In the early morning of Thursday September 7th, 2023, a shallow MAG-4.8 earthquake hit in the South Pacific Ocean 246 kilometer from Nuku‘alofa, Tonga.
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Earthquake Summary
This earthquake hit under water in the South Pacific Ocean, 169 kilometers (105 mi) off the coast of Tonga, 246 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: | Sep 7, 2023 06:03AM (Tongatapu Time) - Sep 6, 2023 17:03 Universal Time. |
|---|---|
| Location: | 246 km ENE of Nuku‘alofa, Tongatapu, Tonga. Coordinates 19°58'26"S 173°11'24"W. |
| Map: |  Map of area around epicenter. Click to open in Google Maps. |
| Magnitude: | MAG 4.8 Detected by 20 stations. Maximum Error Range ±0.124 . |
| Depth: | 10 km (6 mi) A very shallow depth. |
| Tsunami Risk: | Low tsunami risk Earthquakes under MAG-6.5 do not usually cause tsunami's. Always stay cautious - More info here. |
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 246 kilometer (153 mi) east-northeast of Nuku‘alofa.
Overview of nearby places
| Distance | Place |
|---|---|
| 246 km (153 mi) WSW from epicenter |
Nuku‘alofa Tongatapu, Tonga. |
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.
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 happen often in the region
Earthquakes of this strength are very common in the region. This is the strongest earthquake to hit since August 31st, 2023, when a 4.8 magnitude earthquake hit 236 km (147 mi) further west. An even stronger magnitude 7.3 earthquake struck on November 11th, 2022.
In total, 711 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 5 days.
Low tsunami risk
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 4.8. 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 05/11/23 15:58 (). 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.
- US Geographic Society (USGS): Earthquake us7000ktpz
- European-Mediterranean Seismological Centre (EMSC): Earthquake 20230906_0000179
- Geonames.org: World Cities Database
- Google Maps: Static API
- Earthquakelist.org: Historic Earthquakes Database
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