Written by on . Last updated April 16th, 2024.

A shallow and significant MAG-5.4 earthquake struck in the South Pacific Ocean 147 kilometer from Nuku‘alofa, Tonga in the evening of Tuesday March 26th, 2024. Shaking may have been felt by a total of 90 thousand people.

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Earthquake Summary

This earthquake hit under water in the South Pacific Ocean, 140 kilometers (87 mi) off the coast of Tonga, 147 kilometer east-northeast of Nuku‘alofa in Tongatapu. The center of this earthquake had a very shallow depth of 10 km. Shallow earthquakes usually have a larger impact than earthquakes deep in the earth.

Date and Time: Mar 26, 2024 10:37PM (Tongatapu Time)
- Mar 26, 2024 09:37 Universal Time.
Location: 147 km ENE of Nuku‘alofa, Tongatapu, Tonga.
Coordinates 20°41'7"S 173°52'24"W.
Map: Map of area around epicenter.
Map of area around epicenter. Click to open in Google Maps.
Magnitude: MAG 5.4
Detected by 12 stations. Maximum Error Range ±0.089 .
Depth: 10 km (6 mi)
A very shallow depth.
Max. Intensity:
IV
Light

On the Modified Mercalli Scale.
Tsunami Risk: Low tsunami risk
Earthquakes under MAG-6.5 do not usually cause tsunami's.
Always stay cautious - More info here.

Minimal impact predicted

Based on scientific estimates by the US Geographic Survey (USGS), the risk of high fatalities for this earthquake is classified at level GREEN (low). They expect an 65% likelyhood of between 0 and 1 fatalities, and a 96% chance that the number of fatalities falls no higher than 10.

The USGS classifies the economic impact of this earthquake at level GREEN (low). They expect an 65% likelyhood of between 0 and 1 million US Dollars in economic damage and impact, and a 96% chance that the economic impact of this earthquake falls no higher than 10 million USD.

Roughly 90 thousand people exposed to shaking

An estimated 90 thousand have been exposed to shaking (An MMI or Modified Mercalli Intensity level II or higher) as a result of this earthquake according scientific estimates published by the USGS.

The highest earthquake impact level for this earthquake is III, which corresponds with weak shaking and probably no damage. Roughly 86,950 people are expected to be exposed to this level. All exposure to shaking was within the borders of Tonga .

People MMI Level Shaking Damage
0
I
Not noticable None
5,770
II
Very weak None
86,950
III
Weak Probably none
0
IV
Light Likely none
0
V
Moderate Very light
0
VI
Strong Light
0
VII
Very Strong Moderate
0
VIII
Severe Moderate to heavy
0
IX
Violent Heavy
0
X
Extreme Very heavy

Nearby towns and cities

This earthquake may have been felt in Tonga . Located 147 kilometer (91 mi) east-northeast of the epicenter of this earthquake, Nuku‘alofa (Tongatapu, Tonga) is the nearest significant population center. Nuku‘alofa experienced an earthquake intensity (MMI Scale) of roughly III. That level implies weak shaking and probably no damage.

Overview of nearby places

Distance Place Intensity (MMI)
147 km (91 mi)
WSW from epicenter
Nuku‘alofa

Tongatapu, Tonga.
III
Weak
Cities and Towns around the epicenter of this earthquake.

Earthquake Intensity Map

The intensity in shaking and damage by this earthquake is illustrated through the map below. The highest intensity measured for this earthquake is III.

I Not felt
II Weak
III Weak
IV Light
V Moderate
VI Strong
VII Very Strong
VIII Severe
IX Violent
X Extreme
Earthquake Intensity Map based on Shakemap Data provided by USGS.

Risk of aftershocks?

We monitor for foreshocks or aftershocks that have a magnitude of 2.5+ and occur within 100km (62 mi) of the epicenter of this earthquake. So far no such earthquakes have been detected.

Aftershocks are usually at least 1 order of magnitude less strong than main shocks. The more time passes, the smaller the chance and likely strength of any potential aftershocks.

In only six percent of cases, significant earthquakes are followed by a larger main shock, making the current earthquake a foreshock. While the chance of this happening is not so large, it is adviced to maintain cautiousness in the hours and days following a major earthquake.

Read: How to Stay Safe during an Earthquake (cdc.gov).

Earthquakes like this happen often in the region

Earthquakes of this strength are very common in the region. This is the strongest earthquake to hit since January 18th, 2024, when a 6.4 magnitude earthquake hit 255 km (159 mi) further northwest. An even stronger magnitude 7.3 earthquake struck on November 11th, 2022.

In total, 120 earthquakes with a magnitude of 5.4 or higher have been registered within 300km (186 mi) of this epicenter in the past 10 years. This comes down to an average of once every 30 days.

Low tsunami risk

DISCLAIMER: We strongly suggest to closely monitor advice from local authorities with regards to tsunami risks. Our analysis is based on automatically collected data from external sources, and these might contain mistakes. In addition, earthquakes can cause landslides that may lead to a tsunami, or be a followed by another, potentially stonger, earthquake.

Based on early data it appears this earthquake was not strong enough (lower than MAG-6.5) to be likely to cause destructive tsunami's. However this earthquake appeared to have hit at a shallow depth under sea, so stay cautious and monitor advice from local authorities.

Tsunami Risk Factors

Factor Under Sea? MAG-6.5 or stronger? Shallow depth?
Explanation Almost all tsunami's are caused by earthquakes with their epicenter under sea or very near the sea. However stay cautious in coastal areas as earthquakes on land may cause landslides into sea, potentially still causing a local tsunami. Under MAG 6.5: Very unlikely to cause a tsunami.
MAG 6.5 to 7.5: Destructive tsunami's do occur, but are uncommon. Likely to observe small sea level changes.
MAG 7.6+: Earthquakes with these magnitudes might produce destructive tsunami's.
Most destructive tsunami's are caused by shallow earthquakes with a depth between 0 and 100km under the surface of the earth. Deeper tsunami's are unlikely to displace to ocean floor.
This Earthquake This earthquake appears to have struck under the sea. Not this earthquake.
This earthquake had a magnitude of 5.4. Earthquakes of this strength are unlikely to trigger a tsunami.
This earthquake occurred at a depth of of 10 km (6 mi). Earthquakes this shallow could trigger a tsunami.

Sources

Last updated 16/04/24 12:28 (). This article contains currently available information about the earthquake and is automatically composed. We continue to update this article up to a few days after the earthquake occurred.

  1. US Geographic Society (USGS): Earthquake us7000m826
  2. European-Mediterranean Seismological Centre (EMSC): Earthquake 20240326_0000102
  3. Geonames.org: World Cities Database
  4. Google Maps: Static API
  5. Earthquakelist.org: Historic Earthquakes Database

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