Earthquakes / EVENT RECORD
M 4.5 - 158 km S of False Pass, Alaska
USGS · Every measurement below belongs to the selected record.
Read the source-series history ↗Around the epicentre
Regional view · markers are locations, not affected areas
Magnitude
M 4.5
Scale: mwr
Depth
20.471 km
from location
Reported by people
Not published
Number of felt reports
USGS review
reviewed
Review does not imply final measurements
What the record tells us
USGS reports a magnitude 4.5 earthquake in 158 km S of False Pass, Alaska, at a depth of 20.471 km.
Detailed source data captured 2026-10-21 15:40:15 UTC.
Measurements & confidence
- Event time (UTC)
- 2026-10-21 12:03:56.497 UTC
- Source updated (UTC)
- 2026-10-21 14:11:48.040 UTC
- Location
- 53.426°, -163.461°
- Stations used for location
- 94
- Horizontal error
- 5.92 km
- Depth error
- 5.649 km
- Magnitude error
- 0.071
Errors are the source’s reported uncertainty estimates, not guaranteed bounds. A depth marked “operator assigned” was fixed during analysis.
Shaking & impact
- Instrumental intensity
- Not published
- Felt-report intensity
- Not published
- PAGER impact alert
- Not published
No published assessment does not mean no shaking or no impact. A magnitude value alone cannot establish damage or a tsunami warning.
Nearby seismic activity
Within 500 km · M2.5+ · seven days before the event through the latest query, up to seven days after
10-14
0
10-15
4
10-16
8
10-17
1
10-18
4
10-19
3
10-20
1
10-21
0
Query window: 2026-10-14 12:03:56 to 2026-10-21 15:40:15 UTC. This is spatial proximity, not an identified aftershock sequence.
Magnitude
M 4.5
Scale: mwr
Depth
20.471 km
from location
Reported by people
Not published
Number of felt reports
USGS review
reviewed
Review does not imply final measurements
What the record tells us
USGS reports a magnitude 4.5 earthquake in 158 km S of False Pass, Alaska, at a depth of 20.471 km.
Detailed source data captured 2026-10-21 15:40:15 UTC.
Measurements & confidence
- Event time (UTC)
- 2026-10-21 12:03:56.497 UTC
- Source updated (UTC)
- 2026-10-21 14:11:48.040 UTC
- Location
- 53.426°, -163.461°
- Stations used for location
- 94
- Horizontal error
- 5.92 km
- Depth error
- 5.649 km
- Magnitude error
- 0.071
Errors are the source’s reported uncertainty estimates, not guaranteed bounds. A depth marked “operator assigned” was fixed during analysis.
Shaking & impact
- Instrumental intensity
- Not published
- Felt-report intensity
- Not published
- PAGER impact alert
- Not published
No published assessment does not mean no shaking or no impact. A magnitude value alone cannot establish damage or a tsunami warning.
Nearby seismic activity
Within 500 km · M2.5+ · seven days before the event through the latest query, up to seven days after
10-14
0
10-15
4
10-16
8
10-17
1
10-18
4
10-19
3
10-20
1
10-21
0
Query window: 2026-10-14 12:03:56 to 2026-10-21 15:40:15 UTC. This is spatial proximity, not an identified aftershock sequence.
The record as it develops
This timeline begins when our journal started capturing details. It is not a complete USGS revision history.
Captured 2026-10-21 14:25:14 UTC
First detailed capture · M4.5 · 20.471 km deep · 21 nearby records
Source updated 2026-10-21 14:11:48 UTC
Captured 2026-10-21 15:40:15 UTC
Updated capture · M4.5 · 20.471 km deep · 21 nearby records
Source updated 2026-10-21 14:11:48 UTC
Magnitude is not shaking
Magnitude describes the earthquake’s size. The shaking experienced at a place depends on distance, depth, local ground conditions and the rupture.
Depth needs context
A reported depth describes the location of the earthquake underground. Some solutions use an assigned depth; uncertainty and review status matter.
Nearby does not mean aftershock
Our regional search finds events by distance and time. Establishing an aftershock sequence requires seismological assessment.
This is a source-linked archive. Source measurements and assessments can change. An archived bulletin is not evidence that a warning is currently active.
In the daily journal
21 October 2026 ↗SOURCE ID usgs:us6000u3tn