Reviewed by USGS11y ago
M5.0 earthquake in South Sandwich Islands region
Wednesday, September 9, 2015, 12:01:47 UTC · 56.182°S, 27.580°W
A magnitude 5.0 earthquake struck in South Sandwich Islands region on Wednesday, September 9, 2015, 12:01:47 UTC, at a depth of 104.6 km (intermediate). It is the strongest earthquake within 300 km since an M5.8 on August 26, 2015.
- Magnitude
- 5.0
- Moderate · mb
- Depth
- 105 km
- Intermediate
- Felt reports
- 0
- Max intensity I
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
477 tons of TNT
That is about 1/32 of the Hiroshima bomb. Each whole step in magnitude is about 32 times more energy.
Tectonic setting
109 km
from the nearest mapped plate boundary, between the Sandwich and South American plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: intermediate
105 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
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 75 km
USGS lists 9 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.7 on September 30, 2015. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.4South Sandwich Islands region11y ago · 8 km E of this epicenter
- 5.7South Sandwich Islands region11y ago · 9 km W of this epicenter
- 4.4South Sandwich Islands region11y ago · 22 km SE of this epicenter
- 4.7South Sandwich Islands region11y ago · 69 km NE of this epicenter
- 4.6South Sandwich Islands region11y ago · 26 km NW of this epicenter
- 4.3South Sandwich Islands region11y ago · 49 km E of this epicenter
- 4.6South Sandwich Islands region11y ago · 8 km N of this epicenter
- 4.7South Sandwich Islands region11y ago · 32 km E of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 1,057 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 · 142 km NW of this epicenter
- 7.8South Sandwich Islands regionMay 26, 1964 · 16 km S of this epicenter
- 7.2South Sandwich Islands regionDecember 27, 1991 · 144 km E of this epicenter
- 7.1South Sandwich Islands regionSeptember 8, 1961 · 22 km SE of this epicenter
- 6.9South Sandwich Islands regionAugust 18, 1930 · 50 km NW of this epicenter
- 6.9South Sandwich Islands regionSeptember 13, 1921 · 92 km NW of this epicenter
- 6.9South Sandwich Islands regionSeptember 6, 2004 · 125 km NW of this epicenter
- 6.9South Sandwich Islands regionJune 29, 2014 · 93 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 3 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 · 142 km away
- 1961M7.7
South Sandwich Islands
5 Sep 1961 · 205 km away
- 1961M7.7
South Sandwich Islands
8 Sep 1961 · 20 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.