Vaiont Dam disaster, Italy - 1963

Date

Date

9th October 1963

Type of mass movement occurred at about 10:39 pm

Rockslide

Location of Vaiont Dam disaster

Longarone, Italy. Approx 60 miles north of Venice. Construction of the dam began in 1957, resevoir began filling in Feb 1960

Main cause of Vaiont Dam disaster

720 million tonnes of rock slipping down the mountain

Speed of the rockslide in Vaiont Dam disaster

Waves travelled at over 30mph

Impact of Vaiont dam disaster

More than 2056 fatalities, 1269/1328 (94%) of Longarone's population

Human causes: warnings

No official warnings coming from the authorities

Human causes: several previous landslides

Had been covered up: a local nespaper suggested landslides were recurrent after tha resevior started filling in 1960, but legal action was taken for 'spreading false news'

Physical causes: HEP dam

Causes cracks to appear in Mt. Toc. The mountain became waterlogged. The rocks were dipping down towards the bottom of the valley, creating natural slip planes

Physical causes: reservoir

Led to an increase in groundwater pore pressure as the water table rose in the rocks

Physical causes: trigger

Period of heavy rainfall, which increased shear stress: added volume and weight to the slope as well as lubrictaing stacks of clay within the slope

Impacts on buildings and inhabitants

22/372 buildings in Longarone collapsed

Impact on human

5000 inhabitants with nowhere to go, 2000 died

Impacts: earth tremors

Strong earth tremors, recorded as far away as Vienna and Brussels

Impacts: wave of water

Washed above the lake to Cass and Erto (communities above the reservoir) where the air blast and water caused at least 158 fatalities

Impact: towns destroyed

5 downstream towns destroyed, inc Longarone, Pirago, Rivalta, Villanova and Fae

Responses: suing for negligence and manslaughter

Days before the disaster, the mayor of Erto issued an evacuation notice but the telephone messages said that it would be 'just maybe a little water over the same tonight, nothing special'

Long term: where were the survivors moved?

A newly built village called Vajont municipality, 50km southeast, having been discouraged from resturning to Erto and Casto

Long term: memorials

2002, the dam was opened up to the public with guided tours. 2013 50th anniversary, the region of Venice allocated 1million euros for safety works and recovery of road tunnels inside Mt Toc