Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1985-1989  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of volcanology 51 (1989), S. 415-432 
    ISSN: 1432-0819
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract This paper presents a new method of analysing lava flow deposits which allows the velocity, discharge rate and rheological properties of channelled moving lavas to be calculated. The theory is applied to a lava flow which was erupted on Kilauea in July 1974. This flow came from a line of fissures on the edge of the caldera and was confined to a pre-existing gully within 50 m of leaving the vent. The lava drained onto the floor of the caldera when the activity stopped, but left wall and floor deposits which showed that the lava “banked up” as it flowed around each of the bends. Field surveys established the radius of curvature of each bend and the associated lava levels, and these data, together with related field and laboratory measurements, are used to study the rheology of the lava. The results show the flow to have been fast moving but still laminar, with a mean velocity of just over 8 m s−1; the lava had a low or negligible yield strength and viscosities in the range 85–140 Pa s. An extension of the basic method is considered, and the possibility of supercritical flow discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Earth, moon and planets 44 (1989), S. 219-231 
    ISSN: 1573-0794
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract It has been proposed that divergence and crustal spreading occur in Western Aphrodite Terra and some adjacent equatorial regions of Venus at rates in the range of a few centimeters per year. If equatorial spreading is common and widespread, then a consequence of this should be: (1) a young average age of the surface of the planet, (2) a trend in age from older terrain in the polar regions to younger terrain toward the equator, and (3) a latitudinal distribution of extensional features in equatorial regions and compressional deformation features in middle to high latitudes. These predictions are tested using published results from Arecibo, VENERA 15/16, and Pioneer Venus data, and it is found that: (1) the northern mid-to-high latitudes are characterized by a young average age, (2) there is a trend in the total number of craters per unit area from high values in the north polar regions to low values toward the equator, and (3) there is evidence for a latitudinal distribution of tectonic features of different types, with extensional features common in equatorial regions and compressional deformation features common in the northern middle to high latitudes. Further tests of these and other predictions can be made using data from the upcoming Magellan mission.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...