Earthquake Risk in the Algarve

The 1755 earthquake

On 1 November 1755, a magnitude 8.5+ earthquake struck offshore, followed by a tsunami. It destroyed much of Lisbon and devastated the Algarve coast. Lagos, Albufeira and Faro suffered extensive damage. This remains one of the most powerful earthquakes in European history.

Modern seismic risk

The Algarve sits near the Azores-Gibraltar fault zone. All 16 municipalities are classified as Seismic Zone 1.2 (Type 1, Atlantic offshore earthquakes) under Eurocode 8, with a peak ground acceleration (PGA) of 0.20g. This is a moderate to high seismic risk by European standards.

What this means for buildings

All new construction in the Algarve must comply with Eurocode 8 seismic design standards. This includes specific foundation requirements, structural reinforcement and design considerations for earthquake loading.

Older buildings (pre-1983) were built before modern seismic codes and may not meet current standards. If buying an older property, consider a structural survey that specifically assesses seismic resilience.

Tsunami risk

The Algarve's south coast faces a low-probability but high-consequence tsunami risk from Atlantic seismic events. IPMA (Portuguese meteorological institute) operates a tsunami warning system. Properties at very low elevation near the coast carry higher exposure.

Insurance

Standard Portuguese property insurance covers earthquake damage. Premiums in the Algarve are marginally higher than northern Portugal but not prohibitive. Buildings insurance is required by mortgage lenders and recommended for all owners.

Should I be concerned?

The risk is real but managed. Portugal has modern building codes, warning systems and emergency planning. The Algarve's seismic risk is comparable to parts of Italy, Greece or Turkey. It should inform your building choice (prefer modern construction to unreinforced old buildings) but should not deter purchase.