Which seismic zone is a house in

In Italy the seismic zone is set per municipality: every house in the same municipality has the same one, from 1 (the most hazardous) to 4. You can find it on your municipality's page on this site or in the Civil Protection list. To know how hard the ground can shake right under the house, and how well the building would hold up, the zone alone is not enough.

The zone covers the whole municipality, the exact point does not

The seismic zone (zona sismica) comes from the national list kept by the Civil Protection Department (Dipartimento della Protezione Civile), which gathers the decisions of the Regions (the latest version is updated to 31 May 2025). Some Regions split the zones into sub-zones, for example 2A and 2B in Lazio or 3S in Piedmont. What changes from one zone to the next is explained in Seismic zones 1, 2, 3 and 4: what they mean for buyers.

Within the same municipality, though, two houses can face very different shaking. Two things matter.

The first is the hazard at the point. The National Institute of Geophysics and Volcanology (INGV) has calculated, for a dense grid of points across Italy, the ground acceleration to expect in an earthquake, the PGA: the value with a 10% probability of being exceeded in 50 years, measured on rock. This is the MPS04 map, the same one the building code starts from when a new building is designed. In a large municipality, or one that runs from the plain up into the hills, the value changes from one district to another.

The second is the ground. On rock the shaking arrives as it is; on sand, clay or made ground it can arrive stronger. This is measured by seismic microzonation studies, which municipalities carry out, the Civil Protection Department collects and the CNR (the national research council) publishes on the WebMS portal. The studies come in three levels: the first divides the area by type of ground, the second and third say how much the ground amplifies the shaking. In Rimini, for example, the factors of the studied zones range from about 1.25 to 1.55, so the shaking arrives between a quarter and just over half as strong again as on rock. The same studies flag places where the ground may slide or liquefy, and active faults. Not every municipality has a study, and where there is none you cannot say the ground is good: nobody has measured it.

The zone does not tell you whether the building is safe

A well-designed house in zone 1 can stand up to an earthquake better than an old house in zone 3 that was never strengthened. To tell which side the building you are looking at falls on, what matters first is when it was designed, because the rules have changed many times:

• law 64 of 1974 set the first modern earthquake rules, but they only applied in the municipalities classified at the time, far fewer than today;
• government order (ordinanza) 3274 of 2003 reclassified the whole of Italy and brought thousands of municipalities into a seismic zone for the first time;
• the 2008 building code became compulsory for designs from 1 July 2009, after the L'Aquila earthquake, and today the 2018 code applies (Norme tecniche per le costruzioni, NTC 2018).

A 1970s reinforced concrete block of flats in a municipality classified only in 2003 was therefore designed without earthquakes in mind. The same goes for many masonry houses in historic centres, although these depend a lot on how the structure has been kept and altered: a load-bearing wall removed to open up the kitchen counts for more than age.

The documents to ask for are the structural testing certificate (collaudo), any certificate of structural soundness (certificato di idoneità statica), the certificate of fitness for use (agibilità) and the permits for any structural work done after construction. An engineer or a geometra (building surveyor) can estimate the building's seismic risk class, from A+ to G, following the guidelines of ministerial decree 58 of 2017.

If the building has been strengthened recently, ask whether the work was done with the sismabonus, the tax deduction for earthquake-proofing buildings in zones 1, 2 and 3: if the paperwork is closed, you also have a written record of what was done. Rates and deadlines change with each budget law, and the current ones are on the Revenue Agency (Agenzia delle Entrate) page, in Italian.

What the report shows

Type the address: straight away, and free, you see the liveability index of the area. In the full report the earthquake section has four parts.

First, the municipality's seismic zone, with the sub-zone where the Region uses one and the date of the list. Then the ground acceleration expected at the address, worked out from the four nearest INGV grid points, with its uncertainty range. Where the municipality has a microzonation study, a separate block says how the ground under the house shakes: how much it amplifies the shaking and whether the study flags landslides, liquefaction or faults at the point or nearby. Finally, what earthquakes cost on average each year, in euros, for a 100 square metre home: the average annual damage, to set against the premium of a natural catastrophe insurance policy (how we work it out).

Alongside these you find the age of the buildings in the area from the Istat census, and the questions to put to the seller and the building manager about the year of construction, strengthening work and structural documents. The report looks at the plot and the building, not at a single flat, and it does not replace a check by an engineer or surveyor: sources and limits are in Earthquakes.

Find your municipality

Every municipality has a page with its seismic zone and expected ground acceleration, as well as residents and public transport: you will find it in the list of municipalities, by region and province. For the exact point of a house you need the address.

Frequently asked questions

How do I find the seismic zone of my municipality?

Look it up in the list of municipalities on this site, or download the official list from the Civil Protection page on seismic classification (in Italian). The zone is the same for every house in the municipality.

Can a municipality's seismic zone change?

Yes. The Regions update the classification with their own decisions and the Civil Protection Department keeps the national list up to date. A municipality can change zone after a house has been built, which is why it matters to know which rules the building was designed under.

Is a house in zone 4 safe from earthquakes?

Strong earthquakes are rare in zone 4, but the condition of the structure still matters: cracks, subsidence and altered load-bearing walls are questions worth asking there too.

What is seismic microzonation and do I need it to buy a house?

It is the municipality's study of how the ground responds, zone by zone. It is not a required document for completion, but it tells you whether the shaking under the house arrives stronger than on rock and whether the ground is unstable.