37 km SSE of Kaibab, Arizona

2021-09-21 12:56 UTC · 18 km deep · released about 480 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: 2021-09-21 12:56 UTC
Magnitude: M 2.8 (ml)
Depth: 18 km below the surface
Felt: 2 reports · strongest reported intensity II
Nearest: Kane County, 99 km NE
Status: Reviewed by a seismologist

USGS · last changed by USGS 1759 days ago · we first saw it 1759 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 2 people have reported feeling it to USGS.

How big was it?

This earthquake released about 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
Magna, Utah 2020 M 5.7 22,000× the energy of this one
Around the size people start to feel M 3.0 2× the energy of this one
This earthquake M 2.8 about 480 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 36.5980, -112.5358. Map © OpenStreetMap contributors.

Nearby places

Place	Distance	Direction
Kane County, UT	99 km (61 mi)	SW of here	earthquakes near Kane County
Coconino County, AZ	109 km (68 mi)	NW of here	earthquakes near Coconino County
Washington County, UT	112 km (70 mi)	SE of here	earthquakes near Washington County
Mohave County, AZ	146 km (91 mi)	NE of here	earthquakes near Mohave County

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

Aftershocks so far

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

1.9 18 km E of Fredonia, Arizona 12:48 UTC
1.5 17 km S of Cane Beds, Arizona 21:35 UTC
1.8 7 km SE of Fredonia, Arizona 16:43 UTC
1.7 11 km ESE of Fredonia, Arizona 14:51 UTC
1.8 3 km ENE of Cane Beds, Arizona 16:56 UTC
1.7 15 km SSW of Cane Beds, Arizona 05:06 UTC
1.7 7 km E of Fredonia, Arizona 23:00 UTC
1.8 12 km ESE of Fredonia, Arizona 22:21 UTC
2.0 12 km ESE of Fredonia, Arizona 15:50 UTC
1.8 12 km ESE of Fredonia, Arizona 02:28 UTC
1.9 11 km ESE of Fredonia, Arizona 05:50 UTC
1.6 11 km SE of Fredonia, Arizona 16:19 UTC
1.9 11 km SE of Fredonia, Arizona 17:49 UTC
1.8 16 km S of Centennial Park, Arizona 17:15 UTC
2.0 11 km SE of Fredonia, Arizona 08:05 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 19:05 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.