Reviewed by USGSAlaska40y ago
M4.7 earthquake 43 km W of Atka, Alaska
Sunday, June 29, 1986, 04:32:10 UTC · 52.255°N, 174.836°W
A magnitude 4.7 earthquake struck 43 km W of Atka, Alaska on Sunday, June 29, 1986, 04:32:10 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M5.4 on June 29, 1986.
- Magnitude
- 4.7
- 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 earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
169 tons of TNT
That is about 1/89 of the Hiroshima bomb. A magnitude 5.0 releases about 3 times more energy.
Tectonic setting
155 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 lists 2 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.6 on July 20, 1986. 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 474 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.61957 Atka, Alaska EarthquakeMarch 9, 1957 · 100 km SW of this epicenter
- 8.01986 Atka, Alaska EarthquakeMay 7, 1986 · 82 km S of this epicenter
- 7.65 km WNW of Adak, AlaskaFebruary 14, 1905 · 134 km W of this epicenter
- 7.388 km WSW of Adak, AlaskaJuly 7, 1929 · 218 km W of this epicenter
- 7.2162 km WSW of Adak, AlaskaMarch 16, 1957 · 292 km W of this epicenter
- 7.175 km S of Adak, AlaskaMarch 14, 1957 · 176 km SW of this epicenter
- 7.160 km SW of Adak, AlaskaMarch 12, 1957 · 186 km SW of this epicenter
- 7.158 km WNW of Atka, AlaskaFebruary 28, 1970 · 26 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 6 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 2 recorded deaths. The most severe:
- 1957M8.6
Alaska
9 Mar 1957 · 100 km away
2 deathsSevere damage ($5–24M)tsunami
- 1986M8.0
Aleutian Islands: Adak
7 May 1986 · 82 km away · intensity VI
Moderate damage ($1–5M)tsunami
- 1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 277 km away
Limited damage (under $1M)tsunami
- 1971M7.1
Andreanof Islands
2 May 1971 · 188 km away · intensity VI
tsunami
- 1986M6.4
Andreanof Islands
17 May 1986 · 24 km away
tsunami
- 1946
East Aleutian Islands
1 Nov 1946 · 87 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.