M4.7 Earthquake 33 km E of Port-Olry, Vanuatu — December 23, 2021
2021-12-23 00:47:03 UTC (2021-12-23) · approx. 11:47 AM UTC+11 local
Aftershock of the M5.2 mainshock.
On December 23, 2021 at 00:47 UTC, a magnitude 4.7 intermediate depth earthquake struck 33 km E of Port-Olry, Vanuatu, at a depth of 116.5 km and coordinates -14.9837°, 167.3820°.
Physical scale: An earthquake of magnitude 4.7 releases seismic energy equivalent to roughly 169 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.1 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 5.2 mainshock that occurred 3 days ago 43 km ESE of Port-Olry, Vanuatu. 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.
The epicenter is located in Vanuatu, a region characterized by the New Hebrides subduction zone, where the Australian Plate subducts eastward at approximately 90 mm per year. View all earthquakes in Vanuatu.
Learn more: Magnitude scale · Aftershock sequences
Earthquake Details
167.3820°E
Technical Information
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Common Questions
How strong was the magnitude 4.7 earthquake near Port-Olry, Vanuatu?
The magnitude 4.7 earthquake that struck 33 km E of Port-Olry, Vanuatu on December 23, 2021 at 00:47 UTC had a depth of 116.5 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -14.9837°, 167.3820°, which is 33 km E of Port-Olry, Vanuatu. View all earthquakes in Vanuatu.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.7 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.2 one earlier?
No. This magnitude 4.7 earthquake is an aftershock of the larger magnitude 5.2 mainshock that occurred earlier 43 km ESE of Port-Olry, Vanuatu. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
Has Vanuatu had earthquakes this big before?
The largest recorded earthquake in Vanuatu was the M7.9 Vanuatu earthquake of October 7, 2009. Today's magnitude 4.7 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: us6000geq2). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, December 23, 2021). M4.7 Earthquake 33 km E of Port-Olry, Vanuatu — December 23, 2021. Retrieved March 1, 2022 from https://www.earthquaketracker.org/earthquakes/event/us6000geq2/