Reviewed by USGSTonga9d ago
M5.3 earthquake 155 km SSE of Hihifo, Tonga
Thursday, September 17, 2026, 04:06:53 UTC · 17.323°S, 173.448°W
A magnitude 5.3 earthquake struck 155 km SSE of Hihifo, Tonga on Thursday, September 17, 2026, 04:06:53 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M5.3 on September 8, 2026.
- Magnitude
- 5.3
- Moderate · 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 earthquake
In context
How big was it, and why here?
Energy released
1 kilotons of TNT
That is about 1/11 of the Hiroshima bomb. It released about 3 times the energy of a magnitude 5.0.
Tectonic setting
112 km
from the nearest mapped plate boundary, between the Tonga and Pacific plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
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 75 km
USGS has not published any M2.5+ earthquake within 75 km since this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 2,438 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.11919 Tonga EarthquakeApril 30, 1919 · 154 km SE of this epicenter
- 8.12009 Samoa EarthquakeSeptember 29, 2009 · 250 km NE of this epicenter
- 8.0The 1917 Samoa-Tonga EarthquakeJune 26, 1917 · 259 km N of this epicenter
- 7.8146 km ESE of Hihifo, TongaDecember 26, 1975 · 157 km NE of this epicenter
- 7.7133 km NE of Hihifo, TongaSeptember 1, 1981 · 266 km N of this epicenter
- 7.682 km WNW of Hihifo, TongaMay 10, 2023 · 219 km NW of this epicenter
- 7.6199 km ESE of Hihifo, TongaApril 2, 1977 · 160 km NE of this epicenter
- 7.5158 km W of Neiafu, TongaMarch 24, 2026 · 254 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 16 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 194 recorded deaths. The most severe:
- 2009M8.1
Samoa Islands
29 Sep 2009 · 250 km away
192 deaths$285 million damagetsunami
- 1917M8.3
Samoa Islands
26 Jun 1917 · 208 km away
2 deathsModerate damage ($1–5M)tsunami
- 1919M8.1
Tonga Islands
30 Apr 1919 · 151 km away
Limited damage (under $1M)tsunami
- 1865M8.0
Tonga Islands
18 Nov 1865 · 242 km away
Limited damage (under $1M)tsunami
- 1981M7.7
Apia; American Samoa: Pago Pago
1 Sep 1981 · 266 km away · intensity VI
Limited damage (under $1M)tsunami
- 1977M7.6
Apia
2 Apr 1977 · 160 km away · intensity VI
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.