4.4

M4.4 Earthquake south of the Fiji IslandsSeptember 27, 2023

2023-09-27 23:43:11 UTC (2023-09-27) · approx. 11:43 AM UTC-12 local

MagnitudeM4.4(mb)
Time23:43 UTC11:43 AM UTC-12
Depth579.6 kmdeep-focus
Coordinates-22.186°, -179.537°
Felt byNo felt reports
Status✓ Reviewed by USGS

On September 27, 2023 at 23:43 UTC, a magnitude 4.4 deep-focus earthquake struck south of the Fiji Islands, at a depth of 579.6 km and coordinates -22.1861°, -179.5367°.

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 5.1 mainshock that occurred 23 days ago south of the Fiji Islands. 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.

Map showing earthquake epicenter at -22.19°, -179.54°

Earthquake Details

Magnitude
4.4 mb
Depth
579.6 km
deep-focus
Location
-22.1861°N
-179.5367°E

Technical Information

Event ID
us6000lb8t
Event Type
earthquake
Status
✓ Reviewed
Significance
298
Stations Used
72
Azimuthal Gap
102.0°
Min Station Distance
4.155°
RMS Residual
0.56 sec
Last Updated
2023-12-09 22:00:40 UTC

Common Questions

How strong was the magnitude 4.4 earthquake south of the Fiji Islands?

The magnitude 4.4 earthquake that struck south of the Fiji Islands on September 27, 2023 at 23:43 UTC had a depth of 579.6 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 M5.1 one earlier?

No. This magnitude 4.4 earthquake is an aftershock of the larger magnitude 5.1 mainshock that occurred earlier south of the Fiji Islands. 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: us6000lb8t). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2023, September 27, 2023). M4.4 Earthquake south of the Fiji IslandsSeptember 27, 2023. Retrieved December 9, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000lb8t/