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The 1755 Lisbon earthquake, also known as the Great Lisbon earthquake, occurred in the Kingdom of Portugal on Saturday, 1 November, the holiday of All Saints' Day, at around 09:40 local time.〔(Between History and Periodicity: Printed and Hand-Written News in 18th-Century Portugal )〕 In combination with subsequent fires and a tsunami (maremoto in Portuguese), the earthquake almost totally destroyed Lisbon and adjoining areas. Seismologists today estimate the Lisbon earthquake had a magnitude in the range 8.5–9.0〔"(Historic Earthquakes – Lisbon, Portugal )." U.S. Geological Survey, October 26, 2009. 〕 on the moment magnitude scale, with its epicentre in the Atlantic Ocean about 200 km (120 mi) west-southwest of Cape St. Vincent. Estimates place the death toll in Lisbon alone between 10,000 and 100,000 people,〔Pereira (2006), page 5.〕 making it one of the deadliest earthquakes in history. The earthquake accentuated political tensions in the Kingdom of Portugal and profoundly disrupted the country's colonial ambitions. The event was widely discussed and dwelt upon by European Enlightenment philosophers, and inspired major developments in theodicy. As the first earthquake studied scientifically for its effects over a large area, it led to the birth of modern seismology and earthquake engineering. ==Earthquake and tsunami== In 1755, the earthquake struck on the morning of 1 November, the holiday of All Saints' Day. Contemporary reports state that the earthquake lasted between three and a half and six minutes, causing fissures 5 metres (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 harbour and downtown area, rushing up the Tagus river,〔Viana-Baptista MA, Soares PM. Tsunami propagation along Tagus estuary (Lisbon, Portugal) preliminary results. ''Science of Tsunami Hazards'' 2006; 24(5):329 (Online PDF ). Accessed 2009-05-23. (Archived ) 2009-05-27.〕 "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 m inland. Shocks from the earthquake were felt throughout Europe〔''An Extraordinary and Surprising Agitation of the Waters, ...'', Philosophical Transactions, Vol. 49, (1755 - 1756) , pp. 351-398, ()〕〔''Memoirs of Jacques Casanova'', Book 2, Ch. XXVI; Casanova himself noted feeling the shocks when he was imprisoned in "The Leads" in Venice and specifically states they were the same that destroyed Lisbon〕 as far as Finland and North Africa, and according to some sources even in Greenland〔Brockhaus' Konversations-Lexikon. 14th ed., Leipzig, Berlin and Vienna 1894; Vol. 6, p. 248〕 and in the Caribbean.〔Lyell, Charles. ''Principles of Geology''. 1830. Vol. 1, chapter 25, p. 439 (Online electronic edition ). Accessed 2009-05-19. (Archived ) 2009-05-21.〕 Tsunamis as tall as 20 metres (66 ft) swept the coast of North Africa, and struck Martinique and Barbados across the Atlantic. A three-metre (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.〔 In 2015, it was revealed that the tsunami waves may have reached the coast of Brazil, then a colony of Portugal. Such hypothesis was raised by reviewing letters sent by Brazilian authorities by the time of the earthquake. Such letters describe damage and destruction caused by gigantic waves. Although seismologists and geologists have always agreed that the epicentre was in the Atlantic to the West of the Iberian Peninsula, its exact location has been a subject of considerable debate. Early theories had proposed the Gorringe Ridge until simulations showed that a source closer to the shore of Portugal was required to comply with the observed effects of the tsunami. A seismic reflection survey of the ocean floor along the Azores–Gibraltar Transform Fault has revealed a 50 km-long thrust structure southwest of Cape St. Vincent, with a dip-slip throw of more than 1 km. This structure may have created the primary tectonic event.〔Zitellini N. et al., The tectonic source of the 1755 Lisbon earthquake and tsunami. Anali di Geofisica 1999; 42(1): 49. (Online PDF ). Accessed 2009-05-23. (Archived ) 2009-05-27.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「1755 Lisbon earthquake」の詳細全文を読む スポンサード リンク
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