M4.9 Earthquake 139 km SSW of Gataivai, Samoa — May 23, 2026
2026-05-23 23:54:27 UTC (2026-05-23) · approx. 11:54 AM UTC-12 local
Aftershock of the M5.0 mainshock.
On May 23, 2026 at 23:54 UTC, a magnitude 4.9 shallow crustal earthquake struck 139 km SSW of Gataivai, Samoa, at a depth of 10.0 km and coordinates -14.8846°, -172.9976°. This earthquake was detected by 33 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 369, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.9 releases seismic energy equivalent to roughly 338 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.4 km — a useful intuition for the size of the slip patch on the fault.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.0 mainshock that occurred 5 days ago 141 km SSW of Gataivai, Samoa. Since the mainshock, the USGS has recorded 0 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
Earthquake Details
-172.9976°E
Technical Information
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Common Questions
How strong was the magnitude 4.9 earthquake near Gataivai, Samoa?
The magnitude 4.9 earthquake that struck 139 km SSW of Gataivai, Samoa on May 23, 2026 at 23:54 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -14.8846°, -172.9976°, which is 139 km SSW of Gataivai, Samoa.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.9 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.0 one earlier?
No. This magnitude 4.9 earthquake is an aftershock of the larger magnitude 5.0 mainshock that occurred earlier 141 km SSW of Gataivai, Samoa. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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Location
Authoritative source: USGS event page (event ID: us6000szu1). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, May 23, 2026). M4.9 Earthquake 139 km SSW of Gataivai, Samoa — May 23, 2026. Retrieved June 8, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000szu1/