Fractures models comparison using GIS data around crater lakes in Cameroon volcanic line environment
Explore the source record for details and available documents.
SEARCH · Engineering Papers
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Side-looking radar photography for mapping geologic and topographic features
Preferred classification of calderas and volcano- tectonic depressions based on relative amounts of lava and proclastic ejecta
Fe content of clinopyroxene in basalt-basaltic andesite-andesite-latite of Mogollon Plateau /New Mexico/
Pyroclastic ejecta and the deposits they form were classified in many ways, and many interpretations were given to individual terms. Some classifications are based on the modes of orgin and deposition of the ejecta; others emphasized the chemical and physical composition of the ejecta. Particle-size was used as the prime basis of subdivision, and the same size-limits were used as those employed in the classification of sediments and sedimentary rocks.
A classification of maars, tuff-rings, tuff-cones, and diatremes is given along with a summary of their lithologic and structural characteristics at the surface and at depth, and their probable manner of formation. Particular emphasis is placed on the roles of fluidization and groundwater.
A new indirect approach to crustal analysis of a specific sector of the Ethiopian plateaus and rift is discussed. It is suggested that progressive changes in basalt chemistry across this area are related to crustal thinning and shallowing of the zone of melting under the Afar rift.
Surface features on the flanks of Martian shield volcanoes photographed by Mariner 9 are identified as lava flow channels, rift zones, and partly collapsed lava tubes by comparisons with similar structures on the flanks of Mauna Loa shield volcano, Hawaii. From these identifications, the composition of the Martian lava flows is interpreted to be basaltic, with viscosities ranging from those of fluid pahoehoe to more viscous aa.
Probable causes, distributions, and nature of fracture patterns of Type 3 craters around the margins of major maria are investigated.
Explore the source record for details and available documents.
A theory of transport of gases emanating from a source on the lunar surface is developed, in which the distribution of a gas is given by the convolution of the time and space description of its source with a Green's function. Green's functions that represent the impulsive response of vertical and horozontal components of particle flux at the lunar surface are derived. The characteristics of these functions and their dependence on the nature of encounters of gas molecules with the lunar surface are discussed in detail.
There are no author-identified significant results in this report.
The behavior of volcanoes was studied by geologic mapping, petrologic investigations of lava and xenoliths, physical measurements, and theoretical modelling. Field observations were conducted in Alaska (Nunivak Island), Iceland, Hawaii (Mauna Kea), Italy (Etna, Stromboli), and Arizona. The results are discussed and compared with known data for lunar and planetary gelogy. Field methods used for the volcano research are cited and a list is given of all participating scientists and students. Publications and abstracts resulting from the research are also listed.
The ERTS Data Collection System makes it feasible for the first time to monitor the level of activity at widely separated volcanoes and to relay these data rapidly to one central office for analysis. While prediction of specific eruptions is still an evasive goal, early warning of a reawakening of quiescent volcanoes is now a distinct possibility. A prototypical global volcano surveillance system was established under the ERTS program. Instruments were installed in cooperation with local scientists on 15 volcanoes in Alaska, Hawaii, Washington, California, Iceland, Guatemala, El Salvador and Nicaragua. The sensors include 19 seismic event counters that count four different sizes of earthquakes and six biaxial borehole tiltmeters that measure ground tilt with a resolution of 1 microradian. Only seismic and tilt data are collected because these have been shown in the past to indicate most reliably the level of volcano activity at many different volcanoes. Furthermore, these parameters can be measured relatively easily with new instrumentation.
There are no author-identified significant results in this report.