The 1169 Sicily earthquake occurred on 4 February 1169 at 08:00 local time on the eve of the feast of

St. Agatha Agatha of Sicily () is a Christian saint. Her feast is on 5 February. Agatha was born in Catania, part of the Roman Province of Sicily, and was martyred . She is one of several virgin martyrs who are commemorated by name in the Canon of the Mas ...

Sicily (man) it, Siciliana (woman) , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = Ethnicity , demographics1_footnotes = , demographi ...

(in southern

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

). It had an estimated magnitude of between 6.4 and 7.3 and an estimated maximum perceived intensity of X (''Extreme'') on the

Mercalli intensity scale The Modified Mercalli intensity scale (MM, MMI, or MCS), developed from Giuseppe Mercalli's Mercalli intensity scale of 1902, is a seismic intensity scale used for measuring the intensity of shaking produced by an earthquake. It measures the ef ...

. The cities of

Catania Catania (, , Sicilian and ) is the second largest municipality in Sicily, after Palermo. Despite its reputation as the second city of the island, Catania is the largest Sicilian conurbation, among the largest in Italy, as evidenced also b ...

Lentini Lentini ( scn, Lintini, historically Liuntini; la, Leontīnī; grc, Λεοντῖνοι) is a town and in the Province of Syracuse, South East of Sicily (Southern Italy). History The city was founded by colonists from Naxos as Leontini in 72 ...

and

Modica Modica (; scn, Muòrica) is a city and '' comune'' of 54,456 inhabitants in the Province of Ragusa, Sicily, southern Italy. The city is situated in the Hyblaean Mountains. Modica has neolithic origins and it represents the historical capit ...

were severely damaged, and the earthquake also triggered a

tsunami A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater exp ...

. Overall, the earthquake is estimated to have caused the deaths of at least 15,000 people.

Tectonic setting

Sicily lies on part of the complex

convergent boundary A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a p ...

where the African Plate is subducting beneath the

Eurasian Plate The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent an ...

. This subduction zone is responsible for the formation of the

stratovolcano A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and peri ...

Mount Etna Mount Etna, or simply Etna ( it, Etna or ; scn, Muncibbeḍḍu or ; la, Aetna; grc, Αἴτνα and ), is an active stratovolcano on the east coast of Sicily, Italy, in the Metropolitan City of Catania, between the cities of Messina ...

. Most of the damaging earthquakes occur on the Siculo-Calabrian rift zone, a zone of extensional faulting which runs for about , forming three main segments through Calabria, along the east coast of Sicily and immediately offshore, and finally forming the southeastern margin of the

Hyblean Plateau Hybla may refer to: __NOTOC__ Places Sicily *Hybla Gereatis or Hybla Galeatis, possibly modern Paternò *Hybla Heraea, historic quarter (Ibla) of modern Ragusa *Hybla Major, perhaps identical with Megara Hyblaea or with Hybla Gereatis * Hybla Mino ...

, a carbonate platform in southeastern Sicily. Faults in the Calabrian segment were responsible for the 1783 Calabrian earthquakes sequence. In the southern part of the eastern coast of Sicily, investigations have identified a series of active normal dip-slip faults, dipping to the east. Most of these lie offshore, and some control basins that contain large thicknesses of

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million year ...

sediments. The two largest faults, known as the western and eastern master faults, border

half-grabens A half-graben is a geological structure bounded by a fault along one side of its boundaries, unlike a full graben where a depressed block of land is bordered by parallel faults. Rift and fault structure A rift is a region where the lithosphere ...

, with fill of up to and respectively. Onshore, two ages of faulting have been recognised, an earlier phase trending NW-SE and a later phase trending SSW-NNE that clearly offsets the first group, including the Avola fault and the Rosolini-Ispica fault system.

Earthquake

The location of the earthquake's epicentre is quite uncertain, with different seismologists giving locations offshore and onshore; there is similar uncertainty regarding the 1693 Sicily earthquake. The damaged area is similar to that for the 1693 earthquake, suggesting that both the location and magnitude were similar. Intensities of X (''Extreme'') have been estimated for Catania,

and

, IX (''Violent'') at

Syracuse Syracuse may refer to: Places Italy * Syracuse, Sicily, or spelled as ''Siracusa'' * Province of Syracuse United States *Syracuse, New York **East Syracuse, New York ** North Syracuse, New York * Syracuse, Indiana *Syracuse, Kansas *Syracuse, M ...

and

Piazza Armerina Piazza Armerina ( Gallo-Italic of Sicily: ''Ciazza''; Sicilian: ''Chiazza'') is a '' comune'' in the province of Enna of the autonomous island region of Sicily, southern Italy. History The city of Piazza (as it was called before 1862) develop ...

and VIII (''Severe'') at

Santi Pietro e Paolo Santi Pietro e Paolo may refer to the following churches in Italy: * Santi Pietro e Paolo, Acireale * Santi Pietro e Paolo, Arese * Santi Pietro e Paolo, Brebbia * Santi Pietro e Paolo, Buonconvento * Santi Pietro e Paolo, Castelnuovo di Garfagn ...

and

Messina Messina (, also , ) is a harbour city and the capital of the Italian Metropolitan City of Messina. It is the third largest city on the island of Sicily, and the 13th largest city in Italy, with a population of more than 219,000 inhabitants in t ...

