For pre-historic eruptions, this scale is calculated based upon the dispersal of the volcanic products- i.e. how far and wide they are scattered. Volcanic eruptions that have very tall columns will spread tephra far and wide.
created by Mery Molenaar, [email protected]
last modified: September 13, 2000
URL: http://www.geocities.com/mery_molenaar/volc/height.html