Overall Green Earthquake alert in Tonga on 12 Aug 2025 13:41 UTC

GDACS is a cooperation framework between the United Nations, the European Commission and disaster managers worldwide to improve awareness, information exchange and coordination in the first phase after major sudden-onset disasters.

M 5.5 in Tonga on 12 Aug 2025 13:41 UTC

Hazard models

Rapid Impact

Shakemap

Tsunami

Event summary

This earthquake is expected to have a low humanitarian impact based on the magnitude and the affected population and their vulnerability.

Earthquake Magnitude:	5.5M
Depth:	37.7 Km
Lat/Lon:	-15.2764 , -173.3116
Event Date:	12 Aug 2025 13:41 UTC 12 Aug 2025 01:41 Local
Exposed Population:	140 thousand in MMI&>=III
Source:	NEIC us6000r03i
Inserted at:	12 Aug 2025 15:27 UTC
INFORM Coping capacity of the alert score:	1.1 (Tonga)

GDACS Score

For more info on GDACS score click here.

	Earthquake (Shakemap)		GDACS score
NEIC	0		0
us6000r03i	Scaled population (raster)	0
	C1 shakemap	0
	C2 shakemap	0
	Country Vulnerability	0
	INFORM_normalised	0
	Score no CC	0

Maximum expected impact using different data sources.

ShakeMap is a product of the USGS Earthquake Hazards Program in conjunction with the regional seismic networks. ShakeMaps provide near-real-time maps of ground motion and shaking intensity following significant earthquakes.

Episode Timeline

ID	Level	Score	Date	Mag, Depth	MMI*	Population**	Tsunami risk***	Delay (hh:mm)	Source
1654831		0	12 Aug 2025 13:41	5.5M, 35km	3.65	N/A (in MMI>=VII)		00:21	NEIC
1654851		0	12 Aug 2025 13:41	5.5M, 37.7km	3.78	N/A (in MMI>=VII)		01:45	NEIC

The episode that generated the alert; the next major evaluations beyond 12 hours will not trigger additional alerts.

The episode that has the last updated information.

* The max MMI detected for sources having shakemaps;
** The population detected in MMI>=7 for episode with shakemap or in a 100km radius;
*** The tsunami max height.

Exposed population

The earthquake happened in Samoa ,of Samoa (population ) . The alertlevel for this event is GREEN

Intensity	Population
	no people

Shakemaps Timeline

Shake id #	episodeid	Lat/Lon	Magnitude	Depth	Max MMI	Date shake (UTC)	Delay (hh:mm)
1	1654831	-173.329/-15.165	5.5	35	3.871	12 Aug 2025 14:11	00:29	(new episode)
2	1654851	-173.312/-15.276	5.5	37.7	3.996	12 Aug 2025 15:33	01:52	(new episode)
3	1654851	-173.312/-15.276	5.5	37.7	3.996	12 Aug 2025 16:08	02:26	(upd of #2)
4	1654851	-173.312/-15.276	5.5	37.7	3.996	14 Aug 2025 14:01	2d 00:19	(upd of #3)

Affected Provinces

Intensity	Region Province	Country	Population
	Samoa	Samoa	4200 people

Affected populated places. Areas of interest

Name	Country	City class	Population	Distance
Falehau	Tonga	Village	-	87 km
Hihifo	Tonga	Village	<1000 people	90 km
Falelima	Samoa	Village	<1000 people	198 km
Faleaseela	Samoa	Village	-	208 km
Matavanu Crater	Samoa	Village	-	217 km

see full list

Critical infrastructure

Airports, ports, nuclear plants and hydrodams at risk, if affected, are listed below.

Airports

Intensity	Name	IATA Code	Elevation (m)	Usage	Runway type	IFR	Runway Length (ft)	Distance
	Lalomalava	LAV	unknown				0	206 km

More information

For a full list of available products related to this event, please refer to the GDACS Resources page.

Disclaimer
While we try everything to ensure accuracy, this information is purely indicative and should not be used for any decision making without alternate sources of information.
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