Preprints

Filtering by Subject: Volcanology

Heat does not physically flow in the ways assumed by greenhouse-warming theory

Peter L Ward

Published: 2020-06-06
Subjects: Climate, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Volcanology

Heat is currently defined as an amount of thermal energy flowing each second per unit area. Temperature is assumed to result from the net amount of heat flowing—the sum of all radiative forcings. Yet direct and unambiguous observations of Nature show that macroscopic temperature of solid matter results from a very broad spectrum of sub-microscopic oscillations of all the bonds holding matter [...]

Eruptive dynamics in Plinian silicic eruptions

Sahand Hajimirza, Helge M. Gonnermann, James E. Gardner

Published: 2020-06-04
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology

Plinian eruptions are characterized by high magma discharge rates and pyroclastic material containing extraordinary large numbers of bubbles. Upon ascent to the surface magma decompresses and volatiles become supersaturated, causing bubbles to nucleate with a rate dependent on the degree of supersaturation. Thus, the conventional view is that the number of bubbles nucleating within the erupting [...]

New understanding of hybrid pyroclastic processes revealed from proximal deposits: implications for uncertainty in volcanic hazard assessment

Natasha Joanne Dowey, Rebecca Williams

Published: 2020-05-25
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology

The deposits of Plinian and sub-Plinian eruptions provide critical insights into the behaviour and magnitude of past volcanic events, and inform numerical models that aim to mitigate against future volcanic hazards. However, pyroclastic deposits are often considered from either a fallout or flow perspective, with relatively little attention given to the complex spectrum of hybrid processes that [...]

Upper mantle mush zones beneath low melt flux ocean island volcanoes: insights from Isla Floreana, Galápagos

Matthew Gleeson, Sally A Gibson, Michael J. Stock

Published: 2020-05-25
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Volcanology

The physicochemical characteristics of sub-volcanic magma storage regions have important implications for magma system dynamics and pre-eruptive behaviour. The architecture of magma storage regions located directly above high buoyancy flux mantle plumes (such as Kīlauea, Hawai’i and Fernandina, Galápagos) are relatively well understood. However, far fewer constraints exist on the nature of magma [...]

Holocene tephrochronology of Kerguelen Archipelago, Subantarctic Indian Ocean

Fabien Arnaud, Pierre Sabatier, Anouk Leloup, Aymerick Servettaz, Bertrand Moine, Anne-Lise Develle, Stéphane Guédron, Vincent Perrot, Cécile Pignol, Jérôme Poulenard

Published: 2020-05-20
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Volcanology

Up to now, no geochemical or geochronological data has been published about Holocene volcanic activity on the Kerguelen Archipelago. Here we present the first continuous Holocene chronology of volcanic eruptions on the archipelago. We compared sedimentological, geochronological and geochemical data from two lake sediment cores taken in two different depocenters of Lake Armor, located ca. 70 km [...]

A radial hydraulic fracture with pressure-dependent leak-off

Evgenii Kanin, Egor Dontsov, Dmitry Garagash, Andrei A. Osiptsov

Published: 2020-05-06
Subjects: Earth Sciences, Environmental Sciences, Hydrology, Oil, Gas, and Energy, Physical Sciences and Mathematics, Volcanology

This paper investigates the problem of a radial (or penny-shaped) hydraulic fracture propagating in a permeable reservoir. In particular, we consider the fluid exchange between the crack and ambient porous media as a pressure-dependent process. In most of the existing models, the fluid exchange process is represented as one-dimensional pressure-independent leak-off described by Carters law. We [...]

Interferometric Processing of ScanSAR Data Using Stripmap Processor: New Insights from Coregistration

Cunren Liang, Eric Jameson Fielding

Published: 2020-04-14
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Computer Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Geology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology

Processing scanning synthetic aperture radar (ScanSAR) data using a stripmap processor, which is called full-aperture processing, has been the choice of many researchers. ScanSAR data are known to require very high azimuth coregistration precision which is usually achieved by a geometrical coregistration followed by a spectral diversity coregistration on the ScanSAR burst. However, for [...]

Interferometry with ALOS-2 full-aperture ScanSAR data

Cunren Liang, Eric Jameson Fielding

Published: 2020-04-14
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Geology, Geophysics and Seismology, Glaciology, Mining Engineering, Other Engineering, Physical Sciences and Mathematics, Physics, Tectonics and Structure, Volcanology

Advanced Land Observing Satellite-2 (ALOS-2) is designed to routinely acquire both scanning synthetic aperture radar (ScanSAR) and stripmap data. In this paper, we present a special multiband bandpass filter (MBF) to remove azimuth nonoverlap spectra for the interferometric processing of ALOS-2 full-aperture ScanSAR product. As required by the MBF, we estimate the important ScanSAR system [...]

