Where 7 Pa. earthquakes this year have occurred

A 3.4 magnitude earthquake struck around 8:30 p.m. Wednesday in Juniata County, according to the U.S. Geological Survey. A short time later, a small aftershock hit the same area, bringing the total number of earthquakes to hit Pennsylvania this year to seven.

The 3.4 quake was the strongest so far, USGS data shows.

The aftershock was measured at 1.4 magnitude, the USGS website says.

Here are the seven earthquakes:

Feb. 26: 1.1 magnitude in the area of Shippensburg (Cumberland and Franklin counties)

March 18: 1.1 magnitude in the area of Whitfield (Berks County)

April 10: 1.6 magnitude in the area of Whitfield (Berks County)

April 11: 1.0 magnitude in the area of Wernersville (Berks County)

April 20: 0.9 magnitude in the area of Wernersville (Berks County)

June 13: 3.4 magnitude in the area of Mifflintown (Juniata County)

June 13, 2019: 1.4 magnitude in the area of Mifflintown (Juniata County)

The strongest quake to hit Pennsylvania is up for dispute. Originally, a 5.2 magnitude quake caused minor damage in the Greenville-Jamestown area in the northwest part of the state on Sept. 25, 1998. The USGS, however, has the quake officially recorded at 4.5 magnitude.

The last noticeable event felt in the Lehigh Valley was a 5.8 magnitude earthquake centered in Virginia in August 2011. It could be felt as far west as Detroit and Chicago, to the south in Georgia and as far north as Maine.

A public Hazard Mitigation Plan from the Northampton County Emergency Management agency says about 35 earthquakes have caused light damage in Pennsylvania since the Colonial period. Nearly half of these events had out-ofstate epicenters.

The USGS says earthquakes less than 2.5 magnitude are usually not felt but can be recorded by a seismograph, which measures the force and duration of a quake. A quake with a magnitude between 2.5 to 5.4 is often felt but causes only minor damage.