VOLCANO MADNESS: [Geology2] Lisbon Earthquake, 1 November 1755

Tuesday, November 1, 2011

[Geology2] Lisbon Earthquake, 1 November 1755

Lisbon Earthquake, 1 November 1755

_{Images from the Kozak Collection, Earthquake Engineering Research Center}

Lisbon, Portugal, was struck by a great earthquake on 1 November 1755. This copper engraving, made that year, shows the city in ruins and in flames. Tsunamis rush upon the shore, destroying the wharfs. The engraving is also noteworthy in showing highly disturbed water in the harbor, which sank many ships. Passengers in the left foreground show signs of panic.

The Lisbon earthquake struck in mid-morning during a high religious holiday, All Souls Day. Shortly afterward, three large tsunamis swept over the city's harbor and killed many thousands of refugees. A week later, after untameable fires and unremitting aftershocks, essentially the whole city of Lisbon was in ashes, its people scattered, and perhaps half of its population dead. The eyewitness account of the Lisbon earthquake and its aftermath by Rev. Charles Davy makes horrifying reading. Only the 1906 San Francisco earthquake is comparable in its economic and psychic impact.

In this picture, people are camping in the ruins. Signs of crime, disorder, and disease are evident, and the authorities are dealing justice to criminals as priests attend. Similar scenes occurred throughout Portugal, in southern Spain, and in Morocco. Tsunamis struck countries as far away as England and were detected across the Atlantic Ocean.

The Lisbon earthquake destroyed a major cultural center of Europe, dealing a severe blow to the nation of Portugal. Its widespread physical effects aroused a wave of scientific interest and research into earthquakes. It can be said to be the slap that started the infant science of seismology breathing. Today the quake is thought to have had a magnitude well above 8.5 and an epicenter some 200 kilometers off the southwestern corner of Portugal. Studies of the written records are still yielding fresh hypotheses.