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Submarine-mass-failure-generated tsunamis pose a significant threat to the coastal communities around the Corinth Gulf. An effort was made towards the mitigation of a potential