Reviewed by USGSAlaska37y ago
M7.0 earthquake 164 km SE of Chignik, Alaska
Monday, September 4, 1989, 13:14:58 UTC · 55.322°N, 156.429°W
A magnitude 7.0 earthquake struck 164 km SE of Chignik, Alaska on Monday, September 4, 1989, 13:14:58 UTC, at a depth of 11.0 km (shallow). It is the strongest earthquake within 300 km since an M8.2 on November 10, 1938.
- Magnitude
- 7.0
- Major · mw
- Depth
- 11 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 earthquakeDashed circle: 200 km aftershock search area
In context
How big was it, and why here?
Energy released
477 kilotons of TNT
That is about 32 times the Hiroshima bomb. It released about 1,000 times the energy of a magnitude 5.0.
Tectonic setting
87 km
from the nearest mapped plate boundary, between the North American and Pacific plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
11 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 200 km
USGS lists 3 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M4.0 on September 6, 1989. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 208 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.21938 Semidi Islands, Alaska EarthquakeNovember 10, 1938 · 112 km W of this epicenter
- 7.454 km SE of Sand Point, AlaskaMay 31, 1917 · 222 km W of this epicenter
- 7.14 km ENE of Karluk, AlaskaNovember 7, 1912 · 282 km NE of this epicenter
- 7.0113 km ESE of Chignik, AlaskaMay 4, 1923 · 62 km N of this epicenter
- 6.9105 km ESE of Perryville, AlaskaNovember 17, 1938 · 83 km W of this epicenter
- 6.9143 km ESE of Chignik, AlaskaFebruary 13, 1951 · 54 km N of this epicenter
- 6.9171 km SW of Akhiok, AlaskaFebruary 6, 1964 · 58 km NE of this epicenter
- 6.8100 km SSE of Old Harbor, AlaskaJune 19, 1986 · 247 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 10 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1900M8.3
Kodiak Island
9 Oct 1900 · 268 km away · intensity VIII
Limited damage (under $1M)
- 1788M8.0
Unga Island
21 Jul 1788 · 283 km away · intensity VII
Limited damage (under $1M)tsunami
- 1970M6.0
Andreanof Islands
11 Mar 1970 · 288 km away · intensity V
Limited damage (under $1M)tsunami
- 1938M8.2
Alaska
10 Nov 1938 · 124 km away · intensity VI
tsunami
- 1788M8.0
Alaska Peninsula
6 Aug 1788 · 292 km away
tsunami
- 1906M7.6
Aleutian Islands
23 Dec 1906 · 231 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.