نتایج جستجو برای: lava
تعداد نتایج: 2954 فیلتر نتایج به سال:
The conventional K-Ar dating method was applied to the 1986 dacite flow from the new lava dome at Mount St. Helens, Washington. Porphyritic dacite which solidified on the surface of the lava dome in 1986 gives a whole rock K-Ar “age” of 0.35±0.05 million years (Ma). Mineral concentrates from the dacite which formed ins 1986 give K-Ar “ages” from 0.34±0.06 Ma (feldspar-glass concentrate) to 2.8±...
MOTIVATION As the volume of next-generation sequencing (NGS) data increases, faster algorithms become necessary. Although speeding up individual components of a sequence analysis pipeline (e.g. read mapping) can reduce the computational cost of analysis, such approaches do not take full advantage of the particulars of a given problem. One problem of great interest, genotyping a known set of var...
Areas ofvegetation mortality have been recognized in the upland forests of the Kaimai Ranges, North Island, New Zealand. The mortality is not confined to any particular vegetation type, but occurs above a critical altitude that differs at different points along the ranges. The mortality is episodic and has occurred at intervals over a period of several hundred years, with severe droughts implic...
Introduction: The High Resolution Stereo Camera (HRSC) onboard ESA's Mars Express (MEX) orbiter [1] has provided 12.5 m/pixel projected images for a north-south transect of the four major Tharsis shield volcanoes. These data provide an unprecedented opportunity to examine lava flows at high resolution with regional context. Our objective is to characterize late-stage effusive processes and iden...
Introduction: The acquisition of image data from the Mars Odyssey THermal EMission Imaging System (THEMIS) and the European Space Agency’s Mars Express High Resolution Stereo Camera (HRSC) have enabled new observations, and in some cases interpretations, of small volcanic features in the Tharsis region of Mars. While image resolution limitations have traditionally hampered detailed inspection o...
PURPOSE All-ceramic crowns are subject to fracture during function. To minimize this common clinical complication, zirconium oxide has been used as the framework for all-ceramic crowns. The aim of this study was to compare the fracture strengths of two computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia crown systems: Lava and Digident. MATERIALS AND METHODS Twenty Lava CAD/...
Over two hundred isolated outcrops of horizontally stratified, basaltic lava flows within the inner gorge of western Grand Canyon indicate that several natural “lava dams” blocked the flow of the Colorado River during the Pleistocene, resulting in the formation of several lakes within the canyon. The largest lake was 90 m above the high water level of present-day Lake Powell and backed up a dis...
SO2 emission rates from Erebus volcano show periodicity, which directly relates to lava lake convection and magma and conduit processes. Mt. Erebus is a 3794 m stratovolcano with a persistently degassing convecting, phonolite lava lake. Lava lake SO2 emission rates were collected from 1992 to 2003 using the correlation spectrometer (COSPEC) and in 2003 and 2005 using a miniature ultra-violet di...
Timely predictions of the areas likely to be inundated by lava flows are of major interest to hazard managers during a volcanic eruption. To this aim several models have been developed, which deal with various aspects of flow emplacement and cooling. That challenge has inspired the INGV-CT to develop the MAGFLOW Cellular Automata model to simulate lava flows [6]. It is based on a steady state s...
Terrestrial planetary bodies such as Mars and the Moon are known to harbor volcanic terrain with enclosed lava tube conduits and caves. The shielding from cosmic radiation that they provide makes them a potentially hospitable habitat for life. This motivates the need to explore such lava tubes and assess their potential as locations for future human outposts. Such exploration will likely be con...
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