An earthquake of magnitude 4.2 occurred early on Saturday morning, October 17, 2026, at 2:57 am local time near Argostoli, Kefallonia, Ionian Islands, Greece, as reported by the European-Mediterranean Seismological Centre (EMSC).According to preliminary data, the quake was located at a very shallow depth of 5. km. Shallow earthquakes are felt more strongly than deeper ones because they are closer to the surface. The exact magnitude, epicenter, and depth of the quake might be revised within the next few hours or minutes as seismologists review the data and refine their calculations, or as other agencies issue their reports.Our monitoring service identified a second report from the German Research Centre for Geosciences (GFZ), which listed the quake at magnitude 4.3. Other agencies reporting the same quake include the National Observatory of Athens (NOA) at magnitude 4.2, the Seismological Laboratory of the University of Athens (UOA) at magnitude 4.2, the Aristotle University of Thessaloniki Geophysical Lab. (AUTH) at magnitude 4.2, and the citizen-seismograph network of RaspberryShake at magnitude 4.3.Based on the preliminary seismic data, the quake was probably felt by many people in the area of the epicenter. It should not have caused significant damage, other than objects falling from shelves, broken windows, etc.Moderate shaking probably occurred in Sami (pop. 1,300), located 3 km from the epicenter.Weak shaking might have been felt in Ithaki (pop. 1,800), located 11 km from the epicenter; Valsamata (pop. 1000), 13 km away; Faraklata (pop. 1,100), 15 km away; Argostoli (pop. 9,800), 19 km away; Lixouri (pop. 3,800), 22 km away; Agrinio (pop. 46,900), 75 km away; and Preveza (pop. 17,300), 77 km away.Other towns or cities near the epicenter where the quake might have been felt as very weak shaking include Amaliada (pop. 16,800), located 79 km from the epicenter.Earthquake data: Date & time: Oct 17, 2026 02:57 am (GMT +3) local time (16 Oct 2026 23:57 GMT)Magnitude: 4.2Hypocenter depth: 5.00 kmEpicenter coordinates: 38.27°N / 20.67°E (Ionian Islands, Greece)Primary data source: EMSC