M5.4 earthquake 123 km NE of Hihifo, Tonga

Friday, June 23, 2023, 19:06:16 UTC · 15.157°S, 172.988°W

A magnitude 5.4 earthquake struck 123 km NE of Hihifo, Tonga on Friday, June 23, 2023, 19:06:16 UTC, at a depth of 35.0 km (shallow). USGS received 3 “Did You Feel It?” reports, with a maximum reported intensity of III (weak). The USGS PAGER alert is green: low likelihood of casualties and damage. It is the strongest earthquake within 300 km since an M5.7 on June 17, 2023.

Magnitude: 5.4; Moderate · mww
Depth: 35 km; Shallow
Felt reports: 3; Max intensity III
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

2 kilotons of TNT

That is about 1/8 of the Hiroshima bomb. It released about 4 times the energy of a magnitude 5.0.

Tectonic setting

26 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

35 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

Reports sent by people to USGS, grouped by place (most reports first). Intensity uses the Modified Mercalli scale (I–X): what people felt, not the magnitude.

Place	Intensity	Reports	Distance
Apia, Apia Urban Area, Samoa	III · Weak	1	200 km
Avao, Savaii, Samoa	II · Weak	1	203 km
96799<br>0.330	II · Weak	1	265 km

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
LotofagaPopulation 1,100III · Weak
GataivaiPopulation 1,100III · Weak
LeulumoegacapitalPopulation 1,500III · Weak
Nofoali`iPopulation 1,800III · Weak
AfengaPopulation 1,900III · Weak
VailoacapitalPopulation 769III · Weak
MulifanuacapitalPopulation 4,500III · Weak

After the main event

Aftershocks within 75 km

USGS lists 1 M2.5+ earthquake within 75 km in the following 30 days; the largest was M4.5 on July 12, 2023. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

4.563 km NNE of Hihifo, Tonga3y ago · 68 km SW of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 1,719 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 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 · 103 km away
192 deaths$285 million damagetsunami
1917M8.3
Samoa Islands
26 Jun 1917 · 38 km away
2 deathsModerate damage ($1–5M)tsunami
1981M7.7
Apia; American Samoa: Pago Pago
1 Sep 1981 · 24 km away · intensity VI
Limited damage (under $1M)tsunami
1977M7.6
Apia
2 Apr 1977 · 196 km away · intensity VI
Limited damage (under $1M)tsunami
1975M7.8
Samoa Islands
26 Dec 1975 · 135 km away · intensity V
tsunami
2023M7.6
Hihifo
10 May 2023 · 181 km away

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers