1,709 research outputs found
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Coupled subdaily and multiweek cycles during the lava dome erupt of Soufriere Hills Volcano, Montserrat
No full textObservations of volcanoes extruding andesitic lava to produce lava domes often reveal cyclic behaviour. At Soufriere Hills Volcano, Montserrat, cycles with sub-daily and multi-week periods have been recognised on many occasions. These two types of cycle have been modelled separately as stick-slip magma flow at the junction between a dyke and an overlying cylindrical conduit (Costa et al. 2012), and as the filling and discharge of magma through the elastic-walled dyke (Costa et al., 2007a) respectively. Here, we couple these two models to simulate the behaviour over a period of well-observed multi-week cycles, with accompanying sub-daily cycles, from 13 May to 21 September 1997. The coupled model captures well the asymmetrical first-order behaviour: the first 40% of the multi-week cycle consists of high rates of lava extrusion during short period/high amplitude sub-daily cycles as the dyke reservoir discharges itself. The remainder of the cycle involves increasing pressurization as more magma is stored, and extrusion rate falls, followed by a gradual increase in the period of the sub-daily cycles
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Time series analysis of lava flux
No full textWe have applied time series analytical techniques to the flux of lava from an extrusive eruption. Tilt data acting as a proxy for flux are used in a case study of the May–August 1997 period of the eruption at Soufrière Hills Volcano, Montserrat. We justify the use of such a proxy by simple calibratory arguments. Three techniques of time series analysis are employed: spectral, spectrogram and wavelet methods. In addition to the well-known ~9-hour periodicity shown by these data, a previously unknown periodic flux variability is revealed by the wavelet analysis as a 3-day cycle of frequency modulation during June–July 1997, though the physical mechanism responsible is not clear. Such time series analysis has potential for other lava flux proxies at other types of volcanoes
Photograph of a bust of the author Tasma
No full textPhotograph of a bust of the author Tasma (Jessie Catherine Couvreur). Pencilled on verso of photo 'Tasma - enlargement of an original lent to H.M. Green? by Mrs Erdos, a neice of Tasma
A note on geographical systems and maps of Montserrat
No full textIt is often critically important that geospatial data are measured and mapped accurately, particularly for quantitative analyses and numerical modelling applications. Defining a geographical coordinate system requires a non-unique combination of geodetic techniques (e.g. ellipsoids, projections and geoids). The choice of geographical system presents scope for ambiguity and confusion about geographical data, especially those archived without appropriate metadata. Experience has shown that these confusions have been a repeating source of either frustration or inadvertent error for those using geographical data from Montserrat. This is, in part, probably due to common usage of multiple datums and the existence of numerous topographical datasets recorded during the past 150 years. Here, we attempt to provide a brief introduction to geodetic principles and their application to Montserrat geographical data. The differences between common datums are illustrated and we describe variations in magnetic declination as they apply to field use of magnetic instruments. We include a record of the source of the large-scale mapping datasets that have been used and analysed ubiquitously in the literature. The descriptions here are intended as an introductory reference resource for those using geographical data from Montserrat
Isogeometric analysis for multi-patch structured Kirchhoff–Love shells
No full textWe present an isogeometric method for Kirchhoff–Love shell analysis of shell structures with geometries composed of multiple patches and which possibly possess extraordinary vertices, i.e. vertices with a valency different to four. The proposed isogeometric shell discretisation is based on the one hand on the approximation of the mid-surface by a particular class of multi-patch surfaces, called analysis-suitable G1 (Collin et al., 2016), and on the other hand on the use of the globally C1-smooth isogeometric multi-patch spline space (Farahat et al., 2023). We use our developed technique within an isogeometric Kirchhoff–Love shell formulation (Kiendl et al., 2009) to study linear and non-linear shell problems on multi-patch structures. Thereby, the numerical results show the great potential of our method for efficient shell analysis of geometrically complex multi-patch structures which cannot be modelled without the use of extraordinary vertices.Funding Information: The authors wish to thank the anonymous reviewers for their comments that helped to improve the paper. A. Farahat and M. Kapl have been supported by the Austrian Science Fund (FWF) through the project P 33023-N. H.M. Verhelst is grateful for the funding from Delft University of Technology. J. Kiendl has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No 864482). Additionally, the authors are grateful for the support from the developers of the Geometry + Simulation Modules, in particular from A. Mantzaflaris (Inria Sophia Antipolis-Méditerranée). Funding Information: The authors wish to thank the anonymous reviewers for their comments that helped to improve the paper. A. Farahat and M. Kapl have been supported by the Austrian Science Fund (FWF) through the project P 33023-N . H.M. Verhelst is grateful for the funding from Delft University of Technology . J. Kiendl has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No 864482 ). Additionally, the authors are grateful for the support from the developers of the Geometry + Simulation Modules, in particular from A. Mantzaflaris (Inria Sophia Antipolis-Méditerranée).Numerical AnalysisShip Hydromechanics and Structure
Samuel H.M. Byers; Poet; Author; Diplomat; Oskaloosa; Iowa; Mahaska County; Iowa
No full textThis is a photograph taken of Samuel H.M. Byers at the onset of the Civil War in 1861. Byers served in the Union Army during the Civil War and gained a great deal of inspiration for his poetic writing during the war. Byers's most famous work is a poem entitled "Sherman's March to the Sea" recapping events that took place during this famous piece of American history. Byers is also credited with writing the state song of Iowa, played to the melody of "O, Christmas Tree". After gaining fame and fortune from his writing, Byers pursued a career in diplomacy, serving in the U.S. Consulate in Switzerland and Italy. Byers then came back to the U.S., living out the remainder of his days in Los Angeles, California. Byers died in 1933, at the age 95
L'Image Du Buddha Dans L'Art Lao
No full textText and photos of Buddha images in LaosL'Image Du Buddha Dans L'Art Lao. Vientiane: H.M. Demain, 197
Thermally-enhanced oil recovery from stranded fields: Synergy potential for geothermal and oil exploitation
No full textAccepted author manuscriptReservoir EngineeringApplied Geolog
Cure of codfish and herrings; Extracts for a work on the cure of codfish and herring
No full textUseful Hints on the Cure of Codfish and HerringsAt head of title: Official; "(Extracts from), reprinted, by permission, by H.M. inspectors for Irish Fisheries", "... having obtained the permission from Newfoundland Fisheries Commission ..." --page
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