Shallow-marine sediment cores record climate variability and earthquake activity off Lisbon (Portugal) for the last 2000 years

Abrantes, Fatima F; Lebreiro, Susana Martin; Rodrigues, Teresa; Gil, Isabelle M; Bartels-Jonsdottir, Helga B; Oliveira, Paulo B.; Kissel, Catherine; Grimalt, Joan O.

doi:10.1016/j.quascirev.2004.04.009

Cited by 132 publications

(138 citation statements)

References 65 publications

Supporting

Mentioning

124

Contrasting

Unclassified

Order By: Relevance

“…These proportions are similar to those estimated by Abrantes et al (2005) off Lisbon (Portugal), where this tsunami caused the loss of 39 cm of sediment and the instantaneous deposition of a 19 cm sediment bed.…”

Section: Cliffed Coast Evidencesupporting

confidence: 87%

“…This material, trapped in the surface of these cavities may be considered as a subaqueous tsunami deposit. Sandy submarine tsunamites have been described for this same event in the continental platform in front of the mouth of River Tagus in Lisbon (Abrantes et al, 2005). A very similar situation with cave-fillings has been described by Mörner and Dawson (2011) in the Maldives islands.…”

Section: Results For Vladi's Reefsupporting

confidence: 59%

“…So the AD 1755 Lisbon earthquake triggered only a thin turbidite (< 20 cm thickness near the Mârques de Pombal fault) . This turbidite has been studied and identified by Thomson and Weaver (1994), Lebreiro et al (1997), Abrantes et al (2005) and Vizcaino et al (2006).…”

Section: Portuguese Coastmentioning

confidence: 99%

“…With regard to the tsunami sedimentary evidence in the Portuguese coast, and according to Abrantes et al (2005) the energy of this tsunami at the mouth of Tagus River, in Lisbon, was estimated to have eroded 160-355 years of the sedimentary marine record and instantaneously deposited a 19 cm sediment bed consisting of a lower layer of silt sized heavy mineral particles, followed by a coarser layer composed of reworked shell fragments.…”

Section: Portuguese Coastmentioning

confidence: 99%

See 3 more Smart Citations

The recorded evidence of AD 1755 Atlantic tsunami on the Gibraltar coast

Rodriguez‐Vidal

Puro

Abad

et al. 2011

Journal of Iberian Geology

View full text Add to dashboard Cite

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.Keywords: Lisbon earthquake, AD 1755 tsunami, run-up, sedimentary record, radiocarbon dating, Gibraltar ResumenSe han registrado evidencias del tsunami de 1755 localizadas a tres alturas diferentes a lo largo de la costa de Gibraltar, todas ellas como resultado del mismo tipo de acreción producida por el re-depósito de sedimentos previos. A lo largo de las costas bajas y arenosas estudiadas, la ola del tsunami alcanzó una altura de 2 a 3 m, mientras que en litorales acantilados y con fuertes pendientes ISSN (print): 1698-6180. ISSN (online): 1886-7995

show abstract

Section: Cliffed Coast Evidencesupporting

confidence: 87%

Section: Results For Vladi's Reefsupporting

confidence: 59%

Section: Portuguese Coastmentioning

confidence: 99%

Section: Portuguese Coastmentioning

confidence: 99%

See 2 more Smart Citations

The recorded evidence of AD 1755 Atlantic tsunami on the Gibraltar coast

Rodriguez‐Vidal

Puro

Abad

et al. 2011

Journal of Iberian Geology

View full text Add to dashboard Cite

show abstract

“…Extensive geological evidence of tsunami deposits associated with the 1755 earthquake has been reported in Europe (e.g. Andrade 1992;Dawson et al 1995;Abrantes et al 2005;Scheffers and Kelletat 2005). The problem of epicentral location has been addressed by various early studies (Reid 1914;Pereira de Sousa 1919), and since the beginning of the instrumental period, a consensus has attributed the origin of the earthquake to a structure located between the Gorringe Bank and the Coral Patch Ridge (Machado 1966;Moreira 1985;Johnston 1996;Grandin et al 2007b;Barkan et al 2009).…”

Section: Ground Motion Simulations and Earthquake Sourcementioning

confidence: 99%

Ground motion simulations of the SW Iberia margin: rupture directivity and earth structure effects

2011

View full text Add to dashboard Cite

In this study, we focus on the region between Gorringe Bank and the Horseshoe Fault located in the SW Iberia margin, which is believed to be the site of the great 1755 earthquake. We model ground motions using an extended source located near the Horseshoe scarp to generate synthetic waveforms using a wave propagation code, based on the finite-difference method. We compare the simulated waveforms, for the Algarve Basin and the Lower Tagus Valley Basin (Portugal), using a 3-D velocity model down to the Moho discontinuity with a simple 1-D layered model. The radiated wave field is very sensitive to the velocity model and a small number of source parameters, in particular, the rupture directivity. The rupture directivity, the strike direction and the fault dimensions are critical to the azimuthal distribution of the maximum amplitude oscillations. We show that the use of a stratified 1-D model is inappropriate in SW Iberia, where sources are located in the oceanic domain and receivers in the continental domain. The crustal structure varies dramatically along the ray paths, with large-scale heterogeneities of low or high velocities. Moreover, combined with the geometric limitations inherent to the region, a strong tradeoff between several parameters is often observed; this is particularly critical when studying moderate magnitude earthquakes (M \ 6), which constitute the bulk of the seismic catalogue in SW Iberia.

show abstract

Boulder deposition during major tsunami events

Costa

Andrade

Freitas

et al. 2011

Earth Surf Processes Landf

View full text Add to dashboard Cite

Abstract:A remarkable accumulation of marine boulders located above the present spring tide level has occurred in two coastal lowlands of the Algarve (Portugal). The size-interval of the particles studied here is seldom reported in the literature in association with extreme events of coastal inundation, thus making this study of relevance to many other coasts worldwide. The spreads of boulders extend several hundred meters inland and well beyond the present landward limit of storm activity. The marine origin of the boulders is demonstrated by well-developed macro-bioerosion sculpturing and in situ skeletal remains of endolithic shallow marine bivalves. The good state preservation of the fossils within the boulders indicates that abrasion duringtransport and redeposition was not significant. We envisage boulder deposition as having taken place during the Lisbon tsunami of ad 1755 through the simultaneous landward entrainment of coarse particles from nearshore followed by rapid shoreward suspended-dominated transport and non-graded redeposition that excluded significant sorting by weight or boulder dimensions. We use numerical hydrodynamic modeling of tsunami (and storm) waves to test the observational data on boulder dimensions (density, size, distribution) on the most likely processes of sediment deposition. This work demonstrates the effectiveness of the study of boulder deposits in tsunami reconstruction.

show abstract

Shallow-marine sediment cores record climate variability and earthquake activity off Lisbon (Portugal) for the last 2000 years

Cited by 132 publications

References 65 publications

The recorded evidence of AD 1755 Atlantic tsunami on the Gibraltar coast

The recorded evidence of AD 1755 Atlantic tsunami on the Gibraltar coast

Ground motion simulations of the SW Iberia margin: rupture directivity and earth structure effects

Boulder deposition during major tsunami events

Contact Info

Product

Resources

About