Reviewed by USGS22y ago
M4.3 earthquake in South Sandwich Islands region
Tuesday, September 14, 2004, 14:38:41 UTC · 55.275°S, 27.956°W
A magnitude 4.3 earthquake struck in South Sandwich Islands region on Tuesday, September 14, 2004, 14:38:41 UTC, at a depth of 10.0 km (shallow).
- Magnitude
- 4.3
- Light · mb
- Depth
- 10 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
43 tons of TNT
That is about 1/354 of the Hiroshima bomb. A magnitude 5.0 releases about 11 times more energy.
Tectonic setting
24 km
from the nearest mapped plate boundary, between the Sandwich and South American plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
10 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 5 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.5 on September 22, 2004. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.1South Sandwich Islands region22y ago · 21 km W of this epicenter
- 3.9South Sandwich Islands region22y ago · 24 km NW of this epicenter
- 4.2South Sandwich Islands region22y ago · 18 km NW of this epicenter
- 5.5South Sandwich Islands region22y ago · 35 km NW of this epicenter
- 4.5South Sandwich Islands region22y ago · 39 km NW of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 649 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.11929 South Sandwich Islands EarthquakeJune 27, 1929 · 89 km W of this epicenter
- 7.8South Sandwich Islands regionMay 26, 1964 · 118 km S of this epicenter
- 7.2South Sandwich Islands regionDecember 27, 1991 · 189 km SE of this epicenter
- 7.1South Sandwich Islands regionSeptember 8, 1961 · 124 km S of this epicenter
- 6.9South Sandwich Islands regionAugust 18, 1930 · 57 km S of this epicenter
- 6.9South Sandwich Islands regionSeptember 13, 1921 · 59 km SW of this epicenter
- 6.9South Sandwich Islands regionSeptember 6, 2004 · 65 km W of this epicenter
- 6.8South Sandwich Islands regionNovember 2, 1943 · 203 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 2 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1929M8.1
South Sandwich Islands
27 Jun 1929 · 89 km away
- 1961M7.7
South Sandwich Islands
8 Sep 1961 · 117 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.