InSAR Time Series Analysis of L-band Wide- Swath SAR Data Acquired by ALOS-2

Cunren Liang, Zhen Liu, Eric Jameson Fielding, Roland Bürgmann

Published: 2020-04-12
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Environmental Sciences, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology

Operating at L-band (~24 cm wavelength) in wide-swath modes is one of the characteristics of the new and next generation satellite synthetic aperture radar (SAR) missions. After 3 years of operation, the Japan Aerospace Exploration Agency Advanced Land Observing Satellite-2 (ALOS-2) satellite has acquired a wealth of L-band wide-swath SAR data over many areas using its ScanSAR mode. We present [...]

Measuring Azimuth Deformation With L-Band ALOS-2 ScanSAR Interferometry

Cunren Liang, Eric Jameson Fielding

Published: 2020-04-06
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Computational Engineering, Computer Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Signal Processing, Tectonics and Structure, Volcanology

We analyze the methods for measuring azimuth deformation with the L-band Advanced Land Observing Satellite-2 (ALOS-2) scanning synthetic aperture radar (ScanSAR) interferometry. To implement the methods, we extract focused bursts from the ALOS-2 full-aperture product, which is the only product available for ScanSAR interferometry at present. The extracted bursts are properly processed to measure [...]

Estimating Azimuth Offset With Double-Difference Interferometric Phase: The Effect of Azimuth FM Rate Error in Focusing

Cunren Liang, Eric Jameson Fielding, Mong-Han Huang

Published: 2020-04-06
Subjects: Aerospace Engineering, Civil and Environmental Engineering, Earth Sciences, Electrical and Computer Engineering, Engineering, Environmental Sciences, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mining Engineering, Other Earth Sciences, Physical Sciences and Mathematics, Physics, Tectonics and Structure, Volcanology

Estimating azimuth offset with double-difference interferometric (DDI) phase, which is called multiple-aperture interferometric synthetic aperture radar (InSAR) or spectral diversity, is increasingly used in recent years to measure azimuth deformation or to accurately coregister a pair of InSAR images. We analyze the effect of frequency modulation (FM) rate error in focusing on the DDI phase with [...]

Ultraviolet camera measurements of passive and explosive sulphur dioxide emissions at Yasur volcano, Vanuatu

Tehnuka Ilanko, Tom Pering, Thomas Charles Wilkes, Julia Woitischek, Roberto D'Aleo, Alessandro Aiuppa, Andrew J.S. McGonigle, Marie Edmonds, Esline Garaebiti

Published: 2020-03-31
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology

Here, we present the first ultraviolet (UV) camera measurements of sulphur dioxide (SO2) flux from Yasur volcano, Vanuatu, for the period 6th – 9th July 2018. These data yield the first direct gas measurement-derived calculations of explosion gas masses at Yasur. Yasur typically exhibits persistent passive gas release interspersed with frequent strombolian explosions. We used compact forms of the [...]

International disparities in open access practices of the Earth Sciences community

Olivier Pourret, David William Hedding, Dasapta Erwin Irawan, Haiyan Liu, Jonathan Tennant

Published: 2020-03-31
Subjects: Biogeochemistry, Cosmochemistry, Earth Sciences, Geochemistry, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Library and Information Science, Mineral Physics, Other Earth Sciences, Paleobiology, Paleontology, Physical Sciences and Mathematics, Sedimentology, Social and Behavioral Sciences, Soil Science, Speleology, Stratigraphy, Tectonics and Structure, Volcanology

Short communication on international disparities in open access practices of the Earth Sciences community

Structural controls on the location, geometry, and longevity of an intraplate volcanic system - The Tuatara Volcanic Field, Great South Basin, New Zealand

Thomas Phillips, Craig Magee

Published: 2020-03-18
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology

Intraplate volcanism is widely distributed across continental interiors. Yet controls on the location, 3D geometry, and longevity of many individual intraplate volcanic systems are often poorly understood. Geophysical and geodetic data provide insights into active intraplate magma plumbing systems, particularly when coupled with petrological and chemical analyses of volcanic products, but these [...]

Magma diversity reflects recharge regime and thermal structure of the crust

Gregor Weber, Guy Simpson, Luca Caricchi

Published: 2020-03-03
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Volcanology

The chemistry of magmas erupted by volcanoes is a message from deep within the Earth’s crust, which if decrypted, can provide essential information on magmatic processes occurring at inaccessible depths. While some volcanoes are prone to erupt magmas of a wide compositional variety, others sample rather monotonous chemistries through time. Whether such differences are a consequence of physical [...]

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