Medieval buildings affected by the 1976 Friuli earthquake

Earthquakes produce widespread damage to buildings, infrastructures and landscape.

Historical buildings are significantly exposed to seismic risk,  and in many seismogenic areas their preservation is often threatened by seismic hazard.

Many recent earthquakes in Italy (Friuli 1976, Umbria 1997, Abruzzo 2009, Emilia 2012) affected several medieval buildings, such as the Basilica of San Francesco di Assisi (Umbria 1997), many medieval churches in L’Aquila (Abruzzo 2009), and the Castle of Rocca Estense, San Felice sul Panaro (Emilia 2012).

Sometimes, these effects are still recognisable, mainly when restoration works intentionally avoided the removal or the obliteration of the affected structures. This is the case of some medieval buildings in Venzone and Gemona del Friuli, two towns situated very close to the 1976 Friuli earthquake epicentre (M 6.5 ).

The Dome of Venzone, after the M 6.5 mainshock  (May 1976)
The Dome of Venzone, after the M 6.5 mainshock (May 6, 1976), from “Venzone. La ricostruzione del centro storico”, Villorba (2006), p. 60

Here, the 14th century Dome of S. Andrea in Venzone (built between AD 1308-1338)  and the Dome of Santa Maria Assunta in Gemona (AD 1290-1337) still present evident EAE (Earthquake Archaeological Effects) and therefore we can look at those churches as clear examples of seismic-affected medieval buildings, although the seismic event occurred less than 40 years ago.

The Dome of Venzone after two strong aftershocks (September 1976).
The Dome of Venzone after two strong aftershocks (September 11 and 15, 1976). From “Venzone. La ricostruzione del centro storico”, Villorba (2006), p. 62

They can be considered as exceptional ‘stone catalogues’ of EAE, intrinsically useful for the comprehension of the response of medieval masonry buildings to seismic loads but also for the comparative identification of EAE in those medieval buildings for which historical information is lacking or completely absent.

The following pictures show some of the most interesting EAE still recognisable in those buildings.

Venzone. Dome of Saint Andrea.
Venzone. The Dome of Saint Andrea today.
DSC_0892
Venzone, Dome of Saint Andrea. Dropped keystone in a gothic door arch. Apsidal area.
Venzone, Dome of Saint Andrea. Displaced mansory blocks in an internal pilaster.
Venzone, Dome of Saint Andrea. Displaced mansory blocks in an internal pilaster.
Venzone, Dome of Saint Andrea. Displaced and rotated mansard blocks in the apsidal buttresses.
Venzone, Dome of Saint Andrea. Displaced and rotated masonry blocks in the apsidal buttresses.
Venzone, Dome of Saint Andrea. Tilted base wall of the facade. It's been later superimposed by restoration work.
Venzone, Dome of Saint Andrea. Tilted base wall of the façade. It’s been later superimposed by the reconstructed façade.
Dome of Santa Maria Assunta in Gemona del Friuli.
Dome of Santa Maria Assunta in Gemona del Friuli. Façade.
DSC_0130
Dome of Santa Maria Assunta in Gemona del Friuli. Displaced mansory blocks in an internal column. Note the deformation of the colonnade eastward.
Dome of Santa Maria Assunta in Gemona del Friuli. Deformed colonnade.
Dome of Santa Maria Assunta in Gemona del Friuli. Deformed colonnade.

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