Reviewed by USGSTonga3y ago
M5.7 earthquake 126 km NNE of Hihifo, Tonga
Saturday, June 17, 2023, 18:44:57 UTC · 14.933°S, 173.269°W
A magnitude 5.7 earthquake struck 126 km NNE of Hihifo, Tonga on Saturday, June 17, 2023, 18:44:57 UTC, at a depth of 8.0 km (shallow). The USGS PAGER alert is green: low likelihood of casualties and damage. It is the strongest earthquake within 300 km since an M7.6 on May 10, 2023.
- Magnitude
- 5.7
- Moderate · mww
- Depth
- 8 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- IV
- Light (ShakeMap)
- PAGER alert
- Green
- Impact estimate
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 75 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
5 kilotons of TNT
That is about 1/3 of the Hiroshima bomb. It released about 11 times the energy of a magnitude 5.0.
Tectonic setting
22 km
from the nearest mapped plate boundary, between the Tonga and Pacific plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
8 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
Modelled from the ShakeMap and population data. Alert level green: low likelihood of casualties and damage.
- III · Weak shaking
- 209,000 people
Estimated shaking in nearby towns
- HihifocapitalPopulation 815III · Weak
- GataivaiPopulation 1,100III · Weak
- AsaucapitalPopulation 6,600III · Weak
- VailoacapitalPopulation 769III · Weak
- LeulumoegacapitalPopulation 1,500III · Weak
- Nofoali`iPopulation 1,800III · Weak
- MulifanuacapitalPopulation 4,500III · Weak
- A'opocapitalPopulation 390III · Weak
After the main event
Aftershocks within 75 km
USGS lists 4 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.4 on June 23, 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 1,654 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 · 140 km SE of this epicenter
- 8.0The 1917 Samoa-Tonga EarthquakeJune 26, 1917 · 7 km S of this epicenter
- 7.8146 km ESE of Hihifo, TongaDecember 26, 1975 · 171 km SE of this epicenter
- 7.7133 km NE of Hihifo, TongaSeptember 1, 1981 · 20 km E of this epicenter
- 7.682 km WNW of Hihifo, TongaMay 10, 2023 · 152 km SW of this epicenter
- 7.6199 km ESE of Hihifo, TongaApril 2, 1977 · 233 km SE of this epicenter
- 7.488 km NNE of Hihifo, TongaApril 7, 1995 · 41 km SW of this epicenter
- 7.2117 km SSW of Hihifo, TongaJanuary 8, 2000 · 245 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 9 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 · 140 km away
192 deaths$285 million damagetsunami
- 1917M8.3
Samoa Islands
26 Jun 1917 · 69 km away
2 deathsModerate damage ($1–5M)tsunami
- 1981M7.7
Apia; American Samoa: Pago Pago
1 Sep 1981 · 20 km away · intensity VI
Limited damage (under $1M)tsunami
- 1977M7.6
Apia
2 Apr 1977 · 233 km away · intensity VI
Limited damage (under $1M)tsunami
- 1975M7.8
Samoa Islands
26 Dec 1975 · 171 km away · intensity V
tsunami
- 2023M7.6
Hihifo
10 May 2023 · 162 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.