Shallow M5.9 Earthquake struck on Monday Night in the South Pacific Ocean 155km from Nuku‘alofa (Tonga).

Written by Earthquakelist.org on March 30th, 2025. Last updated April 27th, 2025.

A shallow and significant Magnitude 5.9 earthquake struck in the South Pacific Ocean 155 kilometer from Nuku‘alofa, Tonga in the night of Monday March 31st, 2025. Around 100 thousand people have been exposed to shaking.

Earthquake Summary

This earthquake hit under water in the South Pacific Ocean, 148 kilometers (92 mi) off the coast of Tonga, 155 kilometer north-east of Nuku‘alofa in Tongatapu. The center of this earthquake had a quite shallow depth of 27 km. Shallow earthquakes usually have a larger impact than earthquakes deep in the earth.

Date and Time:	Mar 31, 2025 04:33AM (Tongatapu Time) - Mar 30, 2025 15:33 Universal Time.
Location:	155 km NE of Nuku‘alofa, Tongatapu, Tonga. Coordinates 20°13'30"S 174°4'53"W.
Map:	Map of area around epicenter. Click to open in Google Maps.
Magnitude:	MAG 5.9 Detected by 8 stations. Maximum Error Range ±0.11 .
Depth:	27 km (17 mi) A quite shallow depth.
Max. Intensity:	V Moderate 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 100 thousand people exposed to shaking

The USGS has published a report estimating the number of people exposed to this earthquake. Acoording to their analysis, roughly 100 thousand have been exposed to shaking at an MMI level of II or higher.

The highest earthquake impact level for this earthquake is IV, which corresponds with light shaking and likely no damage. Roughly 22,810 people are expected to be exposed to this level. Intensity level III was experienced by the majority of people (around 80 thousand). In their region, weak shaking and probably no damage can be expected. All exposure to shaking was within the borders of Tonga .

People	MMI Level	Shaking	Damage
0	I	Not noticable	None
0	II	Very weak	None
82,000	III	Weak	Probably none
22,810	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 . Nuku‘alofa in Tongatapu, Tonga is the nearest significant place from the epicenter. The earthquake occurred 155 kilometer (96 mi) north-east of Nuku‘alofa. The intensity of shaking and damage in Nuku‘alofa is estimated to be around level IV on the Modified Mercalli Intensity scale (light shaking, likely no damage).

Overview of nearby places

Cities and Towns around the epicenter of this earthquake.
Distance	Place	Intensity (MMI)
155 km (96 mi) SW from epicenter	Nuku‘alofa Tongatapu, Tonga.	IV Light

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 IV.

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.

18 Aftershocks detected

This main shock was followed by 18 smaller aftershocks. Just 3 hrs after this main shock, an earthquake measuring MAG-6.2 was detected 11 km (7 mi) south-east of this earthquake.

In the days before this main shock, 1 smaller foreshock was detected. Nearby this earthquake a foreshock struck 2 days earlier. It measured a magnitude of 4.7

Overview of foreshocks and aftershocks

Detected MAG2.5+ earthquakes within within 100km (62 mi), that occurred in the three days before and after the main shock.
Classification	Magnitude	When	Where
Foreshock	M 4.7	2 days earlier Mar 29, 2025 02:24AM (Tongatapu Time)	23 km (14 mi) SSE from Main Shock.
Main Shock	M 7.0	Mar 31, 2025 01:18AM (Tongatapu Time)	-
Aftershock	M 4.5	36 mins later Mar 31, 2025 01:54AM (Tongatapu Time)	39 km (24 mi) E from Main Shock.
Aftershock	M 4.4	1 hr later Mar 31, 2025 02:24AM (Tongatapu Time)	37 km (23 mi) ESE from Main Shock.
Aftershock	M 4.9	2 hrs later Mar 31, 2025 03:24AM (Tongatapu Time)	25 km (16 mi) ENE from Main Shock.
Aftershock	M 4.7	3 hrs later Mar 31, 2025 03:58AM (Tongatapu Time)	32 km (20 mi) ENE from Main Shock.
Aftershock	M 6.2	3 hrs later Mar 31, 2025 04:04AM (Tongatapu Time)	11 km (7 mi) SE from Main Shock.
Aftershock	M 5.0	3 hrs later Mar 31, 2025 04:26AM (Tongatapu Time)	59 km (37 mi) ESE from Main Shock.
Aftershock	M 4.9	3 hrs later Mar 31, 2025 04:26AM (Tongatapu Time)	37 km (23 mi) E from Main Shock.
Aftershock	M 4.4	3 hrs later Mar 31, 2025 04:42AM (Tongatapu Time)	21 km (13 mi) NE from Main Shock.
Aftershock	M 4.8	4 hrs later Mar 31, 2025 05:10AM (Tongatapu Time)	28 km (17 mi) E from Main Shock.
Aftershock	M 4.3	7 hrs later Mar 31, 2025 08:20AM (Tongatapu Time)	71 km (44 mi) SSE from Main Shock.
Aftershock	M 4.6	7 hrs later Mar 31, 2025 08:30AM (Tongatapu Time)	21 km (13 mi) E from Main Shock.
Aftershock	M 5.2	10 hrs later Mar 31, 2025 10:51AM (Tongatapu Time)	14 km (9 mi) E from Main Shock.
Aftershock	M 4.7	12 hrs later Mar 31, 2025 01:23PM (Tongatapu Time)	40 km (25 mi) SE from Main Shock.
Aftershock	M 4.3	13 hrs later Mar 31, 2025 02:47PM (Tongatapu Time)	70 km (43 mi) SSE from Main Shock.
Aftershock	M 4.9	1 day later Apr 1, 2025 02:20AM (Tongatapu Time)	42 km (26 mi) SE from Main Shock.
Aftershock	M 4.9	1 day later Apr 1, 2025 11:25AM (Tongatapu Time)	60 km (38 mi) ESE from Main Shock.
Aftershock	M 4.6	2 days later Apr 1, 2025 08:37PM (Tongatapu Time)	27 km (17 mi) ENE from Main Shock.
Aftershock	M 4.9	3 days later Apr 2, 2025 01:59PM (Tongatapu Time)	38 km (24 mi) ESE from Main Shock.

More earthquakes coming?

Earthquakes can create aftershocks. These are generally at least 1 magnitude lower than any main shock, and as time passes the chance and strength of aftershocks decreases.

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 March 30th, 2025, when a 6.2 magnitude earthquake hit 19 km (12 mi) further south-southeast. An even stronger magnitude 7.3 earthquake struck on November 11th, 2022.

In total, 38 earthquakes with a magnitude of 5.9 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 3 months.

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 5.9. Earthquakes of this strength are unlikely to trigger a tsunami.	This earthquake occurred at a depth of of 27 km (17 mi). Earthquakes this shallow could trigger a tsunami.

Sources

Last updated 27/04/25 18:48 (). This article is automatically generated based on available data. We keep checking multiple sources for additional information. This article gets updated as new details on this earthquake become available.