The Historical Reconstruction of the 1755 Earthquake and Tsunami in Downtown Lisbon, Portugal
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Journal of Marine Science and Engineering Article The historical reconstruction of the 1755 earthquake and tsunami in downtown Lisbon, Portugal Angela Santos 1,* , Mariana Correia 1, Carlos Loureiro 2, Paulo Fernandes 2,3 and Nuno Marques da Costa 1 1 Centre for Geographical Studies, Institute of Geography and Spatial Planning, Universidade de Lisboa, Rua Branca Edmée Marques, 1600-276 Lisboa, Portugal 2 Museu de Lisboa, EGEAC, Campo Grande 245, 1700-091 Lisboa, Portugal 3 Centro de Estudos em Arqueologia, Artes e Ciências do Património, Universidade de Coimbra, 3000-395 Coimbra, Portugal * Correspondence: [email protected]; Tel.: +351-210-443-000 Received: 1 April 2019; Accepted: 27 June 2019; Published: 4 July 2019 Abstract: The historical accounts of the 1755 earthquake and tsunami in Lisbon are quite vast providing a general overview of the disaster in the city. However, the details remain unknown. Therefore, the objective of this research is to understand and reconstruct the impact of the 1755 event (earthquake, tsunami, and fire) in downtown Lisbon. Thus, the historical data has been compiled and analyzed, to complement tsunami modeling and a field survey. Although census data are not very accurate, before the disaster there were about 5500 buildings and about 26,200 residents in downtown Lisbon; after the disaster, no records of the buildings were found and there were about 6000–8800 residents. There were about 1000 deaths in the study area. The results also show that the earthquake did not cause significant damage to most of the study area, which contradicts general knowledge. After the earthquake, a fire started that quickly spread throughout the city causing most damage to property. The tsunami hit mostly the west and central parts of the study area. The numerical model results show the tsunami hit the studied area about 60 min after the earthquake, inundating the seafront streets and squares up to 200 m inland. In addition, two major waves were calculated, which are in agreement with the historical accounts. Keywords: 1755 tsunami; downtown Lisbon; historical data; numerical model 1. Introduction The 1 November 1755 earthquake triggered a tsunami that hit the entire Portuguese coastline. According to the historical records previously analyzed [1] in Lisbon municipality, the combined effects of the earthquake, tsunami, and fire caused significant damage to the city’s buildings. However, the administrative limits of Lisbon municipality have been changing over time, which has been one of the limitations in the interpretation of this historical event in the city. Still, it is known that the disaster killed more than 10,000 people [1] in the municipality, which in 2010 had 54 civil parishes. Moreover, the 18th century census data show that before the earthquake Lisbon city had 109,754–157,192 residents (older than 7 years). As a result, the fatalities due to the 1755 disaster correspond to 6.4%–9.1% of the Lisbon city resident population [1]. The recovery process started immediately after the disaster. Nevertheless, only on 12 May 1758 was the Reconstruction Law of Lisbon approved [2]. It established a five-year period to conclude the reconstruction project. On the other hand, although the historical accounts are quite vast providing a general overview of the disaster in the Lisbon municipality, details remain unknown, especially in the downtown area. In addition, the 1755 event has been largely J. Mar. Sci. Eng. 2019, 7, 208; doi:10.3390/jmse7070208 www.mdpi.com/journal/jmse J. Mar. Sci. Eng. 2019, 7, 208 2 of 21 J. Mar. Sci. Eng. 2019, 7, x FOR PEER REVIEW 2 of 20 discussedcommunity, among however, the public, the authors stakeholders did not and find scientific any published community, detailed however, analysis the of authors the disaster did not in find the anyLisbon published municipality. detailed analysis of the disaster in the Lisbon municipality. Therefore,Therefore, thethe aimaim of of this this research research is is to to understand understand and and reconstruct reconstruct the the impact impact of of the the 1755 1755 event event in downtownin downtown Lisbon, Lisbon, which which includes includes earthquake, earthquake, tsunami, tsunami, and fire and damage fire damage and the and number the number of victims, of asvictims, well as as tsunami well as parameters tsunami parameters (travel times, (travel number times, of wavesnumber and of inundationwaves and area). inundation The study area). area The is presentedstudy area in is Figurepresented1, corresponding in Figure 1, corresponding to a stretch of to coastline a stretch of of about coastline 1.8 km, of about including 1.8 km, only including 5 civil parishesonly 5 civil (out parishes of 54 administrative (out of 54 administrative limits of Lisbon limits city inof 2010).Lisbon This city area in 2010). was selected This area due was to available selected datadue to and available relevance data to and the relevance comprehensive to the comprehe analysis ofnsive