scholarly journals Dynamic Magma Storage at Near‐Ridge Hot Spots: Evidence From New Galápagos Gravity Data

2020 ◽  
Vol 21 (3) ◽  
Author(s):  
Z. Cleary ◽  
D. M. Schwartz ◽  
E. Mittelstaedt ◽  
K. Harpp
Keyword(s):  
Hot Spots ◽  
Gravity Data ◽  
Magma Storage

Imaging magma storage in the Main Ethiopian Rift with 3-D Magnetotellurics

2020 ◽  
Author(s):  
Juliane Huebert ◽  
Kathy Whaler ◽  
Shimeles Fisseha ◽  
Fiona Iddon ◽  
Colin Hogg
Keyword(s):  
Water Content ◽  
Gravity Data ◽  
Receiver Functions ◽  
Magma Ascent ◽  
Ethiopian Rift ◽  
Volcanic Complex ◽  
Magma Storage ◽  
Energy Potential ◽  
Melt Mixing ◽  
Main Ethiopian Rift

<p>The Main Ethiopian Rift (MER) as part of the large East African continental break-up zone is characterized by lateral extension and active volcanism. Rifting in the MER is magma assisted, with surface expressions of magmatism concentrated at en echelon Quaternary magmatic segments and off-axis linear features, but questions still remain about their respective roles in rifting.</p><p>The storage and pathways of magma ascent are of great interest for the assessment of both geohazard and geothermal energy potential. Imaging magma storage throughout the crust and in the upper mantle can be achieved by geophysical deep sounding techniques such as magnetotellurics (MT). Through MT measurements it is possible to access the electrical conductivity of the subsurface, a parameter that is greatly sensitive to the melt and water content. We present new MT data from the Central MER and a three-dimensional model of conductivity of the crust, imaging across-rift magma storage not only under the well-developed central-axis silicic volcanic complex Aluto, but also under several off-axis basaltic monogenetic volcanic fields. The conductivity model supports the idea of bi-modal magma storage in the CMER and helps constrain the melt and water content in the crust through the use of petrological melt-mixing models. Integrating our findings with the results from seismic tomography and receiver functions as well as Bouguer gravity data and petrological observations allows a comprehensive picture of magma storage and pathways in the MER.</p>

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

World Bank pinpoints disaster hot spots

Nature ◽  
2005 ◽  
Author(s):  
Deirdre Lockwood
Keyword(s):  
World Bank ◽  
Hot Spots

Spatial Hotspot Analysis of Bucharest’s Urban Heat Island (UHI) Using Modis Data

2018 ◽  
Vol 18 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Georgiana Grigoraș ◽  
Bogdan Urițescu
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Land Surface Temperature ◽  
Hot Spots ◽  
Land Surface ◽  
Hot Spot ◽  
Monitoring Network ◽  
Residential Areas ◽  
Hotspot Analysis ◽  
The City

Abstract The aim of the study is to find the relationship between the land surface temperature and air temperature and to determine the hot spots in the urban area of Bucharest, the capital of Romania. The analysis was based on images from both moderate-resolution imaging spectroradiometer (MODIS), located on both Terra and Aqua platforms, as well as on data recorded by the four automatic weather stations existing in the endowment of The National Air Quality Monitoring Network, from the summer of 2017. Correlation coefficients between land surface temperature and air temperature were higher at night (0.8-0.87) and slightly lower during the day (0.71-0.77). After the validation of satellite data with in-situ temperature measurements, the hot spots in the metropolitan area of Bucharest were identified using Getis-Ord spatial statistics analysis. It has been achieved that the “very hot” areas are grouped in the center of the city and along the main traffic streets and dense residential areas. During the day the "very hot spots” represent 33.2% of the city's surface, and during the night 31.6%. The area where the mentioned spots persist, falls into the "very hot spot" category both day and night, it represents 27.1% of the city’s surface and it is mainly represented by the city center.

The family Orthotrichaceae (Bryophyta) in flora of Russia: results of revision and biogeographical review

2018 ◽  
Vol 52 (2) ◽  
pp. 519-534 ◽  
Author(s):  
V. E. Fedosov
Keyword(s):  
Hot Spots ◽  
Latitudinal Gradient ◽  
Hot Spot ◽  
Spatial Differentiation ◽  
Taxonomic Composition ◽  
Undescribed Species ◽  
Longitudinal Gradient ◽  
Biogeographic Pattern ◽  
The Family ◽  
North Pacific Region

Recent studies on Orthotrichoid mosses in Russia are summarized genus by genus. Orthotrichum furcatum Otnyukova is synonymized with Nyholmiella obtusifolia. Orthotrichum vittii is excluded from the Russian moss flora. Description of O. dagestanicum is amended. Fifty four currently recognized species from 9 genera of the Orthotrichaceae are presently known to occur in Russia; list of species with common synonyms and brief review of distribution in Russia is presented. Numerous problematic specimens with unresolved taxonomy were omitted for future. Revealed taxonomical inconsistencies in the genera Zygodon, Ulota, Lewinskya, Nyholmiella, Orthotrichum are briefly discussed. Main regularities of spatial differentiation of the family Orthotrichaceae in Russia are considered. Recently presented novelties contribute to the certain biogeographic pattern, indicating three different centers of diversity of the family, changing along longitudinal gradient. Unlike European one, continental Asian diversity of Orthotrichaceae is still poorly known, the Siberian specimens which were previously referred to European species in most cases were found to represent other, poorly known or undescribed species. North Pacific Region houses peculiar and poorly understood hot spot of diversity of Orthotrichoid mosses. Thus, these hot spots are obligatory to be sampled in course of revisions of particular groups, since they likely comprise under-recorded cryptic- or semi-cryptic species. Latitudinal gradient also contributes to the spatial differentiation of the revealed taxonomic composition of Orthotrichaceae.

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