New Geological Evidence of the 1755 Lisbon Tsunami from the Rock of Gibraltar (Southern Iberian Peninsula) (original) (raw)
Related papers
The sedimentary inventory of tsunamis along the southern Gulf of Cadiz (southwestern Spain)
Zeitschrift f&# 252; r …, 2010
Outcrop evidence and shallow percussion drilling in coastal areas proved sedimentary evidence for paleo-tsunamis along a 50 km long segment of the Atlantic coast of southern Spain. The coast between Barbate and Tarifa yielded several depositional environments to preserve tsunamigenic layers, both on top of rocky cliffs as well as in lagoons, marshlands and along sedimentary beaches. Also, we focused on bays with river inlets, which are most probably sheltered from direct tsunami wave action. In these bays, the Roman villages of Baelo Claudia and Mellaria are situated. We found no evidence for tsunamigenic sediments there. On the other side, the findings of an enigmatic, most probable tsunamite has been encountered upon the cliff along the Barbarte-Zahara de los Atunes beach in various heights above mean sea level. Because only one dark-colored fining-up layer with a paleocurrent direction towards the sea has been found directly resting on folded Betic substratum, we interpret this layer as tsunamigenic back wash sediments. The last major event that affected severely the coast of the Gulf of Cádiz was the 1755 Lisbon tsunami. Reportedly, wave heights reached > 10 m in the study area. So, it is likely that coastal changes and deposition of tsunamigenic sediments in this area occurred, being attributed to this 1755 event. However, also older sedimentary relicts of tsunamis have to be taken into account, because sedimentary cores yield evidence for multiple intercalations.
Geosciences, 2020
The CE 1755 Lisbon tsunami was the largest historical tsunami to affect the Atlantic coasts of Europe and North Africa. This study presents the results obtained from the application of different sedimentological techniques (e.g., grain size, morphoscopy, microtextural analysis, geochemistry, radiocarbon dating) on sediments retrieved from the Alcabrichel River alluvial plain (of about 500 m far away from its mouth and approximatively 50 km northwest of Lisbon, Portugal). The results allowed the identification of a sandy layer that was associated with the CE 1755 tsunami. Furthermore, a new microtextural semi-quantitative classification was applied to enhance the identification of extreme marine inundation deposits. Based on sedimentological data, three different tsunami inundation phases were identified, including two inundations and a likely backwash. This innovative work offers physical evidence of the spatial presence of the CE 1755 tsunami event on the western coast of Europe. I...
Science of Tsunami Hazards, 2005
Field evidence of visible tsunami impacts in Europe is scarce. This research focused on an analysis of large littoral debris and accompanying geomorphic features and their relationship to a tsunami event at Cabo de Trafalgar, located on the southern Spanish Atlantic coast. Relative dating of weathering features as well as minor bioconstructive forms in the littoral zone suggest the Lisbon tsunami of 1755 AD as the event responsible for the large deposits described. This tsunami had run up heights of more than 19 m and was generated at the Gorringe Bank, located 500 km west off the Cape. Tsunami deposits at Cabo de Trafalgar are the first boulder deposits identified on the southern Spanish Atlantic coast and are located approximately 250 km southeast of the Algarve coast (Portugal), where other geomorphic evidence for the Lisbon tsunami has been reported.
The recorded evidence of AD 1755 Atlantic tsunami on the Gibraltar coast
Journal of Iberian …, 2011
Evidence of the AD 1755 tsunami consisting of the same type of accretions produced by the re-deposition of earlier sediments, has been recorded at three different height along the coast of Gibraltar: Along a shallow sandy shore, the tsunami wave reached a run-up of 2-3 m, whereas along steep, cliff-lined shores (Rosia Bay) it surpassed 5 m. An overwash deposit was also identified at the bottom of a lagoon (The Inundation), at 0.5 m b.s.l., on the isthmus that joins the Rock with the mainland. Southern submerged platforms (Vladi's Reef) were also affected by the erosional backwash to a depth of 22 m. The tsunamigenic sediments exhibit a bimodal granulometry, mainly composed of sands with a coarser fraction composed of marine faunal shells remains, together with larger clasts derived from the rocky substrate. All remobilized sediments were dated by historical methods and radiocarbon dating.
SCIENCE OF TSUNAMI HAZARDS, 2021
A spectacular earthquake struck the southern margin of the Iberian Peninsula and part of the western fringe of North Africa in 881 AD. Historical sources suggest it was followed by a tsunami. However, the origin and characteristics of this event are yet to be determined. We present evidence, both historical and geo-archaeological, of a tsunami and outline the characteristics for the catastrophe. The presence of a sedimentary layer rich in marine and continental materials, appears to be of a tsunami backwash artifact, and in addition to archaeological remains, provides compelling data supporting our present study.
Palaeogeography, Palaeoclimatology, Palaeoecology, 2018
A multiproxy study combining paleomagnetic, rock magnetic (magnetic susceptibility; anhysteretic remanent magnetization, ARM; isothermal remanent magnetization, IRM, anisotropy of magnetic susceptibility, AMS) and geochemical (XRF) data was carried out on trench sediments collected in the area of Boca do Rio (Algarve, South Portugal) known to have been stricken by a tsunami wave related to the 1755 Lisbon earthquake. The magnetic mineral assemblage is dominated by multidomain ferrimagnetic grains with a significant contribution (5-9%) of ultra-fine magnetic particles related to the presence of pedogenetic magnetite. The variable amount of this post-depositional magnetite plays a role on the characteristic remanent magnetization (ChRM) of the sediment. The primary magnetization recorded at T1, located farthest from the coast, is representative of the paleosecular variation of the Earth's magnetic field and a comparison of the results with the regional model for the geomagnetic field in Europe (SCHA.DIF.3K) was used to constrain the erosional signature of the tsunami layer. The result indicates that less than eighty years could be missing in the sedimentary column. The eroded sediment (thickness 27-40 cm) was
Sedimentary record of a tsunami during Roman times, Bay of Cadiz, Spain
Journal of Quaternary Science, 2002
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.
Radiocarbon, 2007
At 2 locations of the southern Spanish coast, we found indications for tsunamis induced by submarine earthquakes. Charcoal, which we sampled in 2 stratified, assumed tsunamigenic sediment (tsunamites) layers at the shore outside the ruins of the Roman city of Baelo Claudia, close to the Strait of Gibraltar (province of Cadiz), and radiocarbon dated, surprisingly turned out to be of identical age, about 465 BR In the laguna of the Cabo de Gata (province of Almeria), we found possible remnants of tsunamites in drilling cores deposited above organic sediments, I4 C dated as 680 ± 30 BR