Preprints
Filtering by Subject: Physical Sciences and Mathematics
Bayesian inference on the initiation phase of the 2014 Iquique, Chile, earthquake
Published: 2022-10-03
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We investigate the initiation phase of the 2014 Mw8.1 Iquique earthquake in northern Chile. In particular, we focus on the month preceding the mainshock, a time period known to exhibit an intensification of the seismic and aseismic activity in the region. The goal is to estimate the time-evolution and partitioning of seismic and aseismic slip during the preparatory phase of the mainshock. To do [...]
Origin, transport, accumulation of methane in sedimentary basins revisited
Published: 2022-10-02
Subjects: Physical Sciences and Mathematics
The current widely accepted models for generation of methane by thermal cracking of oil and by bacterial fermentation have several serious inconsistencies. Experiments show that high-temperature pyrolysis of liquid (C6+) hydrocarbons does not produce methane even if hydrogen is added to the feed, and condensate, which is generally assumed to be the direct precursor to methane, generally amounts [...]
Modeling Stratospheric Polar Vortex Variation and Identifying Vortex Extremes Using Explainable Machine Learning
Published: 2022-10-01
Subjects: Physical Sciences and Mathematics
The winter stratospheric polar vortex (SPV) exhibits considerable variability in magnitude and structure, which can result in extreme SPV events. These extremes can subsequently influence weather in the troposphere from weeks to months and thus are important sources of surface predictability. However, the predictability of the SPV extreme events is limited to 1-2 weeks in state-of-the-art [...]
Global groundwater warming
Published: 2022-10-01
Subjects: Earth Sciences, Physical Sciences and Mathematics
Aquifers contain the largest store of unfrozen freshwater, making groundwater critical for life on Earth. Groundwater temperatures infl uence stream thermal regimes, groundwater-dependent ecosystems, aquatic biogeochemical processes, water quality, and the geothermal potential. Yet little is known about how groundwater responds to surface warming across spatial and temporal scales. We simulate [...]
Post-salt magmatism in the Campos Basin, offshore SE Brazil: style, distribution, and relationship to salt tectonics
Published: 2022-09-28
Subjects: Physical Sciences and Mathematics
Substantial magmatism occurred during the development of the marginal basins of the central and southern South Atlantic. Situated on the Brazilian side of the central segment, the Campos and Santos basin represent a transitional margin, located between the magma-rich margin in the north and the magma-poor margin in the south. In addition to magmatism associated with the initiation of continental [...]
Cautionary tales from the mesoscale eddy transport tensor
Published: 2022-09-26
Subjects: Physical Sciences and Mathematics
The anisotropic mesoscale eddy transport tensor is diagnosed using passive tracers advected in both an idealized 101-member mesoscale-resolving quasi-geostrophic (QG) double-gyre ensemble, and a realistic 24-member eddying ($1/12^\circ$) ensemble of the North Atlantic. We assert that the Reynold's decomposition along the ensemble dimension, rather than the spatial or temporal dimension, allows us [...]
All aboard! Earth system investigations with the CH2O-CHOO TRAIN v1.0
Published: 2022-09-24
Subjects: Climate, Earth Sciences, Geochemistry, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Models of the carbon cycle and climate on geologic (>10^4 year) timescales have improved tremendously in the last 50 years due to parallel advances in our understanding of the Earth system and the increase in computing power to simulate its key processes. Despite these advances, balancing the Earth System's vast complexity with a model's computational expense is a primary challenge in model [...]
CloudSEN12 - a global dataset for semantic understanding of cloud and cloud shadow in Sentinel-2
Published: 2022-09-24
Subjects: Computer Sciences, Earth Sciences, Physical Sciences and Mathematics
Accurately characterizing clouds and their shadows is a long-standing problem in the Earth Observation community. Recent works showcase the necessity to improve cloud detection methods for imagery acquired by the Sentinel-2 satellites. However, the lack of consensus and transparency in existing reference datasets hampers the benchmarking of current cloud detection methods. Exploiting the [...]
Intra-channel detachment in a collisional orogen: the Jhala Normal Fault in the Bhagirathi river section, Garhwal Higher Himalaya, India
Published: 2022-09-24
Subjects: Physical Sciences and Mathematics
In the Bhagirathi River Transect of the Garhwal Himalaya, India, the existence of the Jhala Normal Fault (JNF) and its movement sense are disputed. The JNF has been considered either as part of the South Tibetan Detachment System (STDS) or as a distinct, more southerly discontinuity within the Higher Himalayan Crystalline Sequence (HHCS). Field studies reveal that the JNF lies entirely within the [...]
Complex evolution of the 2016 Kaikoura earthquake revealed by teleseismic body waves
Published: 2022-09-23
Subjects: Physical Sciences and Mathematics
The 2016 Kaikoura earthquake, New Zealand, ruptured more than a dozen faults, making it difficult to prescribe a model fault for analysing the event by inversion. To model this earthquake from teleseismic records, we used a potency density tensor inversion, which projects multiple fault slips onto a single model fault plane, which reduced the non-uniqueness due to the uncertainty in selecting the [...]
Marine Radiocarbon Calibration in Polar Regions: A Simple Approximate Approach using Marine20
Published: 2022-09-22
Subjects: Earth Sciences, Environmental Sciences, Mathematics, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Statistics and Probability
The Marine20 radiocarbon (14C) age calibration curve, and all earlier marine radiocarbon calibration curves from the IntCal group, must be used extremely cautiously for the calibration of marine 14C samples from polar regions (outside ~ 40ºS – 40ºN) during glacial periods. Calibrating polar 14C marine samples from glacial periods against any Marine calibration curve (Marine20 or any earlier [...]
Ocean heat uptake efficiency increase since 1970
Published: 2022-09-21
Subjects: Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The ocean stores the bulk of anthropogenic heat in the Earth system. The ocean heat uptake efficiency (OHUE) -- the flux of heat into the ocean per degree of global warming -- is therefore a key factor in how much warming will occur in the coming decades. In climate models, OHUE is well-characterised, tending to decrease on centennial timescales; in contrast, OHUE is not well-constrained from [...]
Volcanic Lightning and Prebiotic Chemistry on the Early Earth
Published: 2022-09-16
Subjects: Chemistry, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Based on the paper by Pan et al., on the early Earth >4.2 Ga with limited exposed land areas, coupled with an ice covered ocean, lightning could have been rare. This presents a conundrum because lightning is considered to be an important energy source needed for the synthesis of prebiotic compounds required for the origin of life. Lightning occurrence during eruptions on wide spread volcanic [...]
Secular change of true polar wander over the past billion years
Published: 2022-09-15
Subjects: Physical Sciences and Mathematics
The rate of movement of Earth’s solid shell relative to its spin axis, or true polar wander, depends on variations in mantle convection and viscosity. We report paleomagnetic and geochronologic data from South China that constrain the rate of rapid true polar wander (>5° Myr-1) from 832–821 million years ago. Analysis of the paleomagnetic database demonstrates secular change of true polar wander [...]
The Equator Project
Published: 2022-09-10
Subjects: Education, Physical Sciences and Mathematics
Geography, Earth and Environmental Science (GEES) research will play a vital role in addressing the grand challenges of the 21st century, contributing to many of the UN sustainable development goals and the global energy transition. However, geoscience knowledge cannot be successfully applied to global problems that impact people from all walks of life unless the discipline itself is equitable. [...]