the tsunami.analysis of Furthermore, the tsunami. Furthermore, this research isthis a collaborationresearch is a collaboration between academia between and academia the Museum and the of Lisbon,Museum which of Lisbon, is quite which innovative is quite in innovative Portugal. Within Portugal. this research, With thethis authors research, hope the to contributeauthors hope to a clearerto contribute and objective to a understandingclearer and objective of this historicalunderstanding event inof downtownthis historical Lisbon event and in to downtown advance the Lisbon general and knowledge to advance about the thisgeneral historical knowledge event thatabout has this not historical been properly event addressedthat has not or been discussed. properly addressed or discussed. FigureFigure 1.1. Geographical setting of the study area: ( a) Location of Portugal and the Lisbon municipality; ((bb)) locationlocation ofof thethe studystudy area;area; ((cc)) detailsdetails ofof thethe studystudy area,area, which which in in 2010 2010 had had 5 5 civil civil parishes. parishes. 2.2. Review of the Seismo-Tectonics OOffshoreffshore ofof thethe PortuguesePortuguese MainlandMainland TheThe seismo-tectonicsseismo-tectonics o offshoreffshore of of the the Portuguese Portuguese mainland mainland show show that that the the current current tectonic tectonic regime regime at theat the boundary boundary of the of African the African and Eurasian and Eurasian plates isplates located is withinlocated 35–40 within◦N. This35–40°N. boundary This isboundary commonly is dividedcommonly into divided three sections into three [3], sections presented [3], in presented Figure2([ in4]): Figure (i) the 2 Azores([4]): i) Sectionthe Azores (35◦ SectionW to 24 (35°W◦W): the to feature24°W): thatthe feature dominates that thedominates Azores the section Azores is the section triple is point the triple where point the Northwhere American,the North EuroasianAmerican, andEuroasian African and plates African join. Theplates Terceira join. The Ridge Terceira is responsible Ridge is for responsible the active for volcanism the active found volcanism in the Azores found islands.in the Azores (ii) The islands. Central ii) SectionThe Central (24◦ WSection to 13 ◦(24°WW): the to main13°W): feature the main is the feature Gloria is Fault,the Gloria a rectilinear Fault, a right-lateralrectilinear right-lateral fault. The east fault. end The of thiseast faultend isof notthis well fault defined; is not well (iii) defined; the East sectioniii) the (13East◦W section to 5◦W): (13°W the to 5°W): the tectonics of the East section (see the rectangle in Figure 2) is governed by the interaction between the Euroasian and African plates [5]. This is a region of complex bathymetry with a very low J. Mar. Sci. Eng. 2019, 7, 208 3 of 21 J.tectonics Mar. Sci. Eng. of the 2019 East, 7, x sectionFOR PEER (see REVIEW the rectangle in Figure2) is governed by the interaction between3 of the 20 Euroasian and African plates [5]. This is a region of complex bathymetry with a very low convergence 1 −1 convergencerate of 4 mm rate yr− of[6, 74], mm trending yr [6,7], NW–SE, trending consistent NW– withSE, consistent the observed with maximum the observed horizontal maximum stress horizontaldirection [ 8stress–11]. direction The transition [8–11]. between The transition the localized between and the di fflocalizeduse plate and boundary diffuse mayplate be boundary due to a maychange be indue the to nature a change and in age the of nature the lithosphere and age of [12 th].e Thelithosphere main bathymetry [12]. The main structures bathymetry of the East structures section ofare the presented East section in Figure are presented3. in Figure 3. Figure 2. PlatePlate tectonics tectonics of the Atlantic North East, and th thee location of the east section. The rectangle on the east section will be explained in more detail [[4].4]. The East Section is dominated by the Gorringe Bank (Figure3 3).). ItIt isis orientatedorientated inin aa SW–NESW–NE direction, consistent with the tectonics of the regi region,on, where the stress field field is dominated by a trending trending approximately inin thethe NW–SE NW–SE direction direction [5 ].[5]. It hasIt has dimensions dimensions of 200 of 200 km bykm 80 by km 80 and km reaches and reaches 25 m below 25 m belowthe mean the sea mean level, sea separating level, separating Tagus and HorseshoeTagus and Abyssal Horseshoe Plaines Abyssal (Figure 3Plaines); it is asymmetrical, (Figure 3); withit is asymmetrical,the northern flank with steeper the northern than the flank southern. steeper Gorringe than Bankthe southern. consists ofGorringe 2 seamounts, Bank the consists Gettysburg of 2 seamounts,Seamount, in the the Gettysburg Southwest Seamount, and Ormonde in the Seamount, Southwest in theand Northwest, Ormonde separatedSeamount, by in athe saddle-shaped Northwest, separatedstructure [by13 –a15 saddle-shaped]. An idea of structure a thrust origin[13–15]. for An the idea Gorringe of a thrust Bank origin has beenfor the supported Gorringe byBank in situhas beencore sampling.supported Aby deep in situ sea core drilling sampling.