The Columbus Dispatch
Recent NE Ohio earthquakes likely were aftershocks
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 firstname.lastname@example.org. Follow him @Jimmackinnonabj on Twitter or www.facebook.com/jimmackinnonabj.