Preprints
Filtering by Subject: Physical Sciences and Mathematics
Investigating potential icequakes at Llaima volcano, Chile
Published: 2019-10-24
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics, Volcanology
Glacially- and magmatically-derived seismic events have been noted to heavily overlap in characteristics, thus there exists the potential for false-alarms or missed warnings at ice-covered volcanoes. Here we present the first study to specifically target icequakes at an ice-covered volcano in Southern Chile. Two months of broadband seismic data collected at Llaima volcano in 2015 were analyzed in [...]
Pre-breakup extension in the northern North Sea defined by complex strain partitioning and heterogeneous extension rates
Published: 2019-10-24
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The early stages of continental rifting are accommodated by the growth of upper-crustal normal fault systems that are distributed relatively evenly across the rift width. Numerous fault systems define fault arrays, the kinematics of which are poorly understood due to a lack of regional studies drawing on high-quality subsurface data. Here we investigate the long-term (~150 Myr) growth of a [...]
Rotation, narrowing, and preferential reactivation of brittle structures during oblique rifting
Published: 2019-10-24
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Occurrence of multiple faults populations with contrasting orientations in oblique continental rifts and passive margins has long sparked debate about relative timing of deformation events and tectonic interpretations. Here, we use high-resolution three-dimensional thermo-mechanical numerical modeling to characterize the evolution of the structural style associated with varying geometries of [...]
Linking the evolution of terrestrial interiors and an early outgassed atmosphere to astrophysical observations
Published: 2019-10-17
Subjects: Astrophysics and Astronomy, Earth Sciences, Geophysics and Seismology, Other Astrophysics and Astronomy, Physical Sciences and Mathematics, Planetary Geophysics and Seismology, Planetary Sciences
A terrestrial planet is molten during formation and may remain molten due to intense insolation or tidal forces. Observations favour the detection and characterisation of hot planets, potentially with large outgassed atmospheres. We aim to determine the radius of hot Earth-like planets with large outgassing atmospheres. Our goal is to explore the differences between molten and solid silicate [...]
Rock strength and structural controls on fluvial erodibility: implications for drainage divide mobility in a collisional mountain belt
Published: 2019-10-14
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
Numerical model simulations and experiments have suggested that when migration of the main drainage divide occurs in a mountain belt, it can lead to the rearrangement of river catchments, rejuvenation of topography, and changes in erosion rates and sediment flux. We assess the progressive mobility of the drainage divide in three lithologically and structurally distinct groups of bedrock in the [...]
Plate tectonics drive deep biosphere microbial community structure
Published: 2019-10-14
Subjects: Earth Sciences, Environmental Microbiology and Microbial Ecology Life Sciences, Life Sciences, Microbiology, Other Earth Sciences, Physical Sciences and Mathematics
The deep subsurface is one of Earth’s largest biomes. Here, microorganisms modify volatiles moving between the deep and surface Earth. However, it is unknown whether large-scale tectonic processes affect the distribution of microorganisms across this subterranean landscape. We sampled subsurface microbial ecosystems in deeply-sourced springs across the Costa Rican convergent margin. Noble gases, [...]
“Conjugate margins” – An oversimplification of the complex southern North Atlantic rift and spreading system?
Published: 2019-10-14
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
The prevalence of conjugate margin terminology and studies in the scientific literature is testimony to the contribution that this concept and approach has made to the study of passive margins, and more broadly extensional tectonics. However, when applied to the complex rift, transform and spreading system of the southern North Atlantic (i.e. the passive margins of Newfoundland, Labrador, [...]
River inflow dominates methane emissions in an Arctic coastal system
Published: 2019-10-13
Subjects: Biogeochemistry, Earth Sciences, Environmental Monitoring, Environmental Sciences, Fresh Water Studies, Geochemistry, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Measurements of greenhouse gases in Arctic waters are strongly biased toward low-ice summer conditions, with few observations during periods of seasonal ice retreat. We present a year-round time series of dissolved methane (CH4) and nitrous oxide (N2O), along with targeted observations during ice melt of CH4 and carbon dioxide (CO2) in a river and estuary adjacent to Cambridge Bay, Nunavut, [...]
The 2018 Fiji Mw 8.2 and 7.9 deep earthquakes: one doublet in two slabs
Published: 2019-10-13
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The cold Fiji-Tonga subduction zone accounts for >75% of cataloged deep earthquakes but none of the largest ten in the last century. On 19 August 2018 and 06 September 2018, a deep earthquake doublet with moment magnitude (Mw) 8.2 and 7.9 struck the Fiji area, providing a rare opportunity to interrogate the behaviors of great deep earthquakes in cold slabs. By cursory examination, the doublet [...]
Redshift of Earthquakes via Focused Blind Deconvolution of Teleseisms
Published: 2019-10-13
Subjects: Applied Mathematics, Earth Sciences, Electrical and Computer Engineering, Engineering, Geophysics and Seismology, Physical Sciences and Mathematics, Signal Processing
We present a robust factorization of the teleseismic waveforms resulting from an earthquake source into signals that originate from the source and signals that characterize the path effects. The extracted source signals represent the earthquake spectrum and its variation with azimuth. Unlike most prior work on source extraction, our method is data-driven, and it does not depend on any [...]
Making mountains on Earth and beyond
Published: 2019-10-13
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
Many of Earth’s mountains are formed in orogenic belts aligned along plate margins. Their altitudes (reaching >8,000 m above sea level in the Himalayas) are the result of the balance between tectonic forces causing their uplift and erosive processes causing their destruction. The tectonic forces result, in part, from isostacy which is determined by the plasticity of the asthenosphere, but [...]
Magnetotelluric multiscale 3-D inversion reveals crustal and upper mantle structure beneath the Hangai and Gobi-Altai region in Mongolia
Published: 2019-10-12
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Central Mongolia is a prominent region of intracontinental surface deformation and intraplate volcanism. To study these processes, which are poorly understood, we collected magnetotelluric data in the Hangai and Gobi-Altai region in central Mongolia and derived the first three-dimensional (3-D) resistivity model of the crustal and upper mantle structure in this region. The geological and tectonic [...]
Noise-derived broadband full Green functions for a radially layered Earth
Published: 2019-10-11
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The emerging noise correlation technique provides a way to approximate the Green function of medium with the correlation function between ambient noise wavefields. It has been recognized that not only the regularly observable seismic phase, but also spurious phases that have no correspondence in real seismograms, are constructed from noise correlations. In this study, we synthesize global noise [...]
The sensitivity of estimates of multiphase fluid and solid properties of porous rocks to image processing
Published: 2019-10-11
Subjects: Chemical Engineering, Civil and Environmental Engineering, Earth Sciences, Engineering, Hydrology, Petroleum Engineering, Physical Sciences and Mathematics, Transport Phenomena
X-ray microcomputed tomography X-ray microCT) is a rapidly advancing technology that has been successfully employed to study flow phenomena in porous media. It offers an alternative approach to core scale experiments for the estimation of traditional petrophysical properties such as porosity and single-phase flow permeability. It can also be used to investigate properties that control multiphase [...]
Skillful multiyear predictions of ocean acidification in the California Current System
Published: 2019-10-11
Subjects: Biogeochemistry, Climate, Earth Sciences, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The California Current System (CCS) sustains economically valuable fisheries and is particularly vulnerable to ocean acidification, due to the natural upwelling of corrosive waters that affect ecosystem function. Marine resource managers in the CCS could benefit from advanced knowledge of ocean acidity on multiyear timescales. We use a novel suite of retrospective forecasts with an initialized [...]