Earthquake faults and property in Greece: what public maps show

• Active faults: lines where researchers have mapped breaks in the earth's crust that are considered active. The NOAFAULTs database notes that such faults can cause surface ruptures or strong ground shaking.
• Seismic hazard zones: the official map that engineers use to design buildings under the Greek seismic code. It sets the design ground shaking for each area, so every location in Greece falls in a zone.
• The building: how it was designed and built, what has changed since, and the state it is in today. This is what a civil engineer looks at, and no public map can answer it.

A fault map is about the ground. Your purchase is about a building on that ground. Keep the two apart when you read any report, ours included.

NOAFAULTs is a public database of active faults in Greece, maintained at the National Observatory of Athens. It was built to support earthquake monitoring, by collecting fault maps published in peer-reviewed journals since 1972. It records each fault's geometry and, where known, its type of movement, slip rate and links to past earthquakes. It is published openly under a CC BY 4.0 licence.

• Version 5.0 (June 2023) holds 2,916 active faults drawn from 140 scientific papers. Most (91%) are normal faults, where the crust is being pulled apart.
• Version 7.0 (August 2025) holds 3,441 faults drawn from 158 papers.
• Fault traces were digitised at the scale of the original published maps, so a line is only as precise as the map it came from.

The growth between versions is a reminder that the catalogue reflects what has been studied and published. A place with no mapped fault nearby may simply not have been studied in detail.

Buildings in Greece are designed to the Greek Seismic Code (ΕΑΚ 2000), approved in December 1999, and to Eurocode 8. Its seismic hazard map was revised by ministerial decision in August 2003 and divides the country into three zones. The zone, not the distance to a mapped fault, is what sets the earthquake load in a structural design.

That map is now more than 20 years old. In 2023 the Earthquake Planning and Protection Organisation (ΟΑΣΠ) commissioned a roadmap for updating it. In April 2026 a team at the Aristotle University of Thessaloniki submitted a proposed new map to ΟΑΣΠ and the Hellenic Standards Organisation (ΕΛΟΤ). It has five zones instead of three and is aligned with the revised Eurocode 8. Press reports at the time described it as a proposal, not yet in force.

• When it was designed: buildings designed before ΕΑΚ 2000 followed older rules. A civil engineer can tell you what that means for the specific structure.
• How it was built and changed: added floors, removed walls or columns, and unpermitted extensions can change how a building behaves in an earthquake. Our guide to unauthorised buildings covers how to check the permits.
• Ground floor layout: the seismic code itself sets extra requirements for some buildings with an open ground floor (pilotis) or shopfronts and no shear walls.
• Condition and ground: cracks, corrosion, moisture, slopes and fill are for an on-site inspection, not a map.

• A short distance is a reason to ask questions, not proof of danger.
• A long distance is not proof of safety. Every location is in an official seismic zone, and shaking does not stop at the line on a map.
• Line positions are approximate, and the catalogue may not include every active fault.
• The catalogue says nothing about soil, foundations or the building.