A magnitude M 6.2 earthquake (source: INGV) was recorded at 11:49 a.m. Italian time (09:49 UTC) on 23 April 2025 in the Sea of Marmara - in Turkey - about 20 km southeast of Marmara Ereglisi and about 50 km from the western outskirts of Istanbul.
The epicentre of the earthquake was located offshore and, based on the decision matrix used in the NEAMWTS area, the INGV-Tsunami Alert Centre issued an advisory message (orange) for a potential tsunami at the local level just 4 minutes after the event. In the following minutes, tide gauge data confirmed the tsunami, albeit very small (a few centimetres).
At 10:18 a.m. UTC, a tsunami ongoing message (confirmation) was sent following the analysis of the signals reported to the tide gauges in the area. Specifically, at the tide gauge of Ereglisi in Turkey, the closest to the earthquake epicentre: several anomalous oscillations of the sea were noted starting at around 10 a.m. UTC, with peak-to-peak amplitudes of around 10 cm.
UPDATE 13:57 UTC
Not observing further significant variations in the tide gauge signals, at 13:57 UTC an ENDING message of warning was issued.