4.4

M4.4 Earthquake 41 km E of Isangel, VanuatuAugust 31, 2021

2021-08-31 22:59:16 UTC (2021-08-31) · approx. 9:59 AM UTC+11 local

MagnitudeM4.4(mb)
Time22:59 UTC9:59 AM UTC+11
Depth228.6 kmintermediate depth
Coordinates-19.518°, 169.672°
Felt byNo felt reports
Status✓ Reviewed by USGS

On August 31, 2021 at 22:59 UTC, a magnitude 4.4 intermediate depth earthquake struck 41 km E of Isangel, Vanuatu, at a depth of 228.6 km and coordinates -19.5176°, 169.6718°.

Physical scale: An earthquake of magnitude 4.4 releases seismic energy equivalent to roughly 60 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 655 m — 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 78 km ESE of Isangel, Vanuatu. Since the mainshock, the USGS has recorded 5 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.

Map showing earthquake epicenter at -19.52°, 169.67°

Earthquake Details

Magnitude
4.4 mb
Depth
228.6 km
intermediate depth
Location
-19.5176°N
169.6718°E

Technical Information

Event ID
us7000f6gj
Event Type
earthquake
Status
✓ Reviewed
Significance
298
Azimuthal Gap
61.0°
Min Station Distance
3.715°
RMS Residual
0.90 sec
Last Updated
2021-11-06 20:28:34 UTC

Common Questions

How strong was the magnitude 4.4 earthquake near Isangel, Vanuatu?

The magnitude 4.4 earthquake that struck 41 km E of Isangel, Vanuatu on August 31, 2021 at 22:59 UTC had a depth of 228.6 km. For context, this was a light earthquake commonly felt near the epicenter.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.4 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 4.4 earthquake is an aftershock of the larger magnitude 5.2 mainshock that occurred earlier 78 km ESE of Isangel, Vanuatu. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.

Understanding This Data

Magnitude 4.4 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us7000f6gj). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, August 31, 2021). M4.4 Earthquake 41 km E of Isangel, VanuatuAugust 31, 2021. Retrieved November 6, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000f6gj/