The 1968 Belice earthquake sequence took place in

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

between 14 and 15 January. The largest shock measured 5.5 on the

moment magnitude scale The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 pa ...

, with five others of magnitude 5+. The maximum perceived intensity was X (''Extreme'') on the Mercalli intensity scale. The

earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fr ...

sequence, centred between the towns of

Gibellina Gibellina ( Sicilian: ''Jibbiddina'', Arabic: "little mount" - جبل صغير) is a small city and ''comune'' in the Province of Trapani, the mountains of central Sicily, Italy. It was destroyed by the 1968 Belice earthquake. The new city, G ...

, Salaparuta and Poggioreale, killed at least 231 people, possibly more than 400, with between 632 and about 1,000 injured and left 100,000 homeless. It is known in Italy as Terremoto del Belice.

Tectonic setting

Sicily lies on the complex

convergent plate 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 ...

between the African Plate and 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 ...

. The geology of the western part of the island is dominated by the Gela Nappe, a thin-skinned fold and thrust belt. The Gela Nappe consists of

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Quaternary age sedimentary rocks deposited in the earlier foredeep, thrust up onto the thick carbonate sequence of the Pelagian-Hyblean Platform of the African Plate.

Earthquake

There was a sequence of six M 5+ earthquakes, making this western Sicily's largest historical seismic event, beginning with a M 5.2 shock at 12:28 on the 14 January, followed by a M 5.1 event at 13:15 on the same day and a M 5.2 event at 01:33 on 15 January, the mainshock at 02:01, and two M 5.2 events at 16:42 on 16 January and at 09:56 on 25 January. The greatest perceived intensity on the Mercalli scale was X (''Extreme'') at Gibellina, Montevago and Salaparuta. Intensities at Poggioreale, Santa Margherita di Belice, Santa Ninfa, Partanna and Salemi reached IX (''Violent'') on the scale. Poggioreale ruderi2

The

focal mechanism The focal mechanism of an earthquake describes the deformation in the source region that generates the seismic waves. In the case of a fault-related event it refers to the orientation of the fault plane that slipped and the slip vector and ...

s of the mainshock and the two magnitude 5+ aftershocks are consistent with thrusting on faults trending west–east, although an alternative solution has been proposed for the mainshock of right lateral

transpression In geology, transpression is a type of strike-slip deformation that deviates from simple shear because of a simultaneous component of shortening perpendicular to the fault plane. This movement ends up resulting in oblique shear. It is generally ve ...

on a NNW-SSE trending fault.

Damage

The main area of damage was centred on the valley of the Belice, with worst affected towns being

Santa Ninfa Santa Ninfa is a town and '' comune'' in the province of Trapani, Sicily, southern Italy. History Santa Ninfa was founded in 1605 by Luigi Arias Giardina who, with approval of King Philip III of Spain, began to urbanize the country with roads ...

, Partanna, Montevago, Santa Margherita di Belice,

, Salaparuta, Poggioreale.

Vita Vita or VITA (plural vitae) is Latin for "life", and may refer to: * ''Vita'', the usual start to the title of a biography in Latin, by which (in a known context) the work is often referred to; frequently of a saint, then called hagiography * Vita ...

, Salemi, and

Camporeale Camporeale ( Sicilian: ''Campuriali'') is a '' comune'' (municipality) in the Metropolitan City of Palermo in the Italian region Sicily, located about southwest of Palermo. As of 31 December 2004, it had a population of 3,652 and an area of .All ...

also suffered significant damage. The earthquakes on 14 January did little damage, but many of the inhabitants spent the following night sleeping outside, during which the most damaging of the shocks occurred, which probably greatly reduced the number of casualties. The official death toll was 231 with a further 623 injured. Other estimates give more than 400 dead with over 1,000 injured. An estimated 100,000 people were made homeless by the earthquakes. The worst affected buildings were of unreinforced masonry construction that used irregular stones with weak mortar and had roofs consisting of heavy tiles resting on wooden beams. Such buildings collapsed completely in many cases. Houses with load-bearing walls made of regular stone or concrete blocks and better quality mortar performed better, although some were badly damaged. The most modern buildings that used reinforced concrete frames generally suffered little damage.

Aftermath

The immediate relief effort was hampered by a lack of disaster relief planning at both local and provincial levels, excessive bureaucracy, a lack of supplies close to the affected areas and a tendency of refugees to treat outsiders with suspicion. One year after the earthquakes, many hundreds of people were still living in tents and many of the prefabricated housing units had yet to appear, despite having been paid for; no work had begun on providing permanent housing. Two-thirds of refugee families had still not received their government grant. Nine years after the earthquake, none of the refugees had been placed in new housing, leaving 60,000 still living in temporary accommodation. The towns of Poggioreale, Gibellina, Vita, Santa Margherita di Belice and Salaparuta were eventually rebuilt in new locations.

References

External links

* * {{DEFAULTSORT:Belice Earthquake, 1968 1968 Belice 1968 earthquakes 1968 in Italy

1968 The year was highlighted by protests and other unrests that occurred worldwide. Events January–February * January 5 – " Prague Spring": Alexander Dubček is chosen as leader of the Communist Party of Czechoslovakia. * J ...

January 1968 events in Europe Earthquake clusters, swarms, and sequences 1968 disasters in Italy