Written by on . Last updated November 21st, 2023.

In the morning of Saturday September 23rd, 2023, a Magnitude 4.8 earthquake hit in the South Pacific Ocean 263 kilometer from Nuku‘alofa, Tonga.

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Earthquake Summary

This earthquake hit under water in the South Pacific Ocean, 41 kilometers (25 mi) off the coast of Tonga, 263 kilometer north-northeast of Nuku‘alofa in Tongatapu. The center of this earthquake had an intermediate depth of 132 km.

Date and Time: Sep 23, 2023 11:13AM (Tongatapu Time)
- Sep 22, 2023 22:13 Universal Time.
Location: 263 km NNE of Nuku‘alofa, Tongatapu, Tonga.
Coordinates 18°55'36"S 174°18'53"W.
Map: Map of area around epicenter.
Map of area around epicenter. Click to open in Google Maps.
Magnitude: MAG 4.8
Detected by 84 stations. Maximum Error Range ±0.061 .
Depth: 132 km (82 mi)
An intermediate depth.
Tsunami Risk: Tsunami very unlikely
Earthquakes under MAG-6.5 at depths deeper than 100km are very unlikely to cause tsunami's.
Always stay cautious - More info here.

Nearby towns and cities

This earthquake may have been felt in Tonga . Located 263 kilometer (163 mi) north-northeast of the epicenter of this earthquake, Nuku‘alofa (Tongatapu, Tonga) is the nearest significant population center.

Overview of nearby places

Distance Place
263 km (163 mi)
SSW from epicenter
Nuku‘alofa

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

Shaking reported by 1 person

People that feel an earthquake may report their experience to the US Geographic Survey. Currently, 1 person has reported shaking in one place 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:

  • Neiafu, Vavaʿu, Tonga: 1 person.

Risk of aftershocks?

This earthquake did not have any significant foreshocks nor aftershocks occurring within 100km (62 mi) of its epicenter.

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 September 8th, 2023, when a 5.2 magnitude earthquake hit 131 km (81 mi) further west. An even stronger magnitude 7.3 earthquake struck on November 11th, 2022.

In total, 833 earthquakes with a magnitude of 4.8 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 4 days.

Tsunami very unlikely

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.

For a serious tsunami to occur, earthquakes usually need to have a magnitude of at least 6.5 and occur at a shallow depth of maximum 100km. Neither are the case with this earthquake. However always 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 4.8. Earthquakes of this strength are unlikely to trigger a tsunami.
Not this earthquake.
This earthquake occurred at a depth of 132 km (82 mi). Earthquakes this deep in the earth are unlikely to trigger a tsunami.

Sources

Last updated 21/11/23 12:08 (). 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.

  1. US Geographic Society (USGS): Earthquake us7000kxjb
  2. European-Mediterranean Seismological Centre (EMSC): Earthquake 20230922_0000223
  3. Geonames.org: World Cities Database
  4. Google Maps: Static API
  5. Earthquakelist.org: Historic Earthquakes Database

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