Reviewed by USGSAlaska12y ago
M3.5 earthquake in Rat Islands, Aleutian Islands, Alaska
Monday, July 21, 2014, 23:23:13 UTC · 52.004°N, 177.400°E
A magnitude 3.5 earthquake struck in Rat Islands, Aleutian Islands, Alaska on Monday, July 21, 2014, 23:23:13 UTC, at a depth of 3.2 km (shallow).
- Magnitude
- 3.5
- Minor · ml
- Depth
- 3 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
3 tons of TNT
That is about 1/5,615 of the Hiroshima bomb. A magnitude 5.0 releases about 178 times more energy.
Tectonic setting
131 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
3 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 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M2.7 on August 9, 2014. 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 797 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.71965 Western Aleutian Islands (Hawadax/Rat Islands) EarthquakeFebruary 4, 1965 · 123 km SE of this epicenter
- 8.31906 Western Aleutian Islands (Hawadax/Rat Islands) EarthquakeAugust 17, 1906 · 56 km E of this epicenter
- 7.9Rat Islands, Aleutian Islands, AlaskaJune 23, 2014 · 93 km E of this epicenter
- 7.8Rat Islands, Aleutian Islands, AlaskaNovember 17, 2003 · 129 km SE of this epicenter
- 7.6Rat Islands, Aleutian Islands, AlaskaMarch 30, 1965 · 194 km S of this epicenter
- 7.636 km NE of Attu Station, AlaskaFebruary 2, 1975 · 291 km NW of this epicenter
- 7.4265 km WSW of Adak, AlaskaFebruary 4, 1965 · 164 km E of this epicenter
- 7.2238 km SSE of Attu Station, AlaskaSeptember 8, 1939 · 203 km SW 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:
- 1975M7.6
Aleutian Islands: Near Islands
2 Feb 1975 · 291 km away · intensity IX
Moderate damage ($1–5M)
- 1965M8.7
Aleutian Islands: Rat Islands
4 Feb 1965 · 123 km away · intensity VI
Under $1 million damagetsunami
- 1906M8.3
Aleutian Islands: Rat Islands
17 Aug 1906 · 56 km away
- 2014M7.9
Aleutian Islands
23 Jun 2014 · 93 km away · intensity VI
tsunami
- 1909M7.8
Aleutian Islands
10 Apr 1909 · 164 km away
- 2003M7.8
Aleutian Islands: Rat Islands
17 Nov 2003 · 129 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.