There seems to be a lot of panic mongering following this article around, so i'm going to copy and paste a post I made on this very topic on another forum.
Magma Movement = Harmonic Termors.
Nowhere in the articles are Harmonic Tremors mentioned.
Yellowstone is in a tectonically active area, and experiences something like 1000-2000 earthquakes per year. Earthquake swarms like this are not unheard of in this area. There was an event in 1985 where over 3000 over a period of several months. There have also been 70 earthquake swarms in the period 1983-2008.
Further, there was no eruption from Yellowstone 70,000 years ago. The eruption that occurred 70,000 years ago was from Lake Toba in Indonesia (Sumatra). The Lake Toba eruption was nearly 3 times bigger than the last Yellowstone eruption which occured 640,000 years ago, and in terms of volume ejected only barely qualifies as VEI 8.
There have been several larger eruptions than the most recent magmatic eruption at Yellowstone, 640,000 years ago.