Saturday, November 5, 2016
Facts about The Lisbon Earthquake of 1755
The Great Earthquake, Tsunami and Tidal Waves of 1755
On November 1, 1755, a devastating earthquake hit Lisbon, Portugal, killing as many as 50,000 people. The city was virtually rebuilt from scratch following the widespread destruction.
Lisbon was Portugal’s capital and largest city during the prosperous 18th century, when diamonds and gold from the Portuguese colony in Brazil made many in the country wealthy. About 10 percent of Portugal’s 3 million people lived in Lisbon and, as one of the biggest ports on the Atlantic Ocean, the city played a critical role in world trade. In 1755, Lisbon was also a major center of Catholicism and was home to Catholic religious authorities.
On All Saints Day (November 1) three tremors over the course of 10 minutes suddenly struck Lisbon. The worst of the quakes is thought to have had a magnitude of 8.0, though this is just an estimate as no recording equipment existed at the time. The shaking was felt as far away as Morocco.
The devastating effects of the earthquake were felt throughout the city. Close to the coast, a 20-foot tsunami rushed ashore and killed thousands. Many people were observing All Saints Day in churches at the time and died when the buildings collapsed. Fires broke out all over the city and winds spread the flames quickly. The royal palace was destroyed, as were thousands of homes. Much of the country’s cultural history, preserved in books, art and architecture, was wiped away in an instant. Many of the city’s residents, including hundreds of escaped prisoners, fled Lisbon immediately. The death toll has been estimated at between 10,000 and 50,000.
The Marquis of Pombal was assigned the task of rebuilding the city. The twisting narrow streets that had once made up Lisbon were replaced by broad avenues. The reconstruction also featured one of the first uses of prefabricated buildings. While the rebuilding was a notable success, some used the tragedy for their own purposes. Religious authorities proclaimed that the earthquake was caused by the wrath of God, brought on the city because of its sins. The famous author Voltaire, who witnessed the quake, parodied this line of thinking along with those who insist that everything that happens is for the best in his book Candide.
Contemporary reports state that the earthquake lasted between three and a half and six minutes, causing fissures 5 meters (15 feet) wide to open in the city centre. Survivors rushed to the open space of the docks for safety and watched as the water receded, revealing a sea floor littered with lost cargo and shipwrecks. Approximately 40 minutes after the earthquake, a tsunami engulfed the harbor and downtown area, rushing up the Tagus river so fast that several people riding on horseback were forced to gallop as fast as possible to the upper grounds for fear of being carried away. It was followed by two more waves. In the areas unaffected by the tsunami fire quickly broke out, and flames raged for five days.
Lisbon was not the only Portuguese city affected by the catastrophe. Throughout the south of the country, in particular the Algarve, destruction was rampant. The tsunami destroyed some coastal fortresses in the Algarve and, in the lower levels, it razed several houses. Almost all the coastal towns and villages of the Algarve were heavily damaged, except Faro, which was protected by the sandy banks of Ria Formosa. In Lagos, the waves reached the top of the city walls. Other towns of different Portuguese regions, like Peniche, Cascais, and even Covilhã which is located near the Serra da Estrela mountain range in central inland Portugal, were affected. The shock waves of the earthquake destroyed part of Covilhã’s castle walls and its large towers. On the island of Madeira, Funchal and many smaller settlements suffered significant damage. Almost all of the ports in the Azores archipelago suffered most of their destruction from the tsunami, with the sea penetrating about 150 miles inland.
Shocks from the earthquake were felt throughout Europe as far as Finland and North Africa, and according to some sources even in Greenland and in the Caribbean. Tsunamis as tall as 20 meters (66 ft) swept the coast of North Africa, and struck Martinique and Barbados across the Atlantic. A three-meter (ten-foot) tsunami hit Cornwall on the southern English coast. Galway, on the west coast of Ireland, was also hit, resulting in partial destruction of the “Spanish Arch” section of the city wall. At Kinsale, several vessels were whirled round in the harbor, and water poured into the marketplace.
