Reviewed by USGSTonga6d ago
M4.5 earthquake 280 km WNW of Houma, Tonga
Sunday, September 20, 2026, 15:33:50 UTC · 20.373°S, 177.862°W
A magnitude 4.5 earthquake struck 280 km WNW of Houma, Tonga on Sunday, September 20, 2026, 15:33:50 UTC, at a depth of 513.3 km (deep). It is the strongest earthquake within 300 km since an M4.7 on September 18, 2026.
- Magnitude
- 4.5
- Light · mb
- Depth
- 513 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
85 tons of TNT
That is about 1/178 of the Hiroshima bomb. A magnitude 5.0 releases about 6 times more energy.
Tectonic setting
176 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
513 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 50 km
USGS has not published any M2.5+ earthquake within 50 km since this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 2,039 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.22018 Fiji EarthquakeAugust 19, 2018 · 253 km N of this epicenter
- 7.8159 km W of Pangai, TongaDecember 14, 1950 · 221 km E of this epicenter
- 7.8Fiji regionJanuary 1, 1919 · 119 km N of this epicenter
- 7.8192 km WSW of Haveluloto, TongaOctober 14, 1997 · 223 km SE of this epicenter
- 7.7Fiji regionAugust 19, 2002 · 226 km SW of this epicenter
- 7.6178 km E of Levuka, FijiFebruary 22, 1909 · 270 km NW of this epicenter
- 7.6240 km E of Levuka, FijiMarch 9, 1994 · 266 km N of this epicenter
- 7.5262 km WNW of Haveluloto, TongaMay 21, 1962 · 53 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 11 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 2018M8.2
Fiji Islands
19 Aug 2018 · 253 km away · intensity V
tsunami
- 1937M8.1
Fiji Islands
16 Apr 1937 · 154 km away
- 1909M7.8
Fiji Islands
22 Feb 1909 · 290 km away
- 1919M7.8
Fiji Islands
1 Jan 1919 · 119 km away
tsunami
- 1950M7.7
Tonga Islands
14 Dec 1950 · 218 km away · intensity VI
- 1997M7.7
Tonga Islands
14 Oct 1997 · 223 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.