University of Utah Seismographic Stations is reporting a troubling swarm of earthquakes taking place under Yellowstone Lake.
The actual verbiage of the press release is, "notable swarm," but if you look at the actual seismograph output from the north and central sections of the lake, I think you'll agree that the colors are very pretty and there is alot of each of them.
Here is the link to the online seismographs (updated daily). The key seismographs are YTP and LKWY (EHZ_WY are always suffixed on the ID's of Yellowstone's seismographs).
Things seem to be slowing down in the last 24 hours...which may or may not continue, but my gut tells me that we'll be okay a little longer. The magma chamber continues to fill at Yellowstone and its 8 known volcanic vents. Over time, the longer we go without a serious release of pressure from the magma chamber, the more horrendous the eventual eruption may prove to be.
Ash studies of the eruptions at the Yellowstone Caldera have ranged from as small as two or three states, to as large as 2/3 of the continental United States. It should be noted, however, that the eruptions from this caldera have coincided with the last three planetary ice ages.