Although not the strongest or most deadly earthquake in human history, the 1755 Lisbon earthquake’s impact, not only on Portugal but on all of Europe, was profound and lasting. Depictions of the earthquake in art and literature can be found in several European countries, and these were produced and reproduced for centuries following the event, which came to be known as “The Great Lisbon Earthquake.”
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The earthquake began at 9:30 and was centered in the Atlantic Ocean about 200 km west-southwest of Cape St. Vincent. The total duration of shaking lasted ten minutes and was comprised of three distinct jolts. Effects from the earthquake were far reaching. The worst damage occurred in the south-west of Portugal. Lisbon, the Portuguese capital, was the largest and the most important of the cities damaged. Severe shaking was felt in North Africa and there was heavy loss of life in Fez and Mequinez. Moderate damage was done in Algiers and in southwest Spain. Shaking was also felt in France, Switzerland, and Northern Italy. A devastating fire following the earthquake destroyed a large part of Lisbon, and a very strong tsunami caused heavy destruction along the coasts of Portugal, southwest Spain, and western Morocco.
The oscillation of suspended objects at great distances from the epicenter indicate an enormous area of perceptibility. The observation of seiches as far away as Finland, suggest a magnitude approaching 9.0. Precursory phenomena were reported, including turbid waters in Portugal and Spain, falling water level in wells in Spain, and a decrease in water flow in springs and fountains.
Detailed descriptions of the earthquake’s effects in Morocco, were, in some cases, based on Portuguese manuscripts written by priests. The cities of Meknes, Fez, and Marrakesh in the interior, and the coastal towns of Asilah, Larache, Rabat, and Agadir (Santa Cruz during the Portuguese occupation) suffered much damage in the quake. Mosques, synagogues, churches, and many other buildings collapsed in Meknes, where numerous casualties were reported. The convent, church, and Hospital de San Francisco completely collapsed.
Immediately after the earthquake, many inhabitants of Lisbon looked for safety on the sea by boarding ships moored on the river. But about 30 minutes after the quake, a large wave swamped the area near Bugie Tower on the mouth of the Tagus. The area between Junqueria and Alcantara in the western part of the city was the most heavily damaged by the wave, but further destruction occurred upstream. The Cais de Pedra at Rerreiro do Paco and part of the nearby custom house were flattened.
A total of three waves struck the shore, each dragging people and debris out to sea and leaving exposed large stretches of the river bottom. In front of the Terreiro do Paco, the maximum height of the waves was estimated at 6 meters. Boats overcrowded with refugees capsized and sank. In the town Cascais, some 30 km west of Lisbon, the waves wrecked several boats and when the water withdrew, large stretches of sea bottom were left uncovered. In coastal areas such as Peniche, situated about 80 km north of Lisbon, many people were killed by the tsunami. In Setubal, 30 km south of Lisbon, the water reached the first floor of buildings.
Almost all the coastal towns and villages of Algarve were heavily damaged, except Faro, which was protected by sandy banks. In Lagos, the waves reached the top of the city walls. For the coastal regions, the destructive effects of the tsunami were more disastrous than those of the earthquake.
In southwestern Spain, the tsunami caused damage to Cadiz and Huelva, and the waves penetrated the Guadalquivir River, reaching Seville. In Gibraltar, the sea rose suddenly by about two meters. In Ceuta the tsunami was strong, but in the Mediterranean Sea, it decreased rapidly. On the other hand, it caused great damage and casualties to the western coast of Morocco, from Tangier, where the waves reached the walled fortifications of the town, to Agadir, where the waters passed over the walls, killing many.
The tsunami crossed the Atlantic Ocean, reaching the Antilles in the afternoon. Reports from Antigua, Martinique, and Barbados note that the sea first rose more than a meter, followed by large waves.
Can it happen again? Definitely yes!
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Paintings of Lisbon Before the Earthquake
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Paintings of Lisbon After the Earthquake
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