Preprints
Filtering by Subject: Earth Sciences
Iron oxide reactivity controls organic matter mineralization in ferruginous sediments
Published: 2020-07-10
Subjects: Biogeochemistry, Earth Sciences, Life Sciences, Physical Sciences and Mathematics
Ferruginous sediments were widespread during the Archaean and Proterozoic Eons, but our knowledge about organic matter mineralization remains mostly conceptual, as analogous modern ferruginous sediments are largely unstudied. In sediments of ferruginous Lake Towuti, Indonesia, methanogenesis dominates organic matter mineralization despite abundant reactive ferric iron phases persisting throughout [...]
Habitability of the early Earth: Liquid water under a faint young Sun facilitated by strong tidal heating due to a nearby Moon
Published: 2020-07-10
Subjects: Astrophysics and Astronomy, Earth Sciences, Other Astrophysics and Astronomy, Other Earth Sciences, Physical Sciences and Mathematics, Planetary Sciences, The Sun and the Solar System
Geological evidence suggests liquid water near the Earths surface as early as 4.4 gigayears ago when the faint young Sun only radiated about 70 % of its modern power output. At this point, the Earth should have been a global snowball. An extreme atmospheric greenhouse effect, an initially more massive Sun, release of heat acquired during the accretion process of protoplanetary material, and [...]
Fracture mechanics of rate-and-state faults and fluid injection induced slip
Published: 2020-07-08
Subjects: Earth Sciences, Engineering, Environmental Sciences, Geophysics and Seismology, Oil, Gas, and Energy, Physical Sciences and Mathematics, Physics
Propagation of a slip transient on a fault with rate-and-state dependent friction resembles a fracture which near tip region is characterized by large departure of the slip velocity and fault strength from the steady-state sliding. We develop a near tip solution to describe this unsteady dynamics, and obtain the fracture energy Gc, dissipated in overcoming strength-excursion away from [...]
An Early Pliocene relative sea level record from Patagonia (Argentina)
Published: 2020-07-08
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
We report a geological unit surveyed and dated in central Patagonia, Argentina (Camarones town, San Jorge Gulf). The unit was interpreted as representative of an intertidal environment and dated to the Early Pliocene (4.69-5.23 Ma) with strontium isotope stratigraphy. The elevation of this unit was measured with differential GPS at ca. 36 m above present-day sea level. Considering modern tidal [...]
Application of the tilt derivative transform to bathymetric data for structural lineament mapping
Published: 2020-07-08
Subjects: Computer Sciences, Earth Sciences, Geomorphology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Tectonics and Structure
High-resolution bathymetry surveys provide an opportunity to analyse local geological structure where onshore areas afford limited exposure. Semi-automated lineament detection methods are necessary for areas of large coverage where a manual analysis would be subjective and time-consuming. However, semi-automated approaches are dependent on effective feature extraction methods to identify genuine [...]
GANSim: Conditional Facies Simulation Using an Improved Progressive Growing of Generative Adversarial Networks (GANs)
Published: 2020-07-05
Subjects: Artificial Intelligence and Robotics, Computer Sciences, Earth Sciences, Geology, Hydrology, Mathematics, Physical Sciences and Mathematics, Sedimentology, Statistical Models, Statistics and Probability
Conditional facies modeling combines geological spatial patterns with different types of observed data, to build earth models for predictions of subsurface resources. Recently, researchers have used generative adversarial networks (GANs) for conditional facies modeling, where an unconditional GAN is first trained to learn the geological patterns using the original GANs loss function, then [...]
Deep spatial transformers for autoregressive data-driven forecasting of geophysical turbulence
Published: 2020-07-05
Subjects: Artificial Intelligence and Robotics, Atmospheric Sciences, Climate, Computer Sciences, Dynamical Systems, Earth Sciences, Environmental Sciences, Fluid Dynamics, Geophysics and Seismology, Mathematics, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics
A deep spatial transformer based encoder-decoder model has been developed to autoregressively predict the time evolution of the upper layers stream function of a two-layered quasi-geostrophic (QG) system without any information about the lower layers stream function. The spatio-temporal complexity of QG flow is comparable to the complexity of 500hPa Geopotential Height (Z500) of fully coupled [...]
