M4.3 earthquake 20 km NE of Argostólion, Ionian Islands, Greece
A magnitude 4.3 earthquake struck 20 km NE of Argostólion, Ionian Islands, Greece at 02:57 local time (23:57 UTC) on 17 Oct 2026, at a depth of 10 km, according to USGS and GFZ.
Reported by 2 agencies · 6 reports to USGS “Did You Feel It?”
Data: USGS, GFZ · updated 2026-11-03 05:57 UTC · reviewed
- Magnitude
- 4.3light
moment magnitude (regional) (mwr) - Depth
- 10 km
- Status
- Reviewed
- Origin time
- 2026-10-16 23:57:50 UTC
- Local: 17 Oct 2026, 02:57:50 (Europe/Athens)
- Epicentre
- 38.299° N, 20.666° E
Circles show this event and others within 30 km from 7 days before to 30 days after. Lines: plate boundaries and GEM active faults. Open on the live map
Nearby places
| Place | Distance | Est. shaking |
|---|---|---|
| ArgostólionIonian Islands, Greece · pop. 9,820 | 20 km | IVLight |
| LixoúriIonian Islands, Greece · pop. 6,989 | 23 km | IVLight |
| AgrínioWest Greece, Greece · pop. 46,899 | 74 km | IIWeak |
| PátraWest Greece, Greece · pop. 168,034 | 94 km | IIWeak |
| PýrgosWest Greece, Greece · pop. 22,399 | 97 km | IIWeak |
| ÁrtaEpirus, Greece · pop. 21,895 | 100 km | IIWeak |
| AthensAttica, Greece · pop. 664,046 | 270 km | INot felt |
| ThessaloníkiCentral Macedonia, Greece · pop. 317,778 | 325 km | INot felt |
Shaking is an estimate from the intensity prediction equation of Allen, Wald & Worden (2012), not an observation. Local ground and buildings can change it by a level or more. Likely felt out to about 59 km.
Every agency's solution
Agencies locate earthquakes with their own stations and methods, so their numbers differ. We match reports of the same event by time, distance and magnitude and show them side by side. The headline uses USGS, which has been reviewed by an analyst.
How big was it?
Widely felt near the epicentre: rattling windows and objects. Significant damage is unlikely.
It released roughly the energy of 43 t of TNT. Magnitude is logarithmic: each whole step means about 32 times more energy and 10 times larger waves on a seismogram. Depth matters too: at 10 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.
M4.3 releases about 32× the energy of M3.3, and its waves are about 10× taller on a seismogram. Energy: 43 t of TNT vs 1.3 t of TNT.
Each square is the energy of one M3.3. Energy from log₁₀E = 1.5M + 4.8.
Aftershocks and nearby activity
2 later earthquakes within 30 km; the largest was M4.2 18 days ago. Aftershock rates usually fall off roughly in proportion to 1/time.
Mainshock M4.3
2 later earthquakes nearby. Aftershock rates typically fall off roughly as 1/time (Omori's law).
| Time after mainshock (hours) | Magnitude | Depth (km) |
|---|---|---|
| 204.52 | 4.2 | 10 |
| 213.23 | 4.2 | 51 |
Did you feel it?
Reports from people help show where shaking was strong. They are anonymous and shown here in aggregate.
Reports close 14 days after an earthquake.
Event id gfz2026uiai. First recorded here 17 Oct 2026, 00:10:04 UTC. Solutions: GFZ (geofon:gfz2026uiai); USGS (usgs:us6000u2ww). Cite as: SeismoAtlas, “M4.3 earthquake 20 km NE of Argostólion, Ionian Islands, Greece”, https://seismoatlas.com/earthquake/gfz2026uiai-m4-3-earthquake-20-km-ne-of-argostolion-ionian-islands-greece, data from USGS, GFZ.
JSON: /api/v1/events/gfz2026uiai. SeismoAtlas is not an official warning service.