"Ice Build-up" Responsible for Recent Yellowstone Quakes Official Explanation
Stan's short and to the point comment: "I'm not so sure I buy this..."
February 18, 2011
This is the "official" response given to a Millennium-Ark reader when she queried USGS the "disappearing Yellowstone earthquakes. This is interesting especially in light of the 57-quake swarm just last month shown on their own data pages. Forecast: "swarming" last month; "denying" this month.
There was not a M3.8 in Yellowstone this morning. Recent ice buildup on the University of Utah's seismic network at Yellowstone has caused data-transmission problems and many, many false earthquakes. An explanation of the problem is on our website (volcanoes.usgs.gov/yvo).
The automated system is programmed to post earthquakes it detects onto the public University of Utah webpage and onto the USGS site as well. From there, it gets picked up by other webpages around the world. In this case, the earthquake never occurred (obvious on the webicorder pages that show the waveforms), and so they are manually deleted by seismologists. Some other pages may not reflect the deletion, but the USGS and Utah websites are correct.
Because of the problems, the automatic locations have been temporarily halted as of this afternoon. Earthquakes will now only appear once they have been verified by a seismologist. This should minimize the confusion. Engineers are trying to fix the problem, but it may be some time before it is completely resolved.
Jake Lowenstern, USGS and Yellowstone Volcano Observatory