'A'a lava

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Lumps of ʻAʻā lava after an eruption of Puʻu ʻŌʻō in June 1983
ʻAʻā lava flow at Kīlauea
Block lava field on Mt Cameroon

'A'ā Lava [ ʔɑʔɑː ] or Brockenlava (sometimes also: Zackenlava ) is different from the lava Types The zähflüssigste form. The name comes from the Hawaiian language and was introduced into geological terminology by Clarence Dutton . It means burning, fiery, stony . In Iceland the Brocken lava is called apalhraun .

During the solidification and partial crystallization of the melt flow, its crust breaks and leaves a surface that is interspersed with sharp-edged, irregularly shaped, jagged lumps and clods .

Compared to Pāhoehoe lava , ʻAʻā lava flows more slowly and is cooler; it is often located in the lower part of thin lava flows, because outgassing and cooling increase the viscosity . At the end of the stream it forms a steep front.

See also


  • Clarence Edward Dutton: Hawaiian volcanoes . IN: US Geological Survey annual report of the director , Vol. 4, 1882/83, Washington 1884, pp. 81-219. WorldCat

Web links

Commons : Aa lava  - collection of images, videos and audio files

Individual evidence

  1. Sometimes also written Aa-Lava for simplicity . See: Volcanic rocks (volcanic rocks): Brockenlava (Aa-Lava) , klett.de
  2. a b ʻaʻā in Hawaiian Dictionaries
  3. James Furman Kemp: A handbook of rocks for use without the microscope: with a glossary of the names of rocks and other lithological terms . 5th ed., New York: D. Van Nostrand, 1918, pp. 180 , 240 : CE Dutton, 4th Annual Report US Geological Survey , 1883, pp. 95; Bulletin of the Geological Society of America, Volume 25 / Geological Society of America. 1914, p. 639
  4. Forms of magmatic rocks: AA - BROCKENLAVA - APALHRAUN ( Memento from July 8, 2009 in the Internet Archive ), bakip-linz.at
  5. volcanism at wetter-observer.de, (PDF file)