Reviewed by USGSAlaska18y ago
M2.8 earthquake 58 km E of Atka, Alaska
Friday, July 18, 2008, 14:49:32 UTC · 52.116°N, 173.353°W
A magnitude 2.8 earthquake struck 58 km E of Atka, Alaska on Friday, July 18, 2008, 14:49:32 UTC, at a depth of 49.6 km (shallow).
- Magnitude
- 2.8
- Minor · ml
- Depth
- 50 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
239 kg of TNT
That is about 1/63,000 of the Hiroshima bomb. A magnitude 5.0 releases about 1,995 times more energy.
Tectonic setting
125 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
50 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 M2.6 on August 16, 2008. 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 745 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 · 171 km SW of this epicenter
- 8.01986 Atka, Alaska EarthquakeMay 7, 1986 · 118 km SW of this epicenter
- 7.8234 km SSW of Nikolski, AlaskaMarch 7, 1929 · 281 km SE of this epicenter
- 7.65 km WNW of Adak, AlaskaFebruary 14, 1905 · 231 km W of this epicenter
- 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 233 km NE of this epicenter
- 7.346 km SSW of Adak, AlaskaJune 10, 1996 · 250 km W of this epicenter
- 7.175 km S of Adak, AlaskaMarch 14, 1957 · 255 km W of this epicenter
- 7.160 km SW of Adak, AlaskaMarch 12, 1957 · 277 km W 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, which together caused about 2 recorded deaths. The most severe:
- 1957M8.6
Alaska
9 Mar 1957 · 171 km away
2 deathsSevere damage ($5–24M)tsunami
- 1986M8.0
Aleutian Islands: Adak
7 May 1986 · 118 km away · intensity VI
Moderate damage ($1–5M)tsunami
- 1901M7.8
Aleutian Islands: Fox Islands
31 Dec 1901 · 177 km away
Limited damage (under $1M)tsunami
- 1996M7.9
Andreanof Islands
10 Jun 1996 · 300 km away · intensity VI
tsunami
- 1907M7.8
Aleutian Islands
2 Sep 1907 · 252 km away
- 1929M7.8
Aleutian Islands: Fox Islands
7 Mar 1929 · 263 km away · intensity V
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.