| |
| | CVO Website - Sarna-Wojcicki, et.al., 1981, Areal Distribution, Thickness, Mass, Volume, and Grain Size of Air-Fall Ash ... (Site not responding. Last check: 2007-11-06) |
 | | The average vertical rate of ascent of the column between 0838 and 0842 is 44 meters per second, or about 160 kilometers per hour. |
 | | Because the 250-kilometer per hour velocity represents an average over the first 13 minutes, and because the plume-front velocity decreased after the first 13 minutes, velocities of the expanding ash cloud in the first few minutes of the eruption must have been much greater. |
 | | Average velocities of the ash-plume front over the first 13 minutes, as calculated from satellite photographs, were only about 220 kilometers per hour in the direction of the prevailing wind, about 185 kilometers per hour northward, about 150 kilometers per hour northwestward, and zero to the south and southwest. |
| vulcan.wr.usgs.gov /Volcanoes/MSH/Publications/PP1250/SarnaWojcickiOthers2/ash_may18.html (1095 words) |
|