As earthquakes go, it wasn't really something to worry about but hey, something to discuss rather than the weather.
There was a magnitude 3.5 earthquake (Richter Magnitude Scale) in the Black Hills 2:43 a.m., Thursday. The U.S. Geological Survey put the epicenter of the quake 16 kilometers or a little more than nine miles east-northeast of Custer and about five kilometers or three miles deep. There are no reports of injuries or damage, other than some picture frames falling off walls. Some people told KOTA Territory News they thought it was a plane crash or a meteor.
The 3.5 magnitude Black Hills quake, according to the USGS, could have been felt by a lot of people; but as some noted, they might not realize it was a quake. The vibration is about the same as feeling a truck pass by. It is not a structurally damaging quake. Click here for comparisons with more intense quakes.
Earthquakes are not uncommon in western South Dakota. According to the USGS, most of the country east of the Rocky Mountains has infrequent quakes. Oddly enough, a small quake east of the Rockies can be felt over an area 10 times larger than a similar magnitude quake in the west. Thursday morning's 3.5 magnitude quake could possibly have been felt about 50 miles away.
The largest quake in South Dakota was a 4.5 magnitude in 1911, centered near Huron. South Dakota has never had a death attributed to an earthquake.