Reviewed by USGS22y ago
M4.7 earthquake in South Sandwich Islands region
Thursday, November 18, 2004, 03:22:57 UTC · 55.164°S, 29.058°W
A magnitude 4.7 earthquake struck in South Sandwich Islands region on Thursday, November 18, 2004, 03:22:57 UTC, at a depth of 44.0 km (shallow). It is the strongest earthquake within 300 km since an M5.8 on November 7, 2004.
- Magnitude
- 4.7
- Light · mb
- Depth
- 44 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 earthquake
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
16 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
44 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 has not published any M2.5+ earthquake within 50 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 592 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 · 30 km SW of this epicenter
- 7.8South Sandwich Islands regionMay 26, 1964 · 156 km SE of this epicenter
- 7.2South Sandwich Islands regionDecember 27, 1991 · 257 km SE of this epicenter
- 7.1South Sandwich Islands regionSeptember 8, 1961 · 168 km SE of this epicenter
- 6.9South Sandwich Islands regionAugust 18, 1930 · 97 km SE of this epicenter
- 6.9South Sandwich Islands regionSeptember 13, 1921 · 57 km SE of this epicenter
- 6.9South Sandwich Islands regionSeptember 6, 2004 · 24 km S of this epicenter
- 6.8South Sandwich Islands regionNovember 2, 1943 · 258 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 · 30 km away
- 1961M7.7
South Sandwich Islands
8 Sep 1961 · 165 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.