Mammoth Cave National Park

Mammoth Cave National Park

Earthquakes

Mammoth Cave lies 150 miles from a major earthquake fault along the Mississippi River. In 1811 and 1812, a series of three earthquakes with estimated magnitudes of 8.6, 8.4 and 8.7 on the Richter Scale struck the Midwest. In the cave, saltpeter miners reported that... "about five minutes before the shock a heavy rumbling noise was heard coming out of the cave like a mighty gust of wind; when that ceased, the rocks cracked, and all appeared to be going in a moment of final destruction. However, no one was injured although large rocks fell in some parts of the cave."

Geologists believe that the effects of earthquake tremors are less in caves than on the surface. The shock waves that would have the most potential to cause damage to caves actually do very little because they are unable to travel through a gaseous medium—that is, the air in the cave. The force arrives at the cave wall, displaces the air and is absorbed with relatively little effect.