I find myself somewhat pressed to mention here that seismic activity at Yellowstone has been somewhat more than normal of late. This seemed to begin with a large long period event 4 days ago on the 11th, and it seems to have progressed from there to a point of greater than usual seismic activity, which today seems a bit pronounced. The event of the 11th is seen here:
Events of this type show building pressure, and as this type event goes it’s a pretty big one. This was recorded strongest 70 miles northeast of Yellowstone, at Red Lodge Montana, but also showed up elsewhere, north of the park. That was four days ago. Today more unusual seismic activity is showing up at seismograph stations within the park.
The park station closest to the Red Lodge seismograph is the YPK station easternmost in the park, and on that one this evening we see:
This was before the 4.3 quake in Alaska that showed up all over the place. It was a mag 2.4 quake at the east end of the park. Okay, that’s where the long period event was, in that overpressured and saturated fracture zone. This is not worrisome by itself, but elsewhere, at the YMR station on the west side of the park we see continuous and sustained tremor.
I’ve really not seen that at Yellowstone before, and coming after the long period event of the 11th it concerns me. This tremor seems localized to the west side of the park and appears to a lesser degree at the YFT station to the south, which also caught the event on the YPK station. This is more seismicity than I am used to seeing there. We do not as yet see repeated long period events and certainly not of the size and magnitude of the one seen on Sept. 11th, but the situation bears watching in my estimation.
I find that the YMR station recording the seismic activity shown above is located close to three hydrothermal features at the park, those being the Lower Geyser Basin, the Midway Geyser Basin, and the Upper Geyser Basin. So, the activity we see above at the YMR station might very well be hydrothermal in nature. Still it is pronounced activity and greater than usual. It might be a symptom of rising magma but it’s just too early to say at this point. It’s also perhaps worth noting the YMR and YMT seismographs are right near a fracture zone in the caldera, which also would seem to be under pressure.
I’d really like to have current InSAR data for ground uplift there, but they don’t just pass that out to everyone and it’s not a daily thing you can find on the web with the weather reports.
One of the little inconveniences of monitoring seismographs for a given area popped up last night. While I was following the seismographs outside Yellowstone for indications of what might be going on around there a 7.3 quake hit in the south Pacific and scribbled all over the seismographs everywhere. This followed a 3.7 in the Aleutians that went on for quite a while, and also messed things up.
Drat! Would that I could write to the Bureau of Earthquake management and have them reschedule those things. Unfortunately we do not as yet have an earthquake czar, and quakes continue to occur as they please.
Things appear seismically quiet at Yellowstone this morning both inside and outside the park, which is nice. It may get noisy again there over the coming days, but for now it appears relatively peaceful at the world’s best known super-volcano. This is a good thing.
I’ll continue to monitor what’s going on there as best I can, and I know others reading here will be doing the same.
Looking at the Pacific Northwest I see that things are also quieter there, with Rainier having gotten quieter overnight, showing it’s usual minor background seismicity again. Nothing exciting at St. Helens this morning either.
Seismic activity seems to be resuming in the area of the hydrothermal basins at Yellowstone with the YMR station there showing us this:
I’m guessing this is hydrothermal activity localized to the geyser basins near the station there. At the far east end of the park the YPK station shows just one little blip for the day, and other stations around YMR show nothing much. Seismographs outside the park at Bozeman, Pinedale, Red Lodge, and Missoula are totally quiet.
I will be updating this post as events progress, keep checking back.