Ashfall Blankets Lecture #7 Fall 2009 Ashfall Class

AVO Photo: Kate BullRedoubt ashfall

Anchorage ashfall from Crater Peak/Spurr 1992 (AVO photo)

1992 Crater Peak SpurrAVO photos

MODIS 12 May 2008 Chaiten fallout blanket

Bonadonna & Houghton, 2005, BV 67: 441-456

Bonadonna & Houghton, 2005, BV 67: 441-456

Bonadonna & Houghton, 2005, BV 67: 441-456

Bonadonna & Houghton, 2005, BV 67: 441-456

Overall the Fuego subplinian eruptions have only a few percent of the fine mode, which appears to come from the pyroclastic flow milling. Larger plinian eruptions likely have a much higher proportion of co-PF ash.

Rose et al., 2007 BV, in press

Fine mode is located to WNW, while the bulk of the coarse ash is W to WSW

HYSPLIT shows that 4 km winds are to WNW while winds at 8-12 km are W and WSW

Voronoi TesselationBonadonna & Houghton, 2005

Crater Peak/Spurr, Sept 1992Andesite, Sub-plinian

Total GSD