Bulletin Volcanologique

, 46:277 | Cite as

Flow directions inferred from imbrication in the Handa pyroclastic flow deposit in Japan

  • H. Kamata
  • K. Mimura


Flow direction patterns have been determined by imbrication measurements of pumice and lithic fragments of the Handa pyroclastic flow deposit, in order to estimate the source vent location and to analyze the flow behavior. The pyroclastic flow deposit studied is dacitic in composition, 2 km2 in volume, and >32,300 Y.B.P. in age. Flow directions from 52 outcrops indicate a source vent located within the area of recent lava domes of Kuju Volcano. The distribution of the pyroclastic flow deposit and the flow direction patterns determined by imbrication suggest that the pyroclastic flow accurately followed the topographic relief at the time of eruption. The presence of imbrication indicates the change of flow-regime from turbulent condition to laminar condition according to the distance from the source vent. Imbrication is visible within the lower-half reaches of the pyroclastic flow distribution, where the pyroclastic flow had developed the laminar flow characteristics of a dense gravity current.


Flow Direction Pyroclastic Flow Flow Deposit Error Angle Lava Dome 
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  1. Aramaki, S., 1957,Classification of Pyroclastic Flows. Bull. Volc. Soc. Japan, 2nd ser.,1, p. 47–57 (in Japanese). (English translation; 1961, International Geology Review,3, p. 518–524).Google Scholar
  2. Bates, R. L. andJackson, J. A., 1980, «Imbrication (sed) ». In:Glossary of Geology (p. 312), 2nd ed., American Geological Institute, Falls Church, Virginia, U.S.A..Google Scholar
  3. Elston, W. E. andSmith, E. L., 1970,Determination of Flow Direction of Rhyolitic Ashflow Tuffs from Fluidal Textures. Geol. Soc. America Bull.,81, p. 3393–3406.CrossRefGoogle Scholar
  4. Kamata, H. andMimura, K., 1981,Imbrications and the Flow Directions of the Pyroclastic Flow Deposit from Kuju Volcano, Southwestern Japan. Bull. Volc. Soc. Japan, 2nd ser.,26, p. 281–292 (in Japanese).Google Scholar
  5. Matsumoto, Y., Hayashi, M. andYamasaki, M., 1970,14 C Age of Handa Pyroclastic Flow Deposit of Kuju Volcano. J. Geol. Collabor. Japan,24, p. 190–191 (in Japanese).Google Scholar
  6. Mimura, K. andMacLeod, N. S., 1978,Source Directions of Pumice and Ash Deposits near Bend, Oregon. Geol. Soc. America Cordilleran Sec. Abst.,10, p. 137.Google Scholar
  7. Nakamura, K. andUi, T., 1975,Field Criteria for Flow Vector of Pyroclastic Flow Deposits. Bull. Volc. Soc. Japan, 2nd ser.,19, p. 181 (in Japanese).Google Scholar
  8. Ono, K., 1963,Geology of the Kuju District. Quadrangle Series 1:50,000 Map, Geol. Surv. Japan, 106 p. (in Japanese).Google Scholar
  9. -----,Matsumoto, Y., Miyahisa, M., Teraoka, Y. andKambe, N., 1977,Geology of the Taketa District. Quadrangle Series 1:50,000 Map. Geol. Surv. Japan, 145 p. (in Japanese).Google Scholar
  10. Schmincke, H.-U. andSwanson, D. A., 1967,Laminar Viscous Flowage Structures in Ash-flow Tuffs from Gran Canaria, Canary Islands. J. Geol.,75, p. 641–664.CrossRefGoogle Scholar
  11. Smith, R. L., 1960,Ash Flows. Geol. Soc. America Bull.,71, p. 795–842.Google Scholar

Copyright information

© Intern. Association of Volcanology and Chemistry of the Earth’s Interior 1983

Authors and Affiliations

  • H. Kamata
    • 1
  • K. Mimura
    • 2
  1. 1.Geothermal Research DepartmentGeological Survey of JapanIbarakiJapan
  2. 2.Geology Dept.Geological Survey of JapanIbarakiJapan

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