Reviewed by USGSTonga3y ago
M4.2 earthquake 93 km WSW of Hihifo, Tonga
Wednesday, May 31, 2023, 07:39:54 UTC · 16.402°S, 174.536°W
A magnitude 4.2 earthquake struck 93 km WSW of Hihifo, Tonga on Wednesday, May 31, 2023, 07:39:54 UTC, at a depth of 175.2 km (intermediate).
- Magnitude
- 4.2
- Light · mb
- Depth
- 175 km
- Intermediate
- 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
30 tons of TNT
That is about 1/500 of the Hiroshima bomb. A magnitude 5.0 releases about 16 times more energy.
Tectonic setting
4 km
from the nearest mapped plate boundary, between the Tonga and Niuafo'ou plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: intermediate
175 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 50 km
USGS has not published any M2.5+ earthquake within 50 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 2,311 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.12009 Samoa EarthquakeSeptember 29, 2009 · 280 km E of this epicenter
- 8.0The 1917 Samoa-Tonga EarthquakeJune 26, 1917 · 207 km NE of this epicenter
- 7.8146 km ESE of Hihifo, TongaDecember 26, 1975 · 221 km E of this epicenter
- 7.7133 km NE of Hihifo, TongaSeptember 1, 1981 · 223 km NE of this epicenter
- 7.682 km WNW of Hihifo, TongaMay 10, 2023 · 86 km N of this epicenter
- 7.6199 km ESE of Hihifo, TongaApril 2, 1977 · 262 km E of this epicenter
- 7.488 km NNE of Hihifo, TongaApril 7, 1995 · 172 km NE of this epicenter
- 7.3201 km ENE of Neiafu, TongaOctober 6, 1987 · 299 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 10 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 · 280 km away
192 deaths$285 million damagetsunami
- 1917M8.3
Samoa Islands
26 Jun 1917 · 192 km away
2 deathsModerate damage ($1–5M)tsunami
- 1981M7.7
Apia; American Samoa: Pago Pago
1 Sep 1981 · 223 km away · intensity VI
Limited damage (under $1M)tsunami
- 1977M7.6
Apia
2 Apr 1977 · 262 km away · intensity VI
Limited damage (under $1M)tsunami
- 1975M7.8
Samoa Islands
26 Dec 1975 · 221 km away · intensity V
tsunami
- 2023M7.6
Hihifo
10 May 2023 · 90 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.