Reviewed by USGS7y ago
M4.9 earthquake in South Sandwich Islands region
Sunday, December 30, 2018, 15:07:39 UTC · 56.652°S, 24.776°W
A magnitude 4.9 earthquake struck in South Sandwich Islands region on Sunday, December 30, 2018, 15:07:39 UTC, at a depth of 22.6 km (shallow). It is the strongest earthquake within 300 km since an M4.9 on December 27, 2018.
- Magnitude
- 4.9
- Light · mb
- Depth
- 23 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
338 tons of TNT
That is about 1/45 of the Hiroshima bomb. A magnitude 5.0 releases about 1 times more energy.
Tectonic setting
0 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
23 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 1,298 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.8South Sandwich Islands regionMay 26, 1964 · 180 km W of this epicenter
- 7.2South Sandwich Islands regionNovember 15, 1910 · 278 km S of this epicenter
- 7.2South Sandwich Islands regionDecember 27, 1991 · 75 km NW of this epicenter
- 7.2South Sandwich Islands regionMay 28, 2016 · 140 km W of this epicenter
- 7.1South Sandwich Islands regionSeptember 8, 1961 · 162 km W of this epicenter
- 7.1South Sandwich Islands regionDecember 11, 2018 · 231 km SW of this epicenter
- 7.0South Sandwich Islands regionJune 30, 2008 · 237 km SE of this epicenter
- 6.9South Sandwich Islands regionAugust 18, 1930 · 220 km NW 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:
- 1961M7.7
South Sandwich Islands
5 Sep 1961 · 201 km away
- 1961M7.7
South Sandwich Islands
8 Sep 1961 · 160 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.