Written by on . Last updated February 10th, 2024.

A shallow and significant MAG-5.7 earthquake struck in the South Pacific Ocean 228 kilometer from Nuku‘alofa, Tonga in the night of Wednesday December 13th, 2023. Around 100 thousand people have been exposed to shaking.

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Earthquake Summary

This earthquake hit under water in the South Pacific Ocean, 163 kilometers (101 mi) off the coast of Tonga, 228 kilometer north-east of Nuku‘alofa in Tongatapu. The center of this earthquake had a very shallow depth of 11 km. Shallow earthquakes usually have a larger impact than earthquakes deep in the earth.

Date and Time: Dec 13, 2023 01:54AM (Tongatapu Time)
- Dec 12, 2023 12:54 Universal Time.
Location: 228 km NE of Nuku‘alofa, Tongatapu, Tonga.
Coordinates 20°0'55"S 173°22'13"W.
Map: Map of area around epicenter.
Map of area around epicenter. Click to open in Google Maps.
Magnitude: MAG 5.7
Detected by 17 stations. Maximum Error Range ±0.075 .
Depth: 11 km (7 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 100 thousand people exposed to shaking

An estimated 100 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.

Light shaking and likely no damage may have been experienced by an estimated 4,450 people. At IV, it is the highest MMI level this earthquake has caused. Intensity level III was experienced by the majority of people (around 90 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
7,330
II
Very weak None
86,800
III
Weak Probably none
4,450
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 . The closest significant population center near the earthquake is Nuku‘alofa in Tongatapu, Tonga. Nuku‘alofa is located 228 kilometer (142 mi) north-east of the epicenter. The intensity of shaking and damage in Nuku‘alofa is estimated to be around level III on the Modified Mercalli Intensity scale (weak shaking, probably no damage).

Overview of nearby places

Distance Place Intensity (MMI)
228 km (142 mi)
SW from epicenter
Nuku‘alofa

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

Earthquake Intensity Map

The maximum intensity (MMI Scale) caused by this earthquake is IV. The map below shows in which areas this earthquake was the most and least impactful. It is based on data from the US Geographic Survey.

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.

3 Aftershocks detected

Since this main shock, 3 smaller aftershocks were detected. Just 16 hrs after this main shock, an earthquake measuring MAG-4.6 was detected 21 km (13 mi) southwest of this earthquake.

Overview of foreshocks and aftershocks

Classification Magnitude When Where
Main Shock
This Earthquake
M 5.7 Dec 13, 2023 01:54AM
(Tongatapu Time)
-
Aftershock M 4.6 16 hrs later
Dec 13, 2023 06:01PM (Tongatapu Time)
21 km (13 mi)
SW from Main Shock.
Aftershock M 4.5 19 hrs later
Dec 13, 2023 09:17PM (Tongatapu Time)
39 km (24 mi)
SSE from Main Shock.
Aftershock M 4.3 2 days later
Dec 15, 2023 08:06AM (Tongatapu Time)
26 km (16 mi)
SE from Main Shock.
Detected MAG2.5+ earthquakes within within 100km (62 mi), that occurred in the three days before and after the main shock.

More earthquakes coming?

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.

The chance that a significant earthquake like this one is followed by an even larger earthquake is not so large. On average, scientists estimate a 94% chance that a major earthquake will not be followed by an even larger one. It is still adviced to be aware of this risk

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 December 12th, 2023, when a 5.8 magnitude earthquake hit 299 km (186 mi) further northwest. An even stronger magnitude 7.3 earthquake struck on November 11th, 2022.

In total, 35 earthquakes with a magnitude of 5.7 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 5.7. Earthquakes of this strength are unlikely to trigger a tsunami.
This earthquake occurred at a depth of of 11 km (7 mi). Earthquakes this shallow could trigger a tsunami.

Sources

Last updated 10/02/24 07:29 (). As more information on this earthquake becomes available this article will be updated. This article is automatically composed based on data originating from multiple sources.

  1. US Geographic Society (USGS): Earthquake us7000lict
  2. European-Mediterranean Seismological Centre (EMSC): Earthquake 20231212_0000137
  3. Geonames.org: World Cities Database
  4. Google Maps: Static API
  5. Earthquakelist.org: Historic Earthquakes Database

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