4.9

M4.9 Earthquake 59 km E of Luganville, Vanuatu — July 5, 2021

2021-07-05 02:23:48 UTC (2021-07-05) · approx. 1:23 PM UTC+11 local

Aftershock of the M5.2 mainshock.

MagnitudeM4.9(mww)
Time02:23 UTC≈ 1:23 PM UTC+11
Depth124.1 kmintermediate depth
Coordinates-15.493°, 167.718°
Felt byNo felt reports
Status✓ Reviewed by USGS

On July 5, 2021 at 02:23 UTC, a magnitude 4.9 intermediate depth earthquake struck 59 km E of Luganville, Vanuatu, at a depth of 124.1 km and coordinates -15.4931°, 167.7183°.

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 5.2 mainshock that occurred 13 days ago 35 km NE of Luganville, 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

Map showing earthquake epicenter at -15.49°, 167.72°

Earthquake Details

Magnitude
4.9 mww
Depth
124.1 km
intermediate depth
Location
-15.4931°N
167.7183°E

Technical Information

Event ID
us7000eirt
Event Type
earthquake
Status
✓ Reviewed
Significance
369
Azimuthal Gap
70.0°
Min Station Distance
0.498°
RMS Residual
0.93 sec
Last Updated
2025-12-22 19:03:36 UTC

Common Questions

How strong was the magnitude 4.9 earthquake near Luganville, Vanuatu?

The magnitude 4.9 earthquake that struck 59 km E of Luganville, Vanuatu on July 5, 2021 at 02:23 UTC had a depth of 124.1 km. For context, this was a light earthquake commonly felt near the epicenter.

Where did the earthquake occur?

The earthquake epicenter was located at -15.4931°, 167.7183°, which is 59 km E of Luganville, Vanuatu. View all earthquakes in Vanuatu.

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 M5.2 one earlier?

No. This magnitude 4.9 earthquake is an aftershock of the larger magnitude 5.2 mainshock that occurred earlier 35 km NE of Luganville, 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 4.9 event is significantly smaller than that historical record.

Authoritative source: USGS event page (event ID: us7000eirt). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, July 5, 2021). M4.9 Earthquake 59 km E of Luganville, Vanuatu — July 5, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000eirt/