Renowned volcanologist...

passes away: Geologist Dwight Crandell dead at 86

. He's probably best known for this work:

Crandell, D.R., and Mullineaux, D.R., 1978, Potential Hazards from Future Eruptions of Mount St. Helens Volcano, Washington -- USGS Bulletin 1383-C, 26 p.

I participated in a field trip to Mount St. Helens with him in 1984 and found him to be a consummate field geologist.