Reviewed by USGSTonga118y ago
M7.0 earthquake 254 km WNW of Houma, Tonga
Wednesday, April 20, 1910, 22:22:02 UTC · 20.251°S, 177.544°W
A magnitude 7.0 earthquake struck 254 km WNW of Houma, Tonga on Wednesday, April 20, 1910, 22:22:02 UTC, at a depth of 350.0 km (deep). It is the strongest earthquake within 300 km since an M7.6 on February 22, 1909.
- Magnitude
- 7.0
- Major · mB
- Depth
- 350 km
- Deep
- 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
477 kilotons of TNT
That is about 32 times the Hiroshima bomb. It released about 1,000 times the energy of a magnitude 5.0.
Tectonic setting
143 km
from the nearest mapped plate boundary, between the Tonga and Australian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: deep
350 km
Deep earthquakes (over 300 km) happen deep inside subducting plates. They rarely cause damage, but can be felt faintly over very large distances.
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 200 km
USGS has not published any M2.5+ earthquake within 200 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 4 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 4 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1903M8.0
Tonga Islands
4 Jan 1903 · 267 km away
- 1909M7.8
Fiji Islands
22 Feb 1909 · 293 km away
- 1853
Tonga Trench
24 Dec 1853 · 267 km away
tsunami
- 1907
S Of Tonga
1907 · 215 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.