نتایج جستجو برای: volcanic areas
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Introduction Airborne volcanic ash is a major aviation, health, and infrastructure hazard. When ingested into aircraft engines, volcanic ash can cause engine damage or failure. For example, in December 1989, a 747 jetliner carrying 231 passengers encountered an ash cloud during an eruption of the Mount Redoubt volcano, located southwest of Anchorage, AK. Within 60 seconds of encountering the he...
The 1285 m thick MIS core offers an invaluable opportunity to obtain a detailed record of volcanism in McMurdo Sound. Volcanic stratigraphy and preliminary petrologic data on volcanic rocks in the AND-1B core are reported here. Remarkable volcanic deposits include: a) a phonolitic pumice layer found at ≈85 mbsf which is not correlated to any known vent onshore; b) a black well sorted volcanic s...
although typically small in terms of their spatial footprint, landslide hazards are relativelyfrequent in northern iran. we assess landslide susceptibility for the nearly 20.000 km2 large study area of the urmia lake basin which is dominated by agricultural land use but includes the major settlements areas of the east azerbaijan province, iran. landslide factors are established in form of gis d...
Crustal assimilation (e.g. Hildreth and Moorbath, 1988) and/or subduction erosion (e.g. Stern, 1991; Kay et al., 2005) are believed to control the geochemical variations along the northern portion of the Chilean Southern Volcanic Zone. In order to evaluate these hypotheses, we present a comprehensive geochemical data set (major and trace elements and O–Sr–Nd–Hf–Pb isotopes) from Holocene primar...
Jökulhlaups in Iceland may originate from marginal or subglacial sources of water melted by atmospheric processes, permanent geothermal heat or volcanic eruptions. Glacier-volcano interactions produce meltwater that either drains toward the glacier margin or accumulates in subglacial lakes. Accumulated meltwater drains periodically in jökulhlaups from the subglacial lakes and occasionally durin...
The Neogene–Quaternary volcanic range running along the East Carpathians in Romania, extends from Oaș Mountains, north-west, to South Harghita Mountains and Perșani south-east, as part of broader province Carpathian–Pannonian Region. It resulted intense activity during 15–0.1 Ma time interval, generating huge volumes effusive explosive products a variety edifices primary landforms large composi...
The pyroclastic rocks of "The Crater", South Island, New Zealand belong to the Miocene, alkaline basaltic Dunedin Volcanic Group and represent an individual eruptive center with possible multiple vents. Three pyroclastic units have been separated at the study area based on textural and compositional features as well as their stratigraphic positions. The central part of The Crater comprises basa...
Andean volcanism occurs within the Andean Volcanic Arc (AVA), which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth’s longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These se...
We used thermochemical equilibrium calculations to constrain the oxygen fugacity ( fO2 ) of volcanic gases on Io. Three types of calculations were done: (1) Upper limits for fO2 from Voyager IRIS upper limits for the SO3/SO2 ratio and the O3 abundance in the Loki volcanic plume; (2) lower limits for fO2 from the observed SO/SO2 ratio in Io’s atmosphere; (3) oxygen fugacities as a function of te...
Silicic volcanic rocks are associated with most, if not all, continental ×ood basalt provinces and volcanic rifted margins, where they can form substantial parts of the eruptive stratigraphy and have eruptive volumes >104 km3. Poor preservation of silicic volcanic rocks following kilometer-scale uplift and denudation of the volcanic rifted margins, however, can result in only deeper level struc...
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