Filters: Tags: Volcanic Ash (X) > Date Range: {"choice":"year"} (X)
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A total of 100 samples were collected from two proximal sections of Keanakākoʻi, Tephra unit D deposits. Samples were analyzed on Microtrac CAMSIZER® P4 and X2 instruments for grain size and shape data in the USGS Hawaiian Volcano Observatory (HVO) tephra lab. Data release includes sample descriptions, half phi grain size distributions, and statistical output from DECOLOG deconvolution modeling of grain size distributions. Grain size is reported using the sieve compatible Xcmin parameter (CAMSIZER® manual, 2020). Data of 2D shape parameter means of sphericity, Krumbein roundness and compactness of samples as well as for half phi grain size bins at 4, 3, 2, 1, 0, and -1 phi are also included. Please refer to associated...
Categories: Data;
Tags: Camsizer,
Grain shape,
Grain size,
Hawaii Volcanoes National Park,
Kīlauea Volcano,
This data collection includes ground-penetrating radar (GPR) data and related observations collected from the NASA Goddard Instrument Field Team (GIFT) Expedition to the Icelandic Highlands in July-August 2019 and August 2021. This dataset includes observations at the Askja Volcano and caldera and Vikrahraun lava flow. GPR data were collected using Geophysical Survey Systems, Inc (GSSI) shielded bistatic antennas at center frequencies of 200 MHz, 400 MHz, and 900 MHz. Common offset surveys were conducted to investigate the subsurface interfaces. The GPR data includes raw data obtained from the instrument (as GSSI .dzt files), line shapefiles of survey locations, and interpreted ice thickness GeoPackage files with...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Askja,
Iceland,
USGS Science Data Catalog (SDC),
Volcanic ash,
caldera,
The Blue Ridge belt in northwestern North Carolina and northeastern Tennessee is composed chiefly of 1,000-million to 1,100-million-year-old metamorphic and plutonic rocks that have been thrust many miles northwestward across unmetamorphosed Cambrian(?) and Cambrian sedimentary rocks of the Unaka belt. The Blue Ridge thrust sheet is rooted on the southeast along the Brevard zone, a zone of strike-slip faulting along which metamorphic and plutonic rocks of the Inner Piedmont belt are juxtaposed with rocks of the Blue Ridge. Near the southeastern edge of the Blue Ridge belt, the Blue Ridge thrust sheet is breached by erosion, and the rocks beneath are exposed in the Grandfather Mountain window, which is 45 miles long...
These data are presented to geochemically characterize glass from the informally named Khonkho tephra, an ashfall deposit that crops out at the Khonkho Wankane archaeological site in Jesus de Machaca, Bolivia. The Khonkho tephra appears to have been emplaced by a major explosive eruption from a currently unknown volcanic source. The unit forms a marker bed at an archaeologically important stratigraphic level. These data are to accompany a publication that describes the tephra-fall deposit and its implications and will eventually be used to correlate the unit to samples from other locations where it crops out and to identify its source volcano and eruption. Any use of trade, firm, or product names is for descriptive...
Categories: Data;
Tags: Archaeology,
Bolivia,
Geochemical analysis,
Geochemistry,
Glass composition,
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