M4.5 Earthquake Strikes 2 km NNW of Ástros, Greece

A magnitude 4.5 earthquake struck Greece at 23:55 UTC on Friday, August 28, 2026, according to data from the United States Geological Survey (USGS). The earthquake's epicentre was located 2 km NNW of Ástros, Greece, at a focal depth of 89.6 km.

Event Details

With a focal depth of 89.6 km, this earthquake falls into the intermediate depth category (70–300 km). At this depth, seismic waves travel further before reaching the surface, spreading energy over a wider area. While shaking intensity at the epicentre is somewhat reduced compared to a shallow event of equal magnitude, an intermediate earthquake can be felt across a much larger region.

The earthquake registered a magnitude of 4.5 on the moment magnitude scale — the standard measurement used by seismologists worldwide. At this magnitude, the shaking is felt strongly by everyone; minor to moderate damage possible in vulnerable buildings.

Where Did This Earthquake Occur?

Greece and the broader Aegean region are among the most seismically active areas in Europe, positioned along the Hellenic Arc where the African Plate subducts beneath the Eurasian Plate.

Greece accounts for approximately 50% of all seismic energy released in Europe. The Ionian Islands, Crete, and the North Aegean are historically the most active zones, though significant earthquakes can and do occur across the entire country.

What Does Magnitude 4.5 Mean?

Moderate earthquakes are felt by virtually everyone near the epicentre. Strong shaking lasting 10–30 seconds can topple unsecured items, crack plaster, and cause poorly anchored objects to fall. Aftershocks are common following moderate events.

Significant damage can occur to vulnerable structures — particularly unreinforced masonry, old adobe buildings, and poorly maintained older construction. Well-engineered modern buildings are designed to withstand this level of shaking with minimal structural impact, though contents may shift and non-structural elements (ceilings, partitions) can be damaged.

A magnitude 4.5 earthquake releases approximately roughly 500 tonnes of TNT of energy. For comparison, this exceeds the energy released by most conventional explosive events and is sufficient to shift tectonic stress in measurable ways across a wide region.

Safety Guidance

Keep an earthquake emergency kit accessible at home. It should include at least 72 hours of water (4 litres per person per day), non-perishable food, a first aid kit, torch, battery-powered radio, copies of important documents, and essential medications. Reviewing and restocking this kit annually is strongly recommended.

After an earthquake, expect aftershocks. Check yourself and others for injuries. Inspect your surroundings for hazards before moving — broken glass, gas leaks (smell), downed power lines, and structural damage. If you suspect a gas leak, open windows and evacuate without using electrical switches or open flames.

The Greek Earthquake Planning and Protection Organisation (OASP/EPPO) provides guidance and resources for residents. Standard Drop, Cover, Hold On procedures apply, and coastal residents should move inland immediately after strong shaking.

Monitoring and Aftershocks

Seismologists are continuing to monitor the region for aftershocks, which are common following earthquakes of this magnitude. Aftershocks can occur minutes, hours, or even days after the main event and are sometimes strong enough to cause additional damage to already-weakened structures. Residents in the area are advised to remain cautious and follow guidance from local authorities.

Real-time seismic data is being collected by the USGS and contributing regional networks. Updated information will be published as it becomes available. You can track this and all other global seismic activity in real time on our live earthquake map.

Building Codes and Earthquake Resilience

One of the most effective tools against earthquake damage is modern building codes that specify how structures must be designed and constructed to withstand seismic forces. Countries with active fault zones have developed increasingly sophisticated seismic design standards over the past 50 years. However, the gap between modern code-compliant buildings and older existing structures remains a critical challenge in earthquake risk reduction worldwide. Building retrofit programmes and public awareness campaigns are key components of any national earthquake preparedness strategy.