Armenia–Georgia border
On the border of Armenia and Georgia, 80 km from the Deghdzavan station
- Date5 May 2025
- Main shockML 2.3 · 21:20:03 UTC
- Depth≈10 km
- Sequence≈1.6 → 2.3 → ≈1.4
Foreshock, main shock and aftershock, recorded by CHARNET
On the evening of 5 May 2025 the ground on the border of Armenia and Georgia did not shake once, but three times within two minutes. At 21:19:39 UTC a weak tremor was recorded. Twenty-four seconds later came a stronger one, magnitude 2.3. And then, a minute and a quarter later, a third, weaker again. None of them could be felt, but our stations heard every one.
Was it a chance cluster of small earthquakes? Or the textbook sequence that seismologists hope to catch: a foreshock that announces the event, the main shock, and an aftershock as the crust settles? Look at the record of the Deghdzavan station and decide for yourself.
Vertical component, 1–15 Hz, 160 seconds of record (21:19:29–21:22:09 UTC), shown 4× faster. Blue and gold — P- and S-waves of the foreshock; violet and red — the main shock; green — the aftershock. Times are UTC arrivals of the P-waves. Main-shock parameters: CHARNET bulletin (HYPO81); magnitudes of the foreshock and aftershock are estimated from their amplitudes.
- 21:19:39A weak foreshock, ML ≈1.6. Its waves reach Deghdzavan, 80 km away, after 14 seconds
- +24 sThe main shock, ML 2.3, from the same spot: about five times stronger on the record
- +72 sAn aftershock, ML ≈1.4. The crust settles
- 9.5 sFor all three events the S-wave follows the P-wave by the same 9.5 seconds — they came from one and the same source
Main shock: CHARNET bulletin, 41.17° N, 43.96° E, ML 2.3, depth ≈10 km · Records: CHARNET, IGES
Small earthquakes like these happen every week and are usually forgotten. But they are the material from which forecasts are made: if we learn to recognise a foreshock while it is happening, one day it may give a few precious seconds or minutes of warning before a stronger shock. That is why the institute records and studies even the weakest tremors.