Reviewed by USGS3y ago
M4.4 earthquake western Indian-Antarctic Ridge
Friday, March 31, 2023, 22:57:38 UTC · 50.242°S, 114.766°E
A magnitude 4.4 earthquake struck western Indian-Antarctic Ridge on Friday, March 31, 2023, 22:57:38 UTC, at a depth of 10.0 km (shallow).
- Magnitude
- 4.4
- 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
60 tons of TNT
That is about 1/251 of the Hiroshima bomb. A magnitude 5.0 releases about 8 times more energy.
Tectonic setting
36 km
from the nearest mapped plate boundary, between the Australian and Antarctic 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 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M4.4 on April 1, 2023. 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 63 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 6.0southeast Indian RidgeJanuary 7, 1967 · 212 km NW of this epicenter
- 5.7western Indian-Antarctic RidgeMarch 5, 1988 · 225 km S of this epicenter
- 5.7western Indian-Antarctic RidgeNovember 10, 2016 · 35 km NW of this epicenter
- 5.7western Indian-Antarctic RidgeMay 5, 1988 · 61 km NE of this epicenter
- 5.6western Indian-Antarctic RidgeApril 27, 2010 · 9 km NW of this epicenter
- 5.6western Indian-Antarctic RidgeApril 11, 1977 · 228 km S of this epicenter
- 5.6western Indian-Antarctic RidgeMarch 31, 2023 · 57 km NW of this epicenter
- 5.6western Indian-Antarctic RidgeAugust 30, 2012 · 50 km W of this epicenter