Preprints
Filtering by Subject: Physical Sciences and Mathematics
The formation and evolution of Earth’s inner core.
Published: 2024-09-03
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Growth of the inner core provides crucial power for generating the geomagnetic field and preserves a unique record of deep Earth evolution. The classical picture of inner core growth ignores the fact that the liquid core must have been supercooled below its melting temperature to spontaneously freeze the inner core. In this review we assess the impact of supercooling on inner core formation, [...]
Investigating Rayleigh wave anisotropy in faulted media with three-component beamforming: insights from numerical models and applications for geothermal exploration
Published: 2024-09-03
Subjects: Physical Sciences and Mathematics
Rayleigh waves are prevalent in the ambient seismic noise wavefield and are thus often exploited in passive seismic methods to characterise the near subsurface. In fractured or faulted media, Rayleigh waves show azimuthal anisotropy that could provide information on the fault properties. However, the exact relationship between Rayleigh wave anisotropy and true anisotropic structures is not well [...]
Signal-to-noise errors in early winter Euro-Atlantic predictions caused by weak ENSO teleconnections and pervasive North Atlantic jet biases
Published: 2024-09-03
Subjects: Atmospheric Sciences, Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Long-range winter predictions over the Euro-Atlantic sector have demonstrated significant skill but suffer from systematic signal-to-noise errors. In this study we examine early winter seasonal predictability in 16 state-of-the-art seasonal forecasting systems. Models demonstrate skill in the hindcasts of the large-scale atmospheric circulation in early winter, which mostly projects onto the East [...]
Understanding the Importance of Stellar Birth and Evolution for a Comprehensive Understanding of the Sun and Other Stars
Published: 2024-09-02
Subjects: Physical Sciences and Mathematics
Stars are massive, luminous celestial bodies that are primarily composed of hydrogen and helium gas, as well as other trace elements. Considered as the building blocks of galaxies, including our own Milky Way, and play a crucial role in the formation and evolution of the universe. In the context of the solar system, the Sun is the most important star. It is the center of the solar system, around [...]
Earlier streamflow in a snow-dwindling world
Published: 2024-09-02
Subjects: Physical Sciences and Mathematics
Impacts of climate change on water resources tend to be significant in regions where streamflow is substantially sourced as snowmelt from snowpacks1,2. In these areas, as the climate warms and the fraction of precipitation falling as snow (snow fraction, f_s) shrinks, streamflow is generally shifting toward earlier in the year by way of earlier snowmelt and increased proportional rainfall1,3,4. [...]
A 40-Year Remote Sensing Analysis of Spatiotemporal Temperature and Rainfall Patterns in Senegal
Published: 2024-08-31
Subjects: Environmental Sciences, Physical Sciences and Mathematics
Climate change impacts manifest differently worldwide, with many African countries, including Senegal, being particularly vulnerable. The decline in ground observations and limited access to these observations continue to impede research efforts to understand, plan, and mitigate the current and future impacts of climate change. This occurs at a time of rapid growth in Earth observations (EO) [...]
Were the Newdigate Earthquakes, Southern England, of 2018-2019 triggered by oil extraction?
Published: 2024-08-30
Subjects: Physical Sciences and Mathematics
The ability to attribute earthquakes to specific causes is challenging. The 2018-2019 earthquake swarm in Newdigate, Surrey, Southern England, coincides with local oil extraction at Horse Hill. Nevertheless, it remains debated whether these earthquakes were triggered by oil extraction or whether they were coincidental. Due to the onset of seismic activity before major oil extraction and the lack [...]
Simultaneous deformation along the Main Ethiopian Rift and associated transversal lineaments: an analogue modelling perspective
Published: 2024-08-29
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The interaction between the NE-SW striking Main Ethiopian Rift (MER) and the E-W oriented Yerrer-Tullu Wellel Volcano-tectonic lineament (YTVL) represents one of the least understood tectonic problems in the East African Rift System. Despite the numerous studies that have been conducted in the region, the following questions still remain to be answered: did the MER and YTVL evolve simultaneously? [...]
Physical Mechanisms of Earthquake Nucleation and Foreshocks: Cascade Triggering, Aseismic Slip, or Fluid Flows?
Published: 2024-08-29
Subjects: Physical Sciences and Mathematics
Earthquakes are caused by the rapid rupture of their seismogenic faults. Whether large or small, there is inevitably a certain nucleation process involved before the dynamic rupture. At the same time, although not very common, significant foreshock activity has been observed before some large earthquakes. Understanding the nucleation process and foreshocks of earthquakes, especially large [...]
Towards a widely applicable earthquake detection algorithm for fibreoptic and hybrid fibreoptic-seismometer networks
Published: 2024-08-29
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Distributed Acoustic Sensing (DAS) is a promising technology for providing dense (metre-scale) sampling of the seismic wavefield. However, harnessing this potential for earthquake detection with accurate phase picking and associated localisation remains challenging. Single-channel algorithms are limited by individual channel noise, while machine learning and semblance methods are typically [...]
Two-dimensional Ekman-Inertial Instability: A comparison with Inertial Instability
Published: 2024-08-29
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
In the ocean, submesoscale flows tend to undergo several hydrodynamic instabilities. In particular, Inertial Instability (InI) and Ekman-Inertial Instability (EII) are known to develop in geostrophically balanced barotropic flows whose lateral shear is larger in magnitude and opposite in sign to the Coriolis parameter. Although these instabilities share some elements, their dynamical nature can [...]
Two-layer formulation for long-runout turbidity currents: theory and bypass flow case
Published: 2024-08-28
Subjects: Engineering, Physical Sciences and Mathematics
Turbidity currents, which are stratified, sediment-laden bottom flows in the ocean or lakes, can run out for 100's to 1000's of kilometers in submarine channels without losing their stratified structure. Here we derive a layer-averaged, two-layer model for turbidity currents, specifically designed to capture long-runout. Previous models have captured runout only 10’s of kilometers, beyond which [...]
Rupture Dynamics and Near-Fault Ground Motion of the Mw7.8 Kahramanmaraş, Turkey earthquake of February 6, 2023
Published: 2024-08-28
Subjects: Physical Sciences and Mathematics
We studied the dynamic rupture propagation of the February 6th, 2023 (Mw7.8, 01:17 UTC) Pazarcık (Kahramanmaraş), Turkey, earthquake by incorporating the non-planar fault structure, the regional stress field, and a data-driven friction parameterization into numerical simulations. To explain the rupture extent of 200 km and the average speed, a regional non-uniform load is necessary and was [...]
Localized west-dipping seismic structure defines the Elgin-Lugoff Swarm Sequence in South Carolina
Published: 2024-08-28
Subjects: Education, Physical Sciences and Mathematics
An unusual earthquake swarm began in December 2021 between the towns of Elgin and Lugoff in South Carolina, United States. This area is characterized by historically low seismicity, but by April 2024 it has experienced 97 small earthquakes listed in the USGS catalog, presenting a unique opportunity to investigate the dynamics of earthquake swarms in stable continental regions. These events are [...]
Distinct roles for precession, obliquity and eccentricity in 100kyr glacial cycles
Published: 2024-08-27
Subjects: Physical Sciences and Mathematics
Attempts to discriminate between the specific roles of precession, obliquity and eccentricity in glacial/interglacial transitions have been hindered by imprecise age control. We circumvent this problem by focussing on the morphology of deglaciation/termination, which we show depends strongly on the relative phasing of precession versus obliquity. We demonstrate that while both parameters are [...]