Before 1976,
Friuli had already been struck by numerous devastating earthquakes. At the end
of the 19th century, the geologist Annibale Tommasi recorded 190 such events,
many of which were minor phenomena or part of seismic swarms. Of these, 126
were in fact classified as local events. Today, the most up-to-date databases,
such as the continuously updated Parametric Catalogue of Italian Earthquakes
curated by the National Institute of Geophysics and Volcanology (Istituto
Nazionale di Geofisica e Vulcanologia - INGV), record hundreds of events.
The first
earthquake for which there is a documented account in Friuli struck Aquileia
around the year 1000. In 1853, the engineer Gaetano Ferrante provided
information about it in relation to the damage suffered by the Basilica of
Santa Maria Assunta in 998 as a result of «an earthquake that shook and
levelled buildings and entire cities». However, Ferrante did not clarify
whether he was referring to the same «great and dreadful earthquake» that
impacted Verona and subsequently the lagoon area of Friuli in 1001. The first
earthquake of significant severity in the medieval period was certainly that of
1117, or 1116 according to different sources. In his book, Annali d’Italia
(Annals of Italy), Ludovico Antonio Muratori states that the earthquake of
1117 struck the German lands «and particularly Italy», a view also held by the
abbot Gian Francesco Palladio degli Olivi in his work Historie della
Provincia del Friuli (Histories of the Province of Friuli). Muratori wrote
that the tremors continued for forty days, while Palladio degli Olivi described
the destruction of the defensive towers of the monastery and the basilica of
Sesto al Reghena.
At midday on
Christmas Day 1222, a «terrible earthquake», with an estimated moment magnitude
of 5.68 (Mw 5.68), rocked Lombardy, Liguria, Emilia, Veneto, and Friuli.
Brescia suffered the worst of the devastation, with Cividale del Friuli also
sustaining significant damage. In the aftermath, the ducal city witnessed the
relocation of the Patriarchate to Udine, which had experienced less intense
seismic activity. This accelerated the development of the settlement known as «vile
di Udin» into a city. In the same century, on April 23 1279, a «very
strong» earthquake also triggered the collapse of several castles across
Friuli.
Just 22 years
later, on June 11 1301, another powerful earthquake «caused the collapse of
many buildings in various parts of the territory». Francesco di Manzano added
that this was followed by «a terrible storm with hail as big as hen’s eggs,
particularly in the area surrounding Cividale. As a result, this region was
plagued by misery for several years».
One of the
most disastrous earthquakes in the history of Friuli and indeed Italy occurred
on January 25 1348 (Mw 6.63). This tragedy befell the region in the same year
that the Black Death ravaged Italy and Europe. It appears to have been the
strongest earthquake north of the Po River for which reliable historical
records exist. With its epicentre in the Julian Alps, the earthquake was felt
as far away as Veneto, Lombardy, Emilia, Austria, Bavaria, and Dalmatia. It
caused thousands of deaths and enormous damage. In Udine, it destroyed part of
the Castle and the patriarchal palace. In Aquileia, a section of the basilica
collapsed. Castles and palaces in Ragogna, Flagogna, San Daniele, Tolmezzo and
Sacile were also destroyed. Gemona and Venzone were severely affected by the
earthquake, as well. The most severe damage was sustained by the lands of the
Archduke. The southern part of the Dobratsch massif collapsed, with only wooden
houses without foundations remaining intact in Villach. From 1348 to 1511,
Tommasi recorded nine seismic events, most of which were relatively confined to
the local area. Although they «ruined buildings», they did not cause any
widespread destruction.
On March 26
1511, a bloody revolt broke out between pro-Venetian and pro-Imperial factions
in Udine and spread to much of Friuli. This revolt had been preceded by the
uprising of the “Zobia Grassa” on Shrove Thursday on February 26.
Another very strong earthquake (Mw 6.32) subsequently shook a wide mountainous
area on the border between present-day Italy and Slovenia. The tremors
continued until August and were felt throughout Veneto, particularly in Venice,
and in Romagna. According to chronicles, it was «the most frightening that had
ever taken place in Udine and Friuli». The damage in Udine was extensive. Much
of the castle and its defensive walls collapsed, as did the loggia of the
Church of San Giovanni, the bell tower and the Church of Santa Maria, along
with many houses. The cathedral also sustained damage. Palladio degli Olivi
reported that «from its summit, a pinnacle fell, smashing the roof and
uncovering the tombs of some of those killed in the riots of Shrove Tuesday».
In Cividale, the earthquake destroyed 28 houses, the bell tower and another
tower attached to the main monastery. Serious devastation was also unleashed in
Osoppo, Sacile, Pinzano, Faedis, Tarcento, Moruzzo, Colloredo, Fagagna,
Villalta and Artegna, while Pordenone escaped relatively unscathed.
After 1511,
almost every year in the 16th century was marked by an earthquake. Tommasi
recorded over 50 events, not all of which were violent, and none of which were
as disastrous as the earthquake of 1511. In contrast, the chronicles of the
17th century report rare events. The 18th century was also afflicted by
numerous disastrous earthquakes, and records of these events have survived
thanks to the increased attention of scholars and chroniclers.
On July 28
1700, a shock of strong intensity (Mw 5.70) struck Enemonzo, in Carnia. On that
occasion, «the ground shook, houses collapsed, the walls of the church cracked,
and six people died». After the events of 1746, 1750, and 1776 in Tramonti and
Meduno (Mw 5.86), the shock of October 20 1788, in Tolmezzo (Mw 5.19) caused
the collapse of the cathedral and about forty houses, burying several people.
The earthquake of January 26 1790, with epicentre in Sutrio, ruined many
buildings, including the Linussio linen factory of Tolmezzo, one of the largest
textile industries of the time in Italy, which never recovered from the severe
damage.
From the 19th
century onwards, the annual recording of significant seismic events or
individual low-intensity shocks became increasingly common, thanks to the
greater availability of information and the growing interest of scholars and
newspapers in earthquakes, the origins of which science was still struggling to
explain. A total of 115 reports were recorded in the 19th century alone,
confirming that Friuli is particularly susceptible to this type of event.
Regarding the
earthquake in the territory surrounding Pordenone on October 25 1812 (Mw 5.62),
the Friulian Girolamo Venerio noted in his work Osservazioni meteorologiche (Meteorological Observations) that it
«was strong in Belluno, Treviso, Vicenza and the Garda area, as well as in
Trentino and Bavaria». He recorded a further 23 light shocks up to January
1842, to which the 27 shocks reported by the periodical of Udine, «L'Alchimista Friulano», between
February and March 1853 also have to be included.
The earthquake
that struck on June 29 1873 was one of the strongest and is impossible to
overlook. This event hit Mortegliano and Santa Margherita del Gruagno, but it
was described as «the most disastrous» in Belluno, where the municipal council
«hurried to send ice», according to the «Giornale
di Udine» newspaper. The epicentre was located in the Cansiglio
and Alpago areas, and the earthquake measured an exceptional, Mw 6.29 in intensity.
The earth
shook again in Friuli in 1906, 1908, 1910, 1911, 1920, 1924, and 1926, before
the very violent earthquake (Mw 5.99) that, in Carnia, with its epicentre on
Mount Bottai, destroyed the municipalities of Verzegnis and Cavazzo Carnico on
March 27 1928, and caused serious damage from Paluzza to Clauzetto and from
Tramonti to Venzone. Even stronger was the event of October 18 1936 (Mw 6.19),
with an epicentre between Alpago and Cansiglio. It affected the area of Sacile,
Polcenigo, and Caneva, was felt as far as Trieste, and caused casualties and
extensive damage, particularly to the cathedral of Sacile. This earthquake is
not well-documented. The Fascist regime preferred not to draw attention to a
tragic event in the year of the proclamation of the empire and the war in
Spain. No public subscription was launched, and even the local newspapers
relegated the event to the inner pages with brief reports.
During the
second post-war period, before the earthquake of 1976, other seismic events
affected Carnia. Following a series of minor tremors between 1954 and 1957, the
But River Valley was hit by an earthquake on April 26 1959 (Mw 5.25). Although
there were no casualties, the houses in Zuglio were seriously damaged.