Quakes shaking northeast Ohio | News, Sports, Jobs

With snow falling at one to two inches per hour early on Jan. 17, the banner winter storm was the main event on the minds of most Trumbull County residents — so it should come as no surprise another natural event that occurred that morning went all but unnoticed.

The Ohio Department of Natural Resources remote autonomous seismic network detected a 1.0 magnitude earthquake off Bell South Road near Wilson Sharpsville Road in Fowler. The quake happened around 3:15 a.m. at a depth of 5.1 miles.

The earthquake is one of 18 so far this year in Ohio — a “pretty high” number, according to Jeff Fox, a seismologist with the Ohio Department of Natural Resources. He said the ODNR typically detects two or three earthquakes per month.

“We haven’t really seen this many earthquakes in a short amount of time that I can remember,” Fox said.

The bulk of the earthquakes this year — 12 — have been logged just northwest of the Valley in Lake County, along a fault line of unknown length that runs 4 or 5 miles deep under Lake Erie, Fox said.

While it’s not exactly clear what’s been causing the activity in Lake County, Fox said it could be aftershock activity following a magnitude 4 earthquake in the summer of 2019 in that area.

He said aftershocks after this amount of time are “a bit unusual but not completely unheard of.”

Earthquakes happen along fault lines, usually when stress builds up. The force of friction holds the fault together until the stress becomes too great and the fault slides, causing an earthquake. The entire surface of the fault doesn’t necessarily slide at the same time because rock is elastic, meaning it can deform and recover its shape.

Fox said stress often transfers to other parts of the fault that are “locked” by irregularities such as bumps, stopping the rupture. When stress again overcomes friction, another earthquake will happen along the same fault.

He said that may be the case with the Lake County earthquakes, as they appear to be occurring east to west.

GEOLOGIC STRUCTURE

As for Fowler’s earthquake, Fox said it was unrelated “standard background tectonic activity” along a completely different fault.

“Northeast Ohio is very geologically complex,” he said.

He said Ohio’s “basement structure” — the oldest rocks buried completely under the surface — are the remains of ancient mountain ranges that have been eroded completely.

“Since they were thrust up and folded around back during that mountain building episode and buried, the natural stresses that are built up in the crust — there’s movement in them from time to time,” Fox said.

The glaciers that once covered Ohio also pressed down on the Earth’s crust, and now the crust is “rebounding,” Fox said.

Trumbull County’s last two earthquakes were in July and August 2014 — 1.7 and 2.1 magnitude quakes, both at about 1.9 miles deep and both with epicenters near Muno Park off North Main Street in Niles, according to ODNR data.

Mahoning County had six earthquakes in March 2014 — four of which happened March 10 at a depth of about 3.1 miles off Cowden Road in Lowellville, less than a mile from the Pennsylvania boarder. The other two earthquakes happened March 5 and 11 in the same area. All were between 2.1 and 3.0 magnitude.

“There’s all sorts of long-term weaknesses in the … deeper rocks in the Mahoning County area,” Jeffrey Dick, geology program coordinator at Youngstown State University, said.

MAGNITUDE

Dick, 65, grew up in southern California and lived in the Los Angeles area when the 6.6 magnitude Sylmar earthquake shook the area.

“I thought my mom was shaking me, waking me up to go to school — but it was my bed moving, like a poltergeist,” Dick said. “Those are the kinds of things that get your attention.”

Even having spent most of his life in Ohio, where earthquakes are rarely felt, Dick said remembers what “real earthquakes” feel like.

People usually don’t feel earthquakes below a 2.5 magnitude — though sometimes dogs notice them — and earthquakes below a 4.5 or 5 magnitude don’t cause noticeable damage.

For each whole number on the Richter scale, which measures earthquakes, the energy of the earthquake goes up tenfold, Dick explained. A 3.0 magnitude earthquake has the force of 10 2.0 quakes; a 4.0 has the force of 100 2.0s and a 5.0 has the force of 1,000 2.0s.

Ohio has had magnitude 5 earthquakes that have caused damage in the past, most recently in 1986 in — you guessed it — Lake County.

The largest recorded earthquake in the state was a quake that struck the town of Anna on March 9, 1937, according to Ohio History Connection. It was estimated to have a magnitude of 5.4 and reportedly caused damage to every chimney in Anna and cracked and separated walls in the school.

Earthquake magnitude is based on the rigidity of rocks, the size of the fault, and the distance the fault slips.

If seismologists can get a better idea of how big fault lines are, they can determine if those faults are capable of generating earthquakes with a magnitude of 5 or higher. Some research suggests Ohio could generate a magnitude 6 earthquake, Fox said.

“It’s a low probability, but the probability is not zero either,” Fox said.

Dick said he doesn’t think Ohio has the potential to produce a magnitude 6 earthquake because not enough stress is built up in the rocks — but large mid-continent earthquakes have happened and have caused damage.

From December 1811 to March 1812, a series of earthquakes hit New Madrid, Mo., with the largest estimated at an 8.8 magnitude, according to New Madrid’s website. Reports from that time indicate the earthquake reversed the flow of the Mississippi River for several hours, created a lake, destroyed a forest and drowned inhabitants of a Native American village.

TRACKING EARTHQUAKES

Since 2016, ODNR has been using a network of 26 remote, solar-powered seismometers that detect earthquakes and send the data back to seismologists in Delaware County in real time, Fox said.

One ODNR seismometer is located west of Youngstown Kingsville Road and north of Davis Peck Road in Gustavus, according to ODNR’s interactive earthquake epicenter map. Another is located near the southern tip of Salem Reservoir in Center Township in Columbiana County. The map shows Geauga and Lake counties also host ODNR seismometers.

Dick said YSU also has a seismometer that has been at the university for about 20 years. Plus, after a 2.7 and a 4.0 earthquake in Youngstown near Interstate 680 on Christmas Eve and New Year’s Eve 2011, the United States Geological Survey installed a sophisticated seismograph in the area, Dick said.

The information gathered by seismometers can be used to determine where faults are located and whether those faults are large enough to cause damaging earthquakes. In turn, that can help determine where to build earthquake-susceptible infrastructure such as homes, dams and power plants.

The series of small Lake County earthquakes has begun to delineate the outline of that fault line, Fox said.

“Earthquakes kind of help us orient which direction the fault aligns,” Fox said. “We pop them on the map as points, but they’re not really points, they’re linear, planar features.”

Fox said if you look at earthquakes like Lake County’s, “we can learn from them and they’re not big enough to do any damage — they’re good in that regard.”

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