M5.5 Earthquake 164 km NE of Georgetown, Saint Helena — June 20, 2026
2026-06-20 06:43:17 UTC (2026-06-20) · approx. 5:43 AM UTC-1 local
On June 20, 2026 at 06:43 UTC, a magnitude 5.5 shallow crustal earthquake struck 164 km NE of Georgetown, Saint Helena, at a depth of 10.0 km and coordinates -7.0378°, -13.2186°. The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. This earthquake was detected by 116 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 465, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 5.5 releases seismic energy equivalent to roughly 3 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 3.8 km — a useful intuition for the size of the slip patch on the fault.
ShakeMap — predicted shaking intensity
Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
Population exposure (USGS PAGER)
Estimated population that experienced each level of shaking. Based on the USGS PAGER rapid impact assessment, which combines ShakeMap output with global population grids.
| Shaking intensity (MMI) | Description | Population exposed |
|---|---|---|
| MMI 3 | weak | 1,116 |
Earthquake Details
-13.2186°E
Technical Information
Common Questions
How strong was the magnitude 5.5 earthquake near Georgetown, Saint Helena?
The magnitude 5.5 earthquake that struck 164 km NE of Georgetown, Saint Helena on June 20, 2026 at 06:43 UTC had a depth of 10.0 km. For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at -7.0378°, -13.2186°, which is 164 km NE of Georgetown, Saint Helena.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.5 earthquakes can continue for days to weeks and gradually diminish over time.
Actions
Authoritative source: USGS event page (event ID: us7000susv). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, June 20, 2026). M5.5 Earthquake 164 km NE of Georgetown, Saint Helena — June 20, 2026. Retrieved July 26, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000susv/