3 km WNW of Willow Street, Pennsylvania

2017-04-23 20:49 UTC · 5.0 km deep · released about 85 lb of TNT

Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.

When: 2017-04-23 20:49 UTC
Magnitude: M 2.3 (ml)
Depth: 5.0 km below the surface
Felt: 1343 reports · strongest reported intensity V
Nearest: Lancaster County, 8 km NE
Status: Reviewed by a seismologist

USGS · last changed by USGS 905 days ago · we first saw it 905 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 1343 people have reported feeling it to USGS.

How big was it?

This earthquake released about 85 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

Mineral, Virginia 2011 M 5.8 180,000× the energy of this one
Magna, Utah 2020 M 5.7 130,000× the energy of this one
Around the size people start to feel M 3.0 11× the energy of this one
This earthquake M 2.3 about 85 lb of TNT

Energy from the Gutenberg–Richter relation (log₁₀E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

Where

Map loads when it scrolls into view

Epicentre 39.9930, -76.3127. Map © OpenStreetMap contributors.

Nearby places

Place	Distance	Direction
Lancaster County, PA	8 km (5 mi)	SW of here	earthquakes near Lancaster County
York County, PA	36 km (23 mi)	ENE of here	earthquakes near York County
Lebanon County, PA	44 km (27 mi)	SSE of here	earthquakes near Lebanon County
Chester County, PA	48 km (30 mi)	W of here	earthquakes near Chester County
Harford County, MD	51 km (31 mi)	N of here	earthquakes near Harford County
Berks County, PA	57 km (36 mi)	SW of here	earthquakes near Berks County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

12 earthquakes have been recorded within 50 km since this one.

1.7 3 km S of Rising Sun, Maryland 09:54 UTC
2.1 2 km W of Rising Sun, Maryland 04:41 UTC
2.4 8 km NE of Bel Air North, Maryland 15:02 UTC
1.9 0 km W of Shillington, Pennsylvania 20:36 UTC
2.1 2 km WSW of Sinking Spring, Pennsylvania 03:47 UTC
1.5 6 km N of Wernersville, Pennsylvania 07:06 UTC
1.7 2 km W of Sinking Spring, Pennsylvania 18:40 UTC
2.2 4 km NW of Spring Ridge, Pennsylvania 17:11 UTC
1.6 5 km NNE of Wernersville, Pennsylvania 17:46 UTC
1.7 1 km NNW of Spring Ridge, Pennsylvania 09:48 UTC
1.9 0 km N of Colony Park, Pennsylvania 07:49 UTC
1.8 4 km NNE of Susquehanna Trails, Pennsylvania 05:26 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 10:15 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

The official USGS event page — the source of record for every value above
Did you feel it? Report it to USGS — reports go to USGS, not to us
ShakeMap for this event, when USGS has produced one

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.