Missouri and Volcanoes
Q. Is there evidence of volcano calderas in Missouri? A. "The St. Francois Mountains is a region of formerly extentive [sic] volcanic terrane comprising several calderas, cauldron subsidence structures, ring intrusions, and resurgent cauldrons. Three calderas are recognized: the Taum Sauk, the Butler Hill, and the Hawn Peak [sic] [i.e., Hawn Park]" -- https://mrdata.usgs.gov/geology/state/sgmc-unit.php?unit=MOpCAv%3B0
Q. Are any of Missouri calderas still capable of producing an eruption? A. No.
"“The best known caldera is at Yellowstone. It is 35 miles by 25 miles,” Seeger said. “Right here, we’re on the edge of the Taum Sauk caldera, which is about 12 miles in diameter.” Unlike Hawaiian volcanoes that spew liquid lava, calderas erupt explosively. “Think Mt. St. Helens, only huge,” Seeger related. “If you think of St. Helen’s (eruption) as the size of an espresso cup, Yellowstone was a 50-gallon bag and ours was a 30-gallon bag.” -- Cheryl Seeger, geologist for the Missouri Department of Natural Resources (DNR).
"An earthquake is the rapid release of energy stored along a fault. A fault is an opening, or crack, in the earth that has experienced differential movement from one side to the other."-- Gary Patterson, Geologist, The University of Memphis, Center for Earthquake Research and Information, CERI Director of Education and Outreach. Email dated 4/30/2015.
'Aftershocks are earthquakes that follow the largest shock of an earthquake sequence. They are smaller than the mainshock and within 1-2 rupture lengths distance from the mainshock. Aftershocks can continue over a period of weeks, months, or years. In general, the larger the mainshock, the larger and more numerous the aftershocks, and the longer they will continue." -- http://earthquake.usgs.gov/learn/glossary/?term=aftershocks