Earthquakes in Minnesota?

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There was an earthquake in the Midwest today. The epicenter was in southern Illinois and apparently caused only minor damage.

The U.S. Geological Survey, keeper of the cool instruments that tell us the numbers, has a great idea: an online space where people can report how violent — or not — the earthquake was in their area. Unfortunately, at this point, it’s all about the numbers, and there’s no “community” space yet where people can share their stories, but the possibilities for quickly getting the information and then being able to plot it all on a map are enormous.

How common are earthquakes in Minnesota? Not very. The last one was February 9, 1994, a rip-roaring 3.1 centered in south-central Minnesota. In November 1968, another earthquake in south-central Illinois was strong enough to be felt in the Austin-to-Rochester area. The last strong earthquake in Minnesota was a 4.6 quake that cracked foundations in Stevens and Morris counties in 1975.

So I’m probably wasting my time asking you for stories of any time you felt an earthquake. I was in San Francisco last October for our 25th wedding anniversary. A fairly strong earthquake — at least by Minnesota standards — struck the San Jose area. We didn’t feel a thing although everyone on the street was talking about it. On the day after my first son was born, a 5.3 earthquake struck nearby Armonk, Minnesota New York (Westchester County). I felt that one, and took it as a sign.

  • http://www.trailblz.com Brian Hanf

    “On the day after my first son was born, a 5.3 earthquake struck nearby Armonk, Minnesota (Westchester County). I felt that one, and took it as a sign.”

    Sign of what?

  • GregS

    Good read on Minnesota geology and earthquakes here -> State of Minnesota Yellow Page Directory: Glaciers, Ecosystems, Earthquakes

    In the 141 years since 1860, Minnesota has recorded 18 earthquakes, more than half of them during the last 35 years. Most of Minnesota’s earthquakes occur along a line that runs from the southwest to the northeast through Ortonville, Morris, Alexandria, Staples and Nisswa. This area is part of the Great Lakes Tectonic Zone, which, along with the Yellow Medicine Shear Zone, was formed more than 2 billion years ago. They are called zones instead of faults because the exact location is hard to pin down, but runs in about a 30-mile wide band situated on the basis of earthquakes that have occurred in the past.

    The North American continent sits on a plate that is gradually moving westward, experiencing slippage on various fault lines and causing earthquakes. Faults are fractures in the rocks where pressure in the earth’s crust tends to be released. One theory says today’s Minnesota quakes are caused by glacial unloading. This is the rebounding of areas depressed by the weight of glaciers that buried Minnesota and much of the Dakotas about 12,000 years ago. The glaciers – over a mile thick – depressed the earth under their massive weight.

    Earthquakes measuring less than 5.0 on the Richter scale are generally considered minor quakes and cause little damage. About 6,200 minor quakes occur each year around the globe. Each increase in a whole number on the Richter scale represents a 10-fold increase in power and a 30-100 times increase in energy released. Damage usually occurs with magnitude 5-5.9 quakes. There are about 800 earthquakes around the world in that range every year. Only the few earthquakes that measure 6.5 and above have the ability to cause severe property damage and the loss of large numbers of lives. An earthquake registering between 7 and 8 on the Richter scale is classified as major, while anything higher than 8 qualifies as great.

    An earthquake, measuring about 4.7 on the Richter scale, occurred on July 10, 1975 in the neighboring towns of Alberta and Morris. No damages or injuries were reported. In June 1987, an earthquake registering 4.1 in Lawrenceville in southeastern Illinois was felt in southeastern Minnesota. The most recent quake felt in Minnesota occurred on October 20, 1995, centered next to the Minnesota border near Rosholt, S.D. The only recorded earthquake damage suffered in the state came in 1917 when a quake centered in Staples, registering 4.3 on the Richter scale, knocked down some chimneys. The most powerful quake in Minnesota was in 1860 and was estimated at 5.0. The Richter Scale was not invented until 1935. Below is a list of recorded quakes felt in Minnesota:

    Earthquakes in Minnesota: Date, Epicenter, County, Magnitude

    Date Epicenter County Magnitude

    1860 Long Prairie Todd 5.0

    Dec. 16, 1860 New Prague Scott 4.7

    Dec. 28, 1880 St. Vincent Kittson 3.6

    Feb. 6, 1917 Red Lake Beltrami 3.6

    Sept. 3, 1917 Staples Todd 4.3

    Dec. 23, 1923 Bowstring Itasca 3.8

    Jan. 28, 1939 Detroit Lakes Becker 3.9

    Feb. 15, 1950 Alexandria Douglas 3.6

    Sept. 28, 1964 Pipestone Pipestone 3.4

    July 9, 1975 Morris Stevens 4.7

    Mar. 6, 1979 Milaca Mille Lacs 1.0

    April 16, 1979 Evergreen Becker 3.1

    May 14, 1979 Rush City Chisago 1.0

    July 26, 1979 Nisswa Crow Wing 1.0

    April 24, 1981 Cottage Grove Washington 3.6

    Sept. 27, 1982 Walker Cass 2.0

    June 1987 Lawrenceville Lawrence, Ill. 4.1

    June 4, 1993 N.W. of Morris Stevens 4.1

    Feb. 9, 1994 N. of Granite Falls Yellow Medicine 3.1

    Oct. 20, 1995 Rosholt, Roberts, S.D. 3.7

    For more information, contact the Minnesota Geological Survey, 2642 University Ave., St. Paul, MN 55114-1057

  • Bob Collins

    That parenthood would be a bumpy ride. And guess what? (g)

  • http://wcco.com/jasonblog Jason DeRusha

    Bob: If your blog ever gets a ton of readers, I’m in trouble. This is the topic of my Good Question segment tonight.

    I was going to do another one on hockey pucks, but since that went over like a lead balloon…

  • Bob Collins

    Heh…

    I believe — and this is just a little news tip between me and you — that they are actually USING lead hockey pucks over at the X. But only when Gaborik touches it.

    Tons of readers? Gosh, I hope so, although I keep having this dream that I’ve been put in witness protection and they’re hiding me in the blogosphere.

  • Mac Wilson

    I went to school in Morris, and if you take their gen-ed geology course, you get a full, day-long rundown of the 1975 earthquake. The 1993 one was mentioned, too; I seem to recall that the geology discipline was holding its annual picnic at the exact time of the quake. In the words of our professor, “what are the odds?”

    My mother felt the 1994 earthquake in St. Cloud. She thought she was crazy until she heard it on the news later that night. An earthquake is something I’d like to experience someday, but only if I had the knowledge that everyone would be okay.

  • Carolyn

    I remember the one in 1975. I had been up a lot the night before with my two month old and I had just awoke from a nap. It was about 9:45 in the morning and I started shaking – thought what is the matter with you? Then it dawned on me that the cups hanging in the china closet in our trailer home were banging against each other also. I couldn’t figure out how I was making them shake! That night on the news I heard that we had had an earthquake and thought – ok – I’m not losing it and I really did feel something.

  • Tina

    this is some seriously interesting stuff–WOW! when I’ve told my kids that we’ve had earthquakes in Minnesota, they look at me like I’ve lost my cookies—-nope—all the cookies are accounted for-it’s true—–take that, youngins!!