QuakeScout
Magnitude4.0

Reviewed by USGSAlaska37y ago

M4.0 earthquake 137 km SE of Chignik, Alaska

Wednesday, September 6, 1989, 05:34:02 UTC · 55.464°N, 156.775°W

A magnitude 4.0 earthquake struck 137 km SE of Chignik, Alaska on Wednesday, September 6, 1989, 05:34:02 UTC, at a depth of 33.0 km (shallow).

Magnitude
4.0
Light · mb
Depth
33 km
Shallow
Felt reports
0
Did You Feel It?
Est. shaking
—
No ShakeMap
PAGER alert
None
Not issued
Tsunami
No flag
USGS feed

Outlined circle: this earthquake

In context

How big was it, and why here?

Energy released

15 tons of TNT

That is about 1/998 of the Hiroshima bomb. A magnitude 5.0 releases about 32 times more energy.

Tectonic setting

110 km

from the nearest mapped plate boundary, between the North American and Pacific plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: shallow

33 km

Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.

Did You Feel It?

Where it was felt

No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.

I felt it — report to USGS ↗

USGS PAGER estimate

Who was exposed to shaking

USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.

After the main event

Aftershocks within 50 km

USGS has not published any M2.5+ earthquake within 50 km in the 30 days after this event.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 201 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 8.21938 Semidi Islands, Alaska EarthquakeNovember 10, 1938 · 94 km W of this epicenter
  2. 7.454 km SE of Sand Point, AlaskaMay 31, 1917 · 204 km W of this epicenter
  3. 7.190 km SE of King Cove, AlaskaMay 14, 1948 · 296 km W of this epicenter
  4. 7.14 km ENE of Karluk, AlaskaNovember 7, 1912 · 278 km NE of this epicenter
  5. 7.0113 km ESE of Chignik, AlaskaMay 4, 1923 · 42 km N of this epicenter
  6. 7.0164 km SE of Chignik, AlaskaSeptember 4, 1989 · 27 km SE of this epicenter
  7. 6.9105 km ESE of Perryville, AlaskaNovember 17, 1938 · 61 km W of this epicenter
  8. 6.9143 km ESE of Chignik, AlaskaFebruary 13, 1951 · 49 km NE of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 11 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

  1. 1900M8.3

    Kodiak Island

    9 Oct 1900 · 272 km away · intensity VIII

    Limited damage (under $1M)

  2. 1788M8.0

    Unga Island

    21 Jul 1788 · 289 km away · intensity VII

    Limited damage (under $1M)tsunami

  3. 1970M6.0

    Andreanof Islands

    11 Mar 1970 · 287 km away · intensity V

    Limited damage (under $1M)tsunami

  4. 1938M8.2

    Alaska

    10 Nov 1938 · 101 km away · intensity VI

    tsunami

  5. 1788M8.0

    Alaska Peninsula

    6 Aug 1788 · 273 km away

    tsunami

  6. 1906M7.6

    Aleutian Islands

    23 Dec 1906 · 235 km away

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers

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