4.0

M4.0 Earthquake south of Tonga — June 18, 2023

2023-06-18 21:26:30 UTC (2023-06-18) · approx. 9:26 AM UTC-12 local

MagnitudeM4.0(mb)
Time21:26 UTC≈ 9:26 AM UTC-12
Depth10.0 kmshallow crustal
Coordinates-24.208°, -175.379°
Felt byNo felt reports
Status✓ Reviewed by USGS

On June 18, 2023 at 21:26 UTC, a magnitude 4.0 shallow crustal earthquake struck south of Tonga, at a depth of 10.0 km and coordinates -24.2083°, -175.3792°.

Physical scale: An earthquake of magnitude 4.0 releases seismic energy equivalent to roughly 15 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 347 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at -24.21°, -175.38°

Earthquake Details

Magnitude
4.0 mb
Depth
10.0 km
shallow crustal
Location
-24.2083°N
-175.3792°E

Technical Information

Event ID
us6000kn93
Event Type
earthquake
Status
✓ Reviewed
Significance
246
Stations Used
12
Azimuthal Gap
98.0°
Min Station Distance
3.029°
RMS Residual
0.54 sec
Last Updated
2023-08-26 20:54:17 UTC

Common Questions

How strong was the magnitude 4.0 earthquake south of Tonga?

The magnitude 4.0 earthquake that struck south of Tonga on June 18, 2023 at 21:26 UTC had a depth of 10.0 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 4.0 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 4.0 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us6000kn93). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2023, June 18, 2023). M4.0 Earthquake south of Tonga — June 18, 2023. Retrieved August 26, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000kn93/