SIOUX FALLS, S.D. (KELO)– South Dakotans have experienced the earth shaking from five different earthquakes since the start of 2021, according to the United States Geological Survey.
On Wednesday, the fifth earthquake of the year was recorded, happening 15 km North Northeast of Quinn. This was reported to be a 2.6 magnitude earthquake.
KELOLAND meteorologist Scot Mundt said the cause of earthquakes in South Dakota is that years ago, during the Ice Age, a large glacier covered our land.
“Well, that put a lot of weight on the earth and it compressed the earth,” Mundt said. “That glacier is no longer around so the earth is now free to expand and that’s the main reason why we do get earthquakes here in South Dakota.”
Usually, South Dakota sees about two earthquakes every three years on average, Mundt said.
“Its a little bit above average right now, who’s to say we won’t get another one this year, and who’s to say we won’t see another one for maybe the next couple years,” he said. “A lot of unknown goes into when earthquakes do occur.”
The first one reported this year was a 3.1 magnitude earthquake 5 km North of Tyndall on January 4.
There was another one reported 10 km E of Edgemont on March 26, which recorded at 3.4 magnitude.
On the South Dakota- Nebraska border, the third earthquake was recorded, 10 km NE of Anoka, Nebraska, reached a magnitude of 3.7 on June 4. On that same day, the forth one of the year was reported, 9 km East-Northeast of the same Nebraska town and it reached a 3.1 magnitude.
In 2020, there were only two earthquakes recorded: a 3.2 magnitude quake 10 km North- Northwest of Bowdle on December 9 and a 2.5 magnitude on August 25 10 km North of Platte.
South Dakota’s earthquake magnitudes are not very high, Mundt said.
“The magnitudes that we get here in South Dakota really are not that high,” he said. “A lot of them are described as maybe dishes are rattling in the cabinet or pictures could be moving a little bit on wall or even the windows are shaking, much like the windows may shake during a thunderstorm or when we have a clap of thunder, if you are close enough to that lightning strike you can see that the windows are shaking a little bit.”
If you experience an earthquake during the winter months, you have a better chance of feeling the earthquake further away than where it actually occurred, he said, because it is easier for the shock to travel through the cold layers of earth or air at the time compared to the summer months.
The first recorded earthquake in South Dakota was in 1872, the United States Geological Survey says. Since then, there have been almost 100 documented earthquakes in the state. Most people affected by these earthquakes experience a low rumble in their homes, but no damage.
The United States Geological Survey has an interactive map, showing the earthquakes dating back to 1906. It shows their location, magnitude and date recorded.
The largest recorded earthquake in South Dakota was reported on June 2, 1911 south of Huron. It was a 4.5 magnitude quake.
The Centers for Disease Control and Prevention says that after an earthquake, you may experience aftershocks, which are smaller earthquakes that follow a larger earthquake. These aftershocks can happen minutes, days, weeks or even months after the initial earthquake.