Preprints
Filtering by Subject: Physical Sciences and Mathematics
History of on-board equipment improvement for GNSS-A observation with focus on observation frequency
Published: 2020-02-12
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The Global Navigation Satellite System-Acoustic ranging combination technique (GNSS-A) is a seafloor geodetic technique that enables precise global seafloor positioning to detect subseafloor geophysical phenomena. The technique requires a sea surface observation platform that combines GNSS positioning and acoustic ranging. Currently, a survey vessel is used as the platform, which entails [...]
The 2019 MW 5.7 Changning earthquake, Sichuan Basin, China – a shallow doublet with different faulting styles
Published: 2020-02-12
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The increased seismic activity of the last ~10 years in Changning county of Sichuan Province comprised just small (mostly ML < 5.0) injection-induced earthquakes. The MW 5.7 earthquake of June 17, 2019 is the largest event ever reported there. Moment tensor of the mainshock was remarkably dominated by a compensated linear vector dipole. We resolve its fine structure showing it was a doublet, [...]
Did sea-level change cause the switch from fissure-type to central-type volcanism at Mount Etna, Sicily?
Published: 2020-02-11
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
One of the most intriguing aspects of the evolution of Mount Etna (eastern Sicily) is the switch from a fissure-type shield volcano coincident with the Ionian coast to an inland cluster of nested stratovolcanoes close to the currently active centre. Previous geological studies infer that the switch reflects a tectonically-driven rearrangement of the major border faults that direct the Etnean [...]
Impact of topography on earthquake static slip inversions
Published: 2020-02-11
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Our understanding of earthquakes is limited by our knowledge, and our description, of the physics of the Earth. When solving for subsurface fault slip, it is common practice to assume minimum complexity for the Earths characteristics such as topography, fault geometry and elastic properties. These characteristics are difficult to include in simulations and our knowledge of them is incomplete, [...]
Stress Changes on the Garlock fault during and after the 2019 Ridgecrest Earthquake Sequence
Published: 2020-02-08
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The recent 2019 Ridgecrest earthquake sequence in Southern California jostled the seismological community by revealing a complex and cascading foreshock series that culminated in a M7.1 mainshock. But the central Garlock fault, despite being located immediately south of this sequence, did not coseismically fail. Instead, the Garlock fault underwent post-seismic creep and exhibited a sizeable [...]
Chalcophile elements track the fate of sulfur at Kīlauea Volcano, Hawai’i
Published: 2020-02-08
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Volcanology
Chalcophile element concentrations in melt inclusions and matrix glasses may be used to investigate low pressure degassing processes, as well as sulfide saturation during crustal fractionation, and mantle melting. Erupted products from Kīlauea Volcano, Hawaiʻi, record three stages of sulfide saturation (in the mantle, crust, and within lava lakes), separated by episodes of sulfide resorption [...]
Iron mineral dissolution releases iron and associated organic carbon during permafrost thaw
Published: 2020-02-07
Subjects: Environmental Microbiology and Microbial Ecology Life Sciences, Environmental Sciences, Life Sciences, Microbiology, Physical Sciences and Mathematics
It has been shown that reactive soil minerals, specifically iron(III) (oxyhydr)oxides, can trap organic carbon in soils overlying intact permafrost, and may limit carbon mobilization and degradation as it is observed in other environments. However, the use of iron(III)-bearing minerals as terminal electron acceptors in permafrost environments and thus their stability and capacity to prevent [...]
Urgent Tsunami Computing
Published: 2020-02-07
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Tsunamis pose a hazard that may strike a coastal population within a short amount of time. To effectively forecast and warn for tsunamis, extremely fast simulations are needed. However, until recently such urgent tsunami simulations have been infeasible in the context of early warning and even for high-resolution rapid post-event assessment. The implementation of efficient tsunami numerical codes [...]
Drivers of Local Ocean Heat Content Variability in ECCOv4
Published: 2020-02-06
Subjects: Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Variation in upper ocean heat content is a critical factor in understanding global climate variability. By using temperature anomaly budgets in a physically consistent ocean state estimate we describe the balance between atmospheric forcing and ocean transport mechanisms for different depth horizons and at varying temporal and spatial resolutions. The processes controlling local variations in [...]
The what, how and why of human coprolite analysis in archaeology
Published: 2020-02-06
Subjects: Earth Sciences, Environmental Sciences, Environmental Studies, Life Sciences, Other Earth Sciences, Physical Sciences and Mathematics, Social and Behavioral Sciences
Coprolites are a highly informative but still underutilized proxy for understanding past environments, palaeodiets, and ancient human health. Here we provide a critical review of the history and current state of research in human coprolite analysis encompassing, macroscopic, microscopic, and biomolecular approaches. We present new data from a number of key sites which demonstrates how new [...]
Comparison of permeability predictions on cemented sandstones with physics-based and machine learning approaches
Published: 2020-02-06
Subjects: Chemical Engineering, Earth Sciences, Engineering, Hydrology, Multivariate Analysis, Petroleum Engineering, Physical Sciences and Mathematics, Statistics and Probability
Permeability prediction has been an important problem since the time of Darcy. Most approaches to solve this problem have used either idealized physical models or empirical relations. In recent years, machine learning (ML) has led to more accurate and robust, but less interpretable empirical models. Using 211 core samples collected from 12 wells in the Garn Sandstone from the North Sea, this [...]
‘Scallywag Bunkers’: Geophysical Investigations of WW2 Auxiliary Unit Operational Bases (OBs) in the UK
Published: 2020-02-05
Subjects: Earth Sciences, Education, Geography, Other Earth Sciences, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics, Social and Behavioral Sciences
In 1940, with the fall of France imminent, Britain prepared for invasion. After Dunkirk, with most armour and transport lost, a defence ‘stop line’ (GHQ Line) was prepared. Local Defence Volunteers (later Home Guard) were raised to buy time for the Home Army to deploy. Secret ‘Auxiliary Units’ were also formed, tasked with ‘Scallywagging’ – guerrilla activities ––in the invading army’s rear. 4-8 [...]
Centrifugal and symmetric instability during Ekman adjustment of the bottom boundary layer
Published: 2020-02-04
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Flow along isobaths of a sloping lower boundary generates an across-isobath Ekman transport in the bottom boundary layer. When this Ekman transport is down the slope it causes convective mixing --- much like a downfront wind in the surface boundary layer --- destroying stratification and potential vorticity. In this manuscript we show how this can lead to the development of a forced centrifugal [...]
A new model for fault growth during syn-kinematic deposition
Published: 2020-02-04
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Constraining the mechanisms of fault growth is essential for understanding extensional tectonics. In these dynamic systems the propagation of existing faults through recent syn-kinematic depositions is a poorly understood yet critical process. To understand how underlying structures influence faulting, we examine fault growth in a 10 kyr magmatically-resurfaced region of the Krafla fissure swarm, [...]
Fault rupture during the December 26, 2018, Mw 4.9 Fleri earthquake (Mt. Etna): surface faulting in a volcano-tectonic environment
Published: 2020-02-04
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
On December 26, 2018, the largest instrumental earthquake ever recorded in Mt. Etna (Sicily, southern Italy) shook the eastern flank of the volcano, with epicenter near the Fleri village along the right-lateral Fiandaca Fault (focal depth less than 1 km, Mw 4.9). The mainshock was accompanied by widespread surface faulting. We surveyed and mapped the coseismic ground ruptures and collected [...]