A 2.1 magnitude earthquake occurred in Washington County at 2:58 a.m. Tuesday, according to the Pennsylvania State Seismic Network, which measures and lists all earthquakes in the state.
The shallow quake occurred 6.2 miles south of the city of Washington in a rural area, at a depth of about 1.8 miles.
Earthquakes with a magnitude of 2.5 or less are usually not felt at the surface. The epicenter of the quake was 1,000 feet southeast of the intersection of state Route 221, also known as South Bridge Road, and Verner Lane.
Earthquake magnitudes measure the size, or amplitude, of seismic waves generated by earthquakes and recorded by seismographs.
It’s possible for a 2.1 magnitude earthquake to be felt near its epicenter, but it would not be expected to cause property damage.
Before Tuesday, the most recent seismic event in Pennsylvania with a magnitude above 2 occurred on Sept. 15, when a 2.7 magnitude earthquake was measured just west of York, according to the Seismic Network Webpage.
An estimated 500,000 detectable earthquakes occur in the world each year, but only 100,000 of those are strong enough to be felt and just 100 cause significant damage in populated areas.
In addition to the small quake in Washington County, Tuesday, a 2.6 magnitude quake occurred along Lake Erie, east of Cleveland and just south of Madison, Ohio. And a 4.5 magnitude earthquake occurred in the San Francisco Bay area.
First Published: October 15, 2019, 8:01 p.m.