A cikin watanni uku a 1985, an gano ƙananan girgizar ƙasa 3,000 a yankin arewa maso yammacin wurin shakatawa, a lokacin da ake kira girgizar ƙasa, kuma an danganta shi da ƙananan raguwa na Yellowstone caldera. Farawa a ranar 30 ga Afrilu, 2007, ƙananan girgizar ƙasa 16 da girman 2.7 sun faru a cikin Yellowstone Caldera na kwanaki da yawa. Wadannan girgizar ƙasa sun kasance na kowa, kuma akwai irin wannan nau'i 70 tsakanin 1983 da 2008. A watan Disamba na 2008, an auna girgizar ƙasa sama da 250 a cikin kwanaki hudu a ƙarƙashin Yellowstone Lake, mafi girma auna girman 3.9. A Janairu 2010, an gano girgizar ƙasa sama da 250 a cikin kwanaki biyu.
fiye da 250