4.7

M4.7 Earthquake 87 km NE of Georgetown, Saint Helena — July 1, 2024

2024-07-01 13:20:04 UTC (2024-07-01) · approx. 12:20 PM UTC-1 local

Aftershock of the M5.0 mainshock.

MagnitudeM4.7(mb)
Time13:20 UTC≈ 12:20 PM UTC-1
Depth10.0 kmshallow crustal
Coordinates-7.414°, -13.805°
Felt byNo felt reports
Status✓ Reviewed by USGS

On July 1, 2024 at 13:20 UTC, a magnitude 4.7 shallow crustal earthquake struck 87 km NE of Georgetown, Saint Helena, at a depth of 10.0 km and coordinates -7.4138°, -13.8045°. This earthquake was detected by 18 seismic stations with good location accuracy and was assigned a USGS significance rating of 340, placing it among routine seismic activity.

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 5.0 mainshock that occurred 15 days ago 103 km ENE of Georgetown, Saint Helena. 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 -7.41°, -13.80°

Earthquake Details

Magnitude
4.7 mb
Depth
10.0 km
shallow crustal
Location
-7.4138°N
-13.8045°E

Technical Information

Event ID
us7000mxtl
Event Type
earthquake
Status
✓ Reviewed
Significance
340
Stations Used
18
Azimuthal Gap
137.0°
Min Station Distance
0.754°
RMS Residual
0.67 sec
Last Updated
2024-09-12 21:52:31 UTC

Common Questions

How strong was the magnitude 4.7 earthquake near Georgetown, Saint Helena?

The magnitude 4.7 earthquake that struck 87 km NE of Georgetown, Saint Helena on July 1, 2024 at 13:20 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.

Where did the earthquake occur?

The earthquake epicenter was located at -7.4138°, -13.8045°, which is 87 km NE of Georgetown, Saint Helena.

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 M5.0 one earlier?

No. This magnitude 4.7 earthquake is an aftershock of the larger magnitude 5.0 mainshock that occurred earlier 103 km ENE of Georgetown, Saint Helena. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.

Actions

View on USGSDid You Feel It?

Authoritative source: USGS event page (event ID: us7000mxtl). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2024, July 1, 2024). M4.7 Earthquake 87 km NE of Georgetown, Saint Helena — July 1, 2024. Retrieved September 12, 2024 from https://www.earthquaketracker.org/earthquakes/event/us7000mxtl/