On Wednesday Morning a Shallow M6.6 Earthquake struck in the South Pacific Ocean 308km from Nuku‘alofa (Tonga).

Written by Earthquakelist.org on October 1st, 2024. Last updated November 30th, 2024.

A shallow and strong M6.6 earthquake struck in the South Pacific Ocean 308 kilometer from Nuku‘alofa, Tonga in the morning of Wednesday October 2nd, 2024. The USGS has indicated there is a potential risk at tsunami's following this earthquake.

Earthquake Summary

This earthquake hit under water in the South Pacific Ocean, 124 kilometers (77 mi) off the coast of Tonga, 308 kilometer north-east 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:	Oct 2, 2024 09:05AM (Tongatapu Time) - Oct 1, 2024 20:05 Universal Time.
Location:	308 km NE of Nuku‘alofa, Tongatapu, Tonga. Coordinates 19°17'19"S 173°0'3"W.
Map:	Map of area around epicenter. Click to open in Google Maps.
Magnitude:	MAG 6.6 Detected by 10 stations. Maximum Error Range ±0.035 .
Depth:	10 km (6 mi) A very shallow depth.
Max. Intensity:	V Moderate On the Modified Mercalli Scale.
Tsunami Risk:	Potential tsunami risk The USGS has indicated there is a potential risk at tsunami's following this earthquake. Always stay cautious - More info here.

Potential 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.

There is a potential tsunami risk in the aftermath of this earthquake, immediately evacuate to higher grounds away from coastal areas and monitor advice from local authorities. The US Geographic Survey organization has indicated a potential risk for tsunami's following this earthquake.

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.	This earthquake had a magnitude of 6.6. Earthquakes of this strength could trigger a tsunami.	This earthquake occurred at a depth of of 10 km (6 mi). Earthquakes this shallow could trigger a tsunami.

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 20 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 20 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 21,170 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
0	II	Very weak	None
270	III	Weak	Probably none
21,170	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 308 kilometer (191 mi) north-east of the epicenter of this earthquake, Nuku‘alofa (Tongatapu, Tonga) is the nearest significant population center.

Overview of nearby places

Cities and Towns around the epicenter of this earthquake.
Distance	Place
308 km (191 mi) SW from epicenter	Nuku‘alofa Tongatapu, Tonga.
325 km (202 mi) E from epicenter	Alofi All regions, Niue.

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.

Shaking reported by 2 people

People that feel an earthquake may report their experience to the US Geographic Survey. Currently, 2 people have reported shaking in 2 places in Tonga.We keep updating this article as more ground reports become available. You may report that you felt this earthquake here.

Places with most reports:

Pangai, Haʿapai, Tonga: 1 person.
Nukuʿalofa, Tongatapu, Tonga: 1 person.

5 Aftershocks detected

After this earthquake struck, 5 smaller aftershocks occurred. Just 3 days after this main shock, an earthquake measuring MAG-4.9 was detected 47 km (29 mi) east of this earthquake.

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
Main Shock This Earthquake	M 6.6	Oct 2, 2024 09:05AM (Tongatapu Time)	-
Aftershock	M 4.3	34 mins later Oct 2, 2024 09:39AM (Tongatapu Time)	78 km (48 mi) NNE from Main Shock.
Aftershock	M 4.7	3 hrs later Oct 2, 2024 11:45AM (Tongatapu Time)	33 km (21 mi) NE from Main Shock.
Aftershock	M 4.7	5 hrs later Oct 2, 2024 01:51PM (Tongatapu Time)	38 km (24 mi) NE from Main Shock.
Aftershock	M 4.9	3 days later Oct 5, 2024 01:16AM (Tongatapu Time)	47 km (29 mi) E from Main Shock.
Aftershock	M 4.7	3 days later Oct 5, 2024 01:34AM (Tongatapu Time)	50 km (31 mi) NE from Main Shock.

More earthquakes coming?

The risk of aftershocks decreases rapidly over time. Usually, aftershocks are at least one order of magnitude lower than a main shock.

It's always adviced to be cautious of the risk of a larger shock following any significant earthquake, however this risk is fairly small. There is a roughly 94 percent change that no larger main shock will follow in the days following this earthquake.

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

Earthquakes like this are common in the region

Earthquakes of this strength occur quite regularly in the region. This is the strongest earthquake to hit since August 25th, 2024, when a 6.9 magnitude earthquake hit 225 km (140 mi) further west-southwest. An even stronger magnitude 7.3 earthquake struck on November 11th, 2022.

In total, 3 earthquakes with a magnitude of 6.6 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 years.

Sources

Last updated 30/11/24 04:38 (). 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.