The Late Pleistocene ami Holocene evolution of the estuaries in !he Gulf of Cadiz is interpreted for the first time using drill cores, logs, trenches, and 38 new radiocarbon data, and the results compared with lhe she!f The Odie!, Tinto and Guadalete Rivers deposited conglomerales during a highstand lhat did not reach the present sea level dated al ca. 25-30 ka (Isotopic Stage (IS) 3), corresponding lo a relatively humid period in the area. Rivers incised these coarse-grained deposits during the last main lowsland at ca. 18 ka, when sea level dropped to -120 m and the coastline lay 14 km seawards from !he presenL The erosional surface is a sequence boundary and the f100ding slIrface of tl1e postglacial eustatic rise, overlain by !he valley fill deposits of the transgressive and highstand phases of the last fourth-and fif!h-order depositional sequences recognised in !he shelf The first marine int1uence in the estuaries during the transgression occurs at -25/ -30 m at ca. 10,000 years BP. According to tossil assemblages, the transgressed basins changed fmm brackish to more open marine as !he sea rose lIntil ca. 6500 years BP, when it reached !he maximum f100ding ami the sandy estuarine barriers ceased to retrograde toward the muddy central basins. Then, the rate of eustatic rise decreased drastically, and !he estuarine filling followed a two-fold pattem govemed by the progressive change from vertical accretion to lateral (centripelal) progradation. At ca. 4000 years BP the t1uvial input surpassed !he already negligible rate of rise, causing partial emergence of tidal f1ats and spit barriers in the largely filled estuarine basins. Prevalence of coastal progradation upon vertical accretion al ca. 2400 years BP caused accelerated expansion of tidal t1ats and rapid growth of the sandy barriers. Further changes since the 16th century ref1ect widespread anthropic impacts.

This study represents the first paleoseismic approach in Spain in which archaeological remains are considered. The ancient Roman city of Baelo Claudia (1st-4th centuries AD), located at the axial zone of the Gibraltar Strait (Cadiz, south Spain), contains abundant disrupted architectural relics and ground collapses (i.e. landsliding, liquefacion) probably related to historic earthquake damage of intensity IX-X MSK. The archaeological stratigraphy of the city evidence two major episodes of abrupt city destruction bracketed in AD 40-60 and AD 350-395 separated by an intervening horizon of demolition for city rebuilding, otherwise characteristic for many earthquake-damaged archaeological sites in the Mediterranean. The second episode led the eventual city abandonment, and it is evidenced by good examples of column collapse, distortion, failure and breakdown of house and city walls, and pavement warping and disruptions documented during different archaeological excavations, which can be catalogued as secondary coseismic effects. Main damaged relicts observable today are the set of pop-up like arrays and warping developed in the ancient Roman pavement. Their analysis indicate an anomalous westwards ground displacement oblique to the main gentle southward slope of the topography, as also evidence failures, collapses and breakdown of walls and columns, suggesting that stress acted in a broad SW-NE/WSW-ENE orientation consistent whit the expectable motion along the largest NE-SW strike-slip faults of the zone, which in turn can be catalogued as seismic sources of moderate events (ca. 5 mb). Major disruptions and city abandonment were hesitantly related to relatively far strong earthquakes occurred during the late 4th century AD in the Mediterranean or western coast of Iberia by Menanteau et al. [Menanteau, L., Vanney, J.R., Zazo, C., 1983. Belo II : Belo et son environment (Detroit de Gibraltar), Etude physique d'un site antique. Pub. Casa de Velazquez, Serie Archeologie 4., Ed. Broccard, París.]. However, this study indicates that the occurrence of close moderate earthquakes jointly with the unstable character of the ground at the zone (site effect) is a more reliable hypothesis to explain the observed deformations. D

SlUlll ll ary.Sedimentological and palaeoecological observations, accompanied by archaeological determinations and absolute dating, have been carried out on a recent beach-barrier system succes sion located 20 km south of Siracusa, south-eastern Ionian coast of Sicily (Italy) . These deposits fi ll the back edge of a ria incised within Miocene limestones and are composed of three main stratal units characterized by distinct sedimentological fe atures. The two lower units, fo rmed by cross bedded sands and laminated days, recorded the development of a small confined beach-barrier depo sitional system, influenced by fr equent high-energy events. The upper unit, represented by chaotic coarser sediments, can be attributed to a destructive marine high-energy event. The physical prop erties of the composing stratal units and the morphological setting of the study area allowed us to reconstruct a suite of storm-and tsunami-related marine depositional processes that might have occurred in recent times along this area of elevated seismicity. In particular, absolute dating and archaeological determinations allow correlating the upper unit to a tsunami wave triggered by the 1693 AD catastrophic earthquake. The same depositional mechanism can also account for some of the coarse levels occurring into the underlying stratal units.

This paper presents an analysis of the vulnerability (AVI Index) and hazard of flooding by sea level rise (FRI Index) in the central Algarve (South Portugal), between the cities of Portimão and Tavira, which is an area of intense urban impact and fast growing tourism. The vulnerability index was calculated using the following parametric thematic maps: lithology, geomorphology, slopes, elevations, distances, bathymetry, variations of the coastline, wave height and activity, variations of sea level and tidal range. The AVI Index was validated by the results obtained from the analysis of the risk of flooding from the FHI Index applied to several time horizons (X 0-present, X 1-100 years, X 2-500 years, X 3-1000 year, X 4-Storm and X 5-Tsunami). Application of GIS and remote sensing techniques, viz. spatial analysis, interpolation processes and geostatistical analysis, permitted a regional forecasting model of change in the mean sea level and the ensuing consequences to be established. Analysis of the obtained results shows an increase in potential flood zones in populous coastal tourist areas with a high risk of exposure and a significant spatial extent of 8.84 km 2 only in Faro municipality. The assessment and delineation of other endangered sectors could contribute to designing appropriate long-term management policies for the coastal of Central Algarve.

No abstract