Busy day so I probably won't get to update much as we're busy hosting Dr. Charlie Bacon, geologist for the USGS, here at UC Davis today. Dr. Bacon has written some seminal papers in his career and is probably the foremost authority of the evolution of Crater Lake/Mt. Mazama (speaking of which, >a new geologic map for the Park was recently released) and the caldera-forming eruption. He's also a really nice guy.
If you want to read some of his papers, you might try these:
Bacon, C.R., Implications of silicic vent patterns for the presence of large crustal magma chambers, in: D.P. Hill, R.A. Bailey, A.S. Ryall, M.L. Jacobsen, (Eds), Proceedings of Workshop XIX; Active tectonic and magmatic processes beneath Long Valley Caldera, eastern California. Open-File Report - U. S. Geological Survey, U.S. Geological Survey, 1984, pp. 830-850.
Bacon, C.R., Gardner, J.V., Mayer, L.A., Buktenica, M.W., Dartnell, P., Ramsey, R.W., Robinson, J.E., 2002. Morphology, volcanism, and mass wasting in Crater Lake, Oregon, GSA Bulletin. 114, 675-692.
Bacon, C.R., Persing, H.M., Wooden, J.L., Ireland, T.R., 2000. Late Pleistocene granodiorite beneath Crater Lake caldera, Oregon dated by ion microprobe, Geology. 28, 467-470.
Anyway, I thought I'd add a couple of teases today, sent in by my friend Dr. Ed Kohut. Feel free to add your interpretation in the comments.
I'll try to comment on these later when things settle down.