نتایج جستجو برای: volcanic
تعداد نتایج: 14735 فیلتر نتایج به سال:
In this paper, we present some physical models that can describe the ascent of volcanic ash into the atmosphere during a volcanic eruption. We consider both sustained volcanic eruption columns and discrete volcanic thermal clouds. To test the modeling approach, we compare our predictions of the ascent rate of a model cloud with some observations of the ascent of the ash cloud during the April 1...
Volcanic activity is observed worldwide with a variety of ground and space-based remote sensing instruments, each with advantages and drawbacks. No single system can give a comprehensive description of eruptive activity, and so, a multi-sensor approach is required. This work integrates infrared and microwave volcanic ash retrievals obtained from the geostationary Meteosat Second Generation (MSG...
Delineating boundaries of volcanic edifices from surrounding topography is often difficult, timeconsuming and subjective. For large volcanic fields, with hundreds of volcanoes, developing methods to efficiently and consistently identify and isolate volcanoes from surrounding topography is of utmost importance. Advances in technology for collecting and processing digital elevation datasets have ...
Major systems of northwesterly, northerly, and northeasterly trending recurrilig fractures or faults controlled emplacement of various units of the Iron Mask batholith. The batholith was emplaced in a high level volcanic to subvolcanic environment, comagmatic with Nicola volcanic rocks and coeval with part of the upper Nicola succession. The batholith intruded volcanic and sedimentary rocks of ...
Experiment is central to scienti¢c methodology. Within science in general, experiments are used for four primary purposes, i.e. as a tool to explore novel phenomena and to provide systematic observations of processes, to determine the values of key parameters, to test hypotheses and theoretical models, and to validate computational models, which themselves can be considered as numerical experim...
The Mount Meager volcanic complex in southern British Columbia is snow and ice covered and has steep glaciated and unstable slopes of hydrothermally altered volcanic deposits. Three large-volume (>108 m3) volcanic debris flow deposits derived from the Mount Meager volcanic complex have been identified. The volcanic debris flows travelled at least 30 km downstream from the volcanic complex and i...
Part 1 of this paper is concerned with various types of deformation of volcanic cones as listed in Table 1. In regard to the crustal displacements before and after eruptions, the local upheaval and fracturing near crater remain as a permanent deformed topography, but the areal upheaval and subsidence before and after eruption are believed to be a reiterative movement caused by increase and decr...
The Eocene volcanic rocks exposed in the NW Sechangi area of Lut block, include pyroclastic deposits and lavas. These volcanic rocks are basalt, basaltic andesite, andesite, andesite-trachyandesite, trachydacite, dacite and rhyolite-ignimbrite in composition. Based on our field observations, the volcanic rocks erupted in four stages in the aquous to subaerial environments. The volcanic rocks ar...
The Paleogene volcanic rocks of Damash have a considerable outcrops in Alborz structural zone in Guilan Province. These volcanic rocks show a compositional range from olivine basalt, basaltic andesite, pyroxene andesite to andesite. The petrographical and geochemical studies indicate that the fractional crystallization of clinopyroxene and olivine play an important role in lithological varietie...
[1] Volcanic mound fields identified on SeaMARC II and HMR1 12 kHz side-scan data from the southern East Pacific Rise (SEPR) occur near overlapping spreading centers (OSCs) and migration traces of OSCs. The volcanic mound fields appear as a distinctive hummocky seafloor fabric due to side-scan backscatter reflections from clusters of moundshaped reflectors. The lack of growth of the mound field...
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