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Analysis of radar images of the active volcanic zone at Krafla, Iceland: The effects of look azimuth biasingThe geomorphic expression of Mid-Ocean-Ridge (MOR) volcanism in a subaerial setting occurs uniquely on Earth in Iceland, and the most recent MOR eruptive activity has been concentrated in the Northeastern Volcanic Zone in an area known as Krafla. Within the Krafla region are many of the key morphologic elements of MOR-related basaltic volcanism, as well as volcanic explosion craters, subglacial lava shields, tectonic fissure swarms known as gjar, and basaltic-andesite flows with well developed ogives (pressure-ridges). The objective was to quantify the degree to which the basic volcanic and structural features can be mapped from directional SAR imagery as a function of the look azimuth. To accomplish this, the current expression of volcanic and tectonic constructs was independently mapped within the Krafla region on the E, W, and N-looking SAR images, as well as from SPOT Panchromatic imagery acquired in 1987. The initial observations of the E, W, and N images indicates that fresh a'a lava surfaces are extremely radar bright (rough at 3 cm to meter scales) independent of look direction; this suggests that these flows do not have strong flow direction related structures at meter and cm scales, which is consistent with typical Icelandic a'a lava surfaces in general. The basic impression from a preliminary analysis of the effects of look azimuth biasing on interpretation of the geology of an active MOR volcanic zone is that up to 30 percent of the diagnostic features can be missed at any given look direction, but that having two orthogonal look direction images is probably sufficient to prevent gross misinterpretation.
Document ID
19900003118
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Garvin, J. B. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Williams, R. S., Jr. (Geological Survey Reston, VA., United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1989
Publication Information
Publication: Lunar and Planetary Inst., Abstracts for the Venus Geoscience Tutorial and Venus Geologic Mapping Workshop
Subject Category
Lunar And Planetary Exploration
Accession Number
90N12434
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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