Sedimentary record of a tsunami during Roman times, Bay of Cadiz, Spain

Abstract

Historical data show that the Gulf of Cadiz has been exposed to destructive tsunamis during at least the past 2000 yr. The last tsunami was generated by the AD 1755 Lisbon earthquake, which affected the Atlantic coasts of Spain, Portugal and Morocco. Today, these littoral areas are intensely populated and the expected damage could be much greater. Tsunami studies are of great importance in helping to determine the recurrence interval of these events.The presence of washover fan deposits on the inland margin of the Valdelagrana Spit bar (Cadiz, Spain) indicates the occurrence of a high energy marine event ca. 2300 cal. yr BP. Historical, geomorphological, sedimentological, palaeontological and geochronological data suggest that a tsunami could have affected the area during Roman times.

Revision of the Portuguese catalog of tsunamis

“…3.6 The 2.2-2.3 kyr BP paleotsunami A high energy event 2200-2300 yr BP was positively identified by Luque et al (2002) on the Valedelagrana Spit Bar (Bay of Cadiz, Spain), with the input of coarse sands into tidal marsh deposits, similar to the sedimentary signature of the 1755 event in the same place. Vizcaino et al (2006) found a similar result for a debris flow in the Marques de Pombal core, attributing it a radiocarbon age of 2293±35 yr BP.…”

Holocene palaeotsunami catalogue of SW Iberia

“…Cadiz coast have been noted in many places along shore, such as the key-points of Punta Umbria, Dofiana, and Valdelagrana (Lario et al, 1995(Lario et al, a, 2001b(Lario et al, , 2002Lario, 1996;Dabrio et al, 1999;Luque et al, 2002;Ruiz et al, 2004, 200Sb ;Caceres et al, 2006). Wide spread occurrence of EWE features along the coast (breaching of spit barriers, intruding sandy layers with marine bioclasts in the inner estuaries, chenier development, occurrence of washover fans) and other effects of regional extent, such as the reorganisation of the back barrier drainage patterns of estuaries (e.g.…”

“…It must be also considered that, although Galbis The well-documented 1755 Lisbon tsunami-earthquake is clearly associated with the E3-turbidite in the off-shore record (Gracia et al, 2010). This recent EWE has an abundant historical written record for more than 30 sites along the south-western Spanish shores, complemented by extensive analyses of its geological effects on the Gulf of Cadiz area (Campos, 1991;Dabrio et al, 1999;Martinez Solares, 2001;Luque et al, 2001Luque et al, , 2004Luque, 2002;Morales et al, 200S;Lario et al, 2010).…”

“…Most surveys of EWEs in the area have concentrated on: Guadalquivir (Lario et al, 1995(Lario et al, , 2001aLario, 1996;Ruiz et al, 2004Ruiz et al, , 2005Caceres et al, 2006), Tinto-Odiel (Lario, 1996;Ruiz et al, 2007;Morales et al, 2008), and Guadalete (Lario et al, 1995;Lario, 1996;Dabrio et al, 1999;Luque et al, 2001Luque et al, , 2002 estuaries, the littoral lowland on the south-eastern coast of the Gulf of Cadiz (Luque, 2002;Kelletat, 2003, 2005;Alonso et al, 2004;Luque et al, 2004), and the Algarve ( Andrade, 1992;Dawson et al, 1996) ( Fig. 1).…”

Eventos marinos y asentamientos costeros en el suroeste de Iberia

“…Posteriormente, varias publicaciones han evidenciado este evento en distintos lugares de la costa atlántica (Luque et al, 2001(Luque et al, , 2002Silva et al, 2015, entre otros), hasta que finalmente ha sido asimilado a un tsunami que se produjo a finales del siglo III a.C., posiblemente entre el 218 y 209 a.C. (Rodriguez-Vidal et al, 2011), coincidiendo con la Segunda Guerra Púnica. Silva et al (2015) proponen denominarlo como "Lacus Ligustinus Earthquake", utilizando para ello el nombre del antiguo lugar geográfico donde se han recogido la mayor parte de sus evidencias geológicas (Rodríguez-Vidal et al, 2011).…”