Earthquake · reviewed by a seismologist
M 1.8ml
Earthquake near Boulder City, NV
No earthquake was likely felt in Boulder City in the 24 hours to 7:47 pm PST (03:47 UTC). The last one was M 1.9, 6 km (4 mi) N, at 2:24 pm PDT on 3 July 2026, estimated intensity II (weak) in town. Every earthquake near Boulder City
This page: a magnitude 1.8 earthquake was recorded 3 km (2 mi) south of Boulder City, NV, at 8:04 pm PDT on 18 September 2021 (03:04 UTC), 10 km deep. 26 people have reported feeling it to USGS.
USGS: 3 km S of Boulder City, Nevada
19 km (12 mi) ESE of Henderson, NV
- When
- 8:04 pm PDT on 18 September 2021 ()
- Where
- 3 km (2 mi) south of Boulder City, NV · earthquakes near Boulder City
- Magnitude
- M 1.8 (ml)
- Depth
- 10 km below the surface
- Felt
- 26 reports · strongest reported intensity III
- Nearest
- Clark County, 34 km NNW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1806 days ago
Earthquake alerts for Boulder City, NV
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
At this magnitude and depth, people at rest would likely notice it out to about 9 km (6 mi) from the epicentre. In Boulder City, 3 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.
Earthquakes near other towns within 30 km: Henderson, Whitney.
How big was it?
This earthquake released about 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
- Magna, Utah 2020 M 5.7 710,000× the energy of this one
- Around the size people start to feel M 3.0 63× the energy of this one
- This earthquake M 1.8 about 15 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.
For this area
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.0 1 km SE of Boulder City, Nevada · 2 km NNE of this epicentre
Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.
Where
Epicentre 35.9484, -114.8270. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Clark County, NV | 34 km (21 mi) | NNW | earthquakes near Clark County |
| Mohave County, AZ | 100 km (62 mi) | ESE | earthquakes near Mohave County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
48 earthquakes have been recorded within 50 km since this one.
- 1.6 10 km SW of Enterprise, Nevada
- 1.6 9 km NE of Whitney, Nevada
- 1.5 1 km WNW of Spring Valley, Nevada
- 1.6 10 km SSE of Enterprise, Nevada
- 1.7 9 km ENE of Whitney, Nevada
- 1.6 8 km SSE of Paradise, Nevada
- 1.7 9 km WSW of Henderson, Nevada
- 1.6 8 km SSW of Henderson, Nevada
- 2.0 4 km SW of Enterprise, Nevada
- 1.8 18 km E of Nellis Air Force Base, Nevada
- 2.1 14 km SSE of Enterprise, Nevada
- 2.4 11 km ESE of Enterprise, Nevada
- 1.8 8 km SSW of Whitney, Nevada
- 2.3 3 km SSW of Enterprise, Nevada
- 1.9 8 km SE of Enterprise, Nevada
Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . 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.