5 km SW of Morenci, Arizona

2016-08-18 23:03 UTC · 0.0 km deep · released about 680 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: 2016-08-18 23:03 UTC
Magnitude: M 2.9 (ml)
Depth: 0.0 km below the surface
Felt: no reports yet
Nearest: Greenlee County, 26 km NNE
Status: Reviewed by a seismologist

USGS · last changed by USGS 3603 days ago · we first saw it 3603 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

USGS catalogues this as mining explosion, not an earthquake.

How big was it?

This earthquake released about 680 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

Mineral, Virginia 2011 M 5.8 22,000× the energy of this one
Magna, Utah 2020 M 5.7 16,000× the energy of this one
Around the size people start to feel M 3.0 1.4× the energy of this one
This earthquake M 2.9 about 680 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 33.0408, -109.4004. Map © OpenStreetMap contributors.

Nearby places

Place	Distance	Direction
Greenlee County, AZ	26 km (16 mi)	SW of here	earthquakes near Greenlee County
Graham County, AZ	46 km (29 mi)	ENE of here	earthquakes near Graham County
Grant County, NM	101 km (63 mi)	WNW of here	earthquakes near Grant County
Catron County, NM	134 km (83 mi)	SW of here	earthquakes near Catron County

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

Aftershocks so far

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

2.8 0 km NE of Clifton, Arizona 02:17 UTC
2.6 9 km N of San Jose, Arizona 23:25 UTC
3.3 3 km WSW of Franklin, Arizona 13:15 UTC
2.8 4 km SSW of Duncan, Arizona 11:59 UTC
2.7 3 km NNE of Franklin, Arizona 08:43 UTC
2.6 2 km NNE of Morenci, Arizona 22:21 UTC
2.7 6 km WSW of Franklin, Arizona 02:12 UTC
2.8 9 km SE of York, Arizona 03:39 UTC
2.2 24 km NNW of Morenci, Arizona 23:52 UTC
2.6 9 km WSW of Franklin, Arizona 12:25 UTC
3.0 10 km NNE of Safford, Arizona 23:50 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 07:27 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.