Updated 2026-04-15 18:42:11 UTC

M 8.2 — 2021 Chignik, Alaska Earthquake

Magnitude 8.2, depth 35.0 km, 2021-07-29 06:15:49 UTC.

MagnitudeM 8.2
Depth35.0 km
Felt reports512
Statusreviewed
TsunamiYes

Alaska →

Quake Pulse

What to know

A short factual reading of this event from the available observations.

  • Magnitude M 8.2 at 35.0 km depth.
  • 512 felt report(s) are associated with the USGS record.
  • The USGS tsunami flag is enabled for this event.
  • The available PAGER level is YELLOW.
Counts describe detected earthquakes and are not a forecast or hazard assessment.
Quake Pulse

Within the Quake Pulse database

Long-term comparisons are more robust at higher magnitudes because small-earthquake detection capability has changed over time.

Magnitude rank in database#12
M4.5+ within 250 km, ±15 days27
Sequence context28 events →
Remarkable

Why this event stands out

high magnitude · tsunami flag · PAGER level · high USGS significance

94/100
Quake Pulse

Impact and context

Descriptive indicators available for this event and its surroundings.

90/100Very high context
Felt reports512
Max felt intensity (CDI)9.1
Instrumental intensity (MMI)7.4
PAGER alertYELLOW
Tsunami indicatorYES
USGS significance1,500
Depth contextShallow
Nearby major city—
● Quake Pulse Alerts

Follow this area

Get an e-mail when a new earthquake matches your threshold.

Create an alert →

These indicators describe data available after detection. They are neither a forecast nor a direct estimate of damage or individual risk.

Quake Pulse

Around this epicenter

Nearby events observed around this epicenter. Spatial proximity does not necessarily mean they belong to the same sequence.

Descriptive map centered on the epicenter; it does not represent felt intensity or risk.

Sequence context

This event belongs to a sequence detected by Quake Pulse.

Open sequence →

Nearby events · 100 km

Quake Pulse

USGS data evolution

Earthquake parameters can be revised after first publication. This timeline shows versions retained by Quake Pulse.

Revisions1
Magnitude change+0.0M 8.2 → M 8.2
Depth change+0.0 km
Last update255173 min
2026-04-15 18:42:11 UTC2026-04-15 18:42:11 UTC

Explore related context

Putting this earthquake in context

An earthquake record can change after the first automatic publication as additional stations contribute data and analysts refine the solution.

Interpret the numbers

Magnitude, depth, felt reports and status describe different parts of the event. None of them alone predicts the consequences for a specific city.

Important limits

If the earthquake creates a safety concern, follow local authorities and official warning channels rather than relying on a public data website.

Read the methodology →

Blog

Latest from the blog

Guides, explainers and practical reading to go beyond the live data.

View all articles →