Exposure and vulnerability estimation for modelling flood losses to commercial assets in Europe
Published: 2020-07-05
Subjects: Earth Sciences, Hydrology, Multivariate Analysis, Physical Sciences and Mathematics, Statistics and Probability
Commercial assets comprise buildings, machinery and equipment, which are susceptible to floods. Existing damage models and exposure estimation methods for this sector have limited transferability between flood events. In this study we introduce two methodologies aiming at broader applicability: (1) disaggregation of economic statistics to obtain detailed building-level estimates of replacement [...]
Post-processing the National Water Model with Long Short- Term Memory Networks for Streamflow Predictions and Model Diagnostics
Published: 2020-07-01
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
We build three Long Short-Term Memory (LSTM) daily streamflow prediction models (deep learning networks) for 531 basins across the contiguous United States (CONUS), and compare their performance: (1) a LSTM post-processor trained on the U.S. National Water Model (NWM) outputs (LSTM_PP) as a target variable, (2) a LSTM post-processor trained on the NWM outputs and using atmospheric forcings [...]
Seismic swarm preceding the 2017 Mount Agung eruption in Bali (Indonesia) enhanced by the matched filter approach
Published: 2020-07-01
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Intense swarm seismicity took place before the 2017 Mount Agung eruption in Bali (Indonesia). However, the earthquake sequences were not well documented. In addition, there was a substantial delay between the peak of the seismic activity (late September) and the onset of the impending eruption (late November). We applied waveform-based hypocenter relocation and matched filter technique (MFT) to [...]
“Empirical pre-whitening” spectral analysis detects periodic but inconsistent signals in abyssal hill morphology at the southern East Pacific Rise
Published: 2020-07-01
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
The existence, or not, of periodicities in abyssal hill morphology has been vigorously debated in recent publications, and some have hypothesized that such periodicities are evidence of the impact of Milankovitch cycle-caused sea level fluctuations on the volcanic construction process at mid-ocean ridges. Periodicities are detected by the presence of spectral peaks that rise significantly above [...]
Machine learning and fault rupture: a review
Published: 2020-07-01
Subjects: Artificial Intelligence and Robotics, Computer Sciences, Earth Sciences, Geophysics and Seismology, Mathematics, Physical Sciences and Mathematics, Theory and Algorithms
Geophysics has historically been a data-driven field, however in recent years the exponential increase of available data has lead to increased adoption of machine learning techniques and algorithm for analysis, detection and forecasting applications to faulting. This work reviews recent advances in the application of machine learning in the study of fault rupture ranging from the laboratory to [...]
Influences on Discharge Partitioning on a Large River Delta: Case Study of the Mississippi-Atchafalaya Diversion, 1926–1950
Published: 2020-07-01
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
The modern Mississippi River (M.R.) Delta is plumbed by the Mississippi and Atchafalaya rivers, setting water and sediment dispersal pathways for Earth’s fifth-largest river system. The Atchafalaya River’s (A.R.) partial annexation of discharge from the M.R., particularly between 1926 and 1950, prompted warnings of a rapid river avulsion and the construction of the Old River Control Structure to [...]
Tidal Modulation of Antarctic Ice Shelf Melting
Published: 2020-07-01
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Tides influence basal melting of individual Antarctic ice shelves, but their net impact on Antarctic-wide ice-ocean interaction has yet to be constrained. Here we quantify the impact of tides on ice shelf melting and the continental shelf seas by means of a 4 km resolution circum-Antarctic ocean model. Activating tides in the model increases the total basal mass loss by 57 Gt/yr (4 %), while [...]
Dislocation interactions in olivine control postseismic creep of the upper mantle
Published: 2020-06-29
Subjects: Condensed Matter Physics, Earth Sciences, Geology, Mineral Physics, Physical Sciences and Mathematics, Physics, Tectonics and Structure
Changes in stress applied to mantle rocks, such as those imposed by earthquakes, induce a period of evolution in viscosity and microstructure. This transient creep is often modelled based on stress transfer among slip systems due to grain interactions. However, recent experiments have demonstrated that the intragranular accumulation of stresses among dislocations is the dominant cause of strain [...]