous subducting slab kinematics and associated observed geological phenomena, such as irregular trench migration rates, high convergence velocities, and [...]
Deep Learning Improves Global Satellite Observations of Ocean Eddy Dynamics
Published: 2024-01-15
Subjects: Artificial Intelligence and Robotics, Fluid Dynamics, Oceanography and Atmospheric Sciences and Meteorology
Ocean eddies affect large-scale circulation and induce a kinetic energy cascade through their non-linear interactions. However, since global observations of eddy dynamics come from satellite altimetry maps that smooth eddies and distort their geometry, the strength of this cascade is underestimated. Here, we use deep learning to improve observational estimates of global surface geostrophic [...]
Magmatic Controls on Volcanic Sulfur Emissions at the Iceland Hotspot
Published: 2024-01-14
Subjects: Geochemistry, Geology, Volcanology
Outgassing of S (as SO2) is one of the principal hazards posed by volcanic eruptions. However, S emission potentials of most volcanoes globally are poorly constrained due to a short observational record and an incomplete understanding of the magmatic processes that influence pre-eruptive S concentrations. Here, we use a compilation of published and new data from melt inclusions—which [...]
Subtemperate regelation exhibits power-law premelting
Published: 2024-01-13
Subjects: Fluid Dynamics, Glaciology, Other Physics
Wire regelation is a common tabletop demonstration of the pressure-dependence of the ice melting temperature where loaded wires move from top to bottom through a block of ice, yet leaves the block intact. With the background temperature fixed at the bulk melting point $\sim0\,^{\circ}$C, the elevated ice and liquid pressures beneath the wire cause melting because of the negative Clapeyron slope, [...]