The Columbus Dispatch

Recent NE Ohio earthquake­s likely were aftershock­s

- Jim Mackinnon Akron Beacon Journal USA TODAY NETWORK

Northeast Ohio earthquake­s that slightly shook, rattled and rolled Lake County and next door in Ashtabula this past week were nothing unusual for the area, a state seismologi­st says.

“It’s kind of normal earthquake activity for that region of Ohio,” said Jeff Fox, seismologi­st with the Ohio Department of Natural Resources. “It’s one of our more seismicall­y active regions in the state.”

The state placed earthquake detection equipment on Lake Erie bluffs in Lake County because of the history of earthquake­s in the area, he said. Plans are to upgrade the equipment sometime this summer, including putting sensors deep in the ground that can detect microquake­s, to give seismologi­sts a better idea of what is doing on there, Fox said.

The Lake County site is one of 21 monitoring stations, called the Ohio Seismic Network, that are scattered around Ohio and continuous­ly monitor for earthquake activity.

The underlying structure of the geology in the Lake County area makes it prone to earthquake­s, Fox said. This week’s earthquake­s took place about 3 kilometers below the surface of the earth, which makes them relatively shallow quakes, he said.

“There’s a lot of faults in that region of the state,” Fox said. “Another aspect, too, is we have more monitoring up there so we’re picking up more earthquake­s.”

A magnitude 3 earthquake hit at 8:20 a.m. Tuesday under Lake Erie near Timberlake in Lake County. On Wednesday, a second quake, magnitude 2, took place 5:25 a.m. in the immediate area.

“There was actually a third earthquake in Ashtabula County ... but it was small enough [magnitude 1.5] that it didn’t really attract any attention,” Fox said. That quake was detected at 3:21 a.m. Thursday.

The earthquake­s were small enough that most sleeping people would never have noticed, Fox said.

“People don’t tend to start feeling them until they are about 2.5 magnitude,” Fox said.

This week’s Lake County earthquake­s were close in location to a magnitude 4 earthquake that took place in 2019 and likely were aftershock­s of that larger earthquake, Fox said.

“It’s probably still some residual aftershock activity in that fault,” he said. “We’ve picked up some activity here and there over the past two years in the same region . ... This is just normal earthquake activity.”

In 1986, the area was hit with a magnitude 5 earthquake, and there was another large earthquake in 1946, Fox noted. “It’s not unheard of,” he said.

The ODNR website has an interactiv­e map showing the location, history and other informatio­n of earthquake­s in the state.

Besides the improved equipment going into Lake County later this year, Fox’s department also hopes to put sensors elsewhere in the region that will help seismologi­sts better triangulat­e earthquake­s.

“We like to surround earthquake faults with sensors,” Fox said. Sensors for now will not be placed under Lake Erie because of the expense and difficulty involved, he said.

The state earthquake website has a “Did your feel it?” area where people can go and fill in where they live and what they felt, Fox said. That informatio­n helps seismologi­sts better understand earthquake­s, he said. “It is kind of normal activity. It probably stems from the larger event in 2019, and we are continuing to monitor it,” Fox said.

Beacon Journal reporter Jim Mackinnon can be reached at 330-996-3544 or jmackinnon@thebeaconj­ournal.com. Follow him @Jimmackinn­onabj on Twitter or www.facebook.com/jimmackinn­onabj.

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