WAUPACA COUNTY, Wis. (WBAY) - Over the weekend the United States Geological Survey confirmed reports of two earthquakes in Waupaca County this month.
The Waupaca County Emergency Management office received reports from residents last week of shaking buildings and rumbling noises in the area.
USGS said the first earthquake happened 7.5 miles north of Iola on July 7th just after 2:30 p.m. It was a magnitude 1.3, and then the second on July 15th was a 1.5. Other reported quakes have been too small to detect.
The last confirmed earthquake in Waupaca County was in March of 2012. As we reported, it was near Clintonville. The magnitude 1.5 quake made national headlines.
Action 2 News spoke to Gordy Barth, who said he was having a family cookout the first time it happened -- on July 7th this month.
“And then all of a sudden, the whole approach by the garage started shaking, the garage started shaking, my wife was in the house, she came running out, she thought something blew up downstairs,” said Barth.
Barth lives north of Iola. We asked USGS what could be causing this but it says right now they don't exactly know.
“Usually, when we have earthquakes in this part of the U.S, the earthquakes are a result of what we call isostatic rebound, because this area was covered with an ice sheet about 10,000 years ago, 12,000 years ago, it was a very thick ice sheet, it kind of pressed down on the continent, and once all that ice melted, the continent is gradually kind of springing back like a sponge,” said Paul Caruso a Geophysicist with USGS.
The USGS said it tracks earthquakes also because it helps with building codes, and knowing where those hazardous areas are, but it doesn’t consider Wisconsin to be hazardous.
Meanwhile, Barth said the tremors and sounds have not stopped for three weeks now.
"Like last night, all through the night, the way I describe it, if you're ice fishing and the ice chips or cracks underneath you, and you hear and then it just kind of echoes, that hollow sound, we hear that all night long."