. The earthquake was also felt in Calabria with a maximum intensity of VI (''Strong'') in

Reggio Calabria Reggio di Calabria ( scn, label= Southern Calabrian, Riggiu; el, label= Calabrian Greek, Ρήγι, Rìji), usually referred to as Reggio Calabria, or simply Reggio by its inhabitants, is the largest city in Calabria. It has an estimated popul ...

. The magnitude of the earthquake has been estimated from intensity information and these estimates vary from 6.4 on the M_e (Energy magnitude scale) to 7.3 on the surface wave magnitude scale.

Tsunami

The tsunami affected most of the Ionian coast of Sicily and caused inundation from Messina in the north to the mouth of the Simeto River in the south.

Tsunami deposit A tsunami deposit (the term tsunamiite is also sometimes used) is a sedimentary unit deposited as the result of a tsunami. Such deposits may be left onshore during the inundation phase or offshore during the 'backwash' phase. Such deposits are u ...

s correlated with this earthquake have been found both onshore and offshore. The tsunami is also thought to be responsible for moving several large boulders from the middle of the sublittoral zone onto the coast between Augusta and Syracuse.

Eruption of Etna

Some accounts of this earthquake refer to a major eruption from Etna at the time of the earthquake, blaming most of the deaths in Catania and the tsunami on the eruption. However, most later workers believe that the tsunami was triggered by the earthquake and that the only effect on Etna was the collapse of part of the cone above

Taormina Taormina ( , , also , ; scn, Taurmina) is a ''comune'' (municipality) in the Metropolitan City of Messina, on the east coast of the island of Sicily, Italy. Taormina has been a tourist destination since the 19th century. Its beaches on ...

, with no significant eruption. As with the 1693 earthquake the 1169 event seems to have followed after a major period of eruptive activity. Calculations have shown that a major eruption may significantly increase the stress on the normal faults to the south-east of the volcano.

Damage

Catania was almost completely destroyed. Catania Cathedral collapsed, killing the Bishop John of Ajello, 44 of the Benedictine monks, and many others who were crowded into the building for the feast of St. Agatha. Lentini, Modica, Aci Castello, Sortino and Syracuse were also severely damaged. In a contemporary account, Hugo Falcandus described the effects on the Arethusa spring in Syracuse, which increased its rate of flow greatly and became salty. Near

Casale Saraceno Casale may refer to: *''Casalis'', medieval Latin for a group of houses in the countryside Places in Italy Communes * Casal di Principe in the province of Caserta, Campania * Casal Velino in the province of Salerno, Campania * Casalattico, wh ...

the flow of another spring, known as Tais, stopped after the earthquake. Two hours later it returned with much greater force than before and had the colour of blood. Estimates of the death toll in the earthquake vary, with 15,000 being often quoted, sometimes for the overall total and sometimes just for Catania. A few sources give the higher estimate of 25,000.

Aftermath

In the chaos that followed the earthquake, there was concern that exiles like Tancred of Lecce and Robert of Loritello would take part in a Byzantine invasion of the island. However, these disaffected exiles were soon allowed to return and there was no invasion, nor the rebellion that it might have triggered.

Peter of Blois Peter of Blois ( la, Petrus Blesensis; French: ''Pierre de Blois''; ) was a French cleric, theologian, poet and diplomat. He is particularly noted for his corpus of Latin letters. Early life and education Peter of Blois was born about 1130. Ear ...

saw the earthquake as God's punishment on the Sicilians for the exile of

Stephen du Perche Stephen du Perche (1137 or 1138 – 1169) was the chancellor of the Kingdom of Sicily (1166–68) and Archbishop of Palermo (1167–68) during the early regency of his cousin, the queen dowager Margaret of Navarre (1166–71). Stephen is desc ...

and the appointment of Bishop

John of Ajello John of AjelloAlso spelled "Agello", in Italian ''Giovanni d'Aiello'' or ''Giovanni da Salerno''. His family was from Salerno, but the name "Ajello", which comes from Aiello del Sabato, is applied retrospectively. John's nephew Richard became the f ...

, through bribery, to the see of Catania, replacing his brother William of Blois in the post.

References

{{authority control 1169 Sicily Sicily earthquake Sicily earthquake 12th century in the Kingdom of Sicily Catania Medieval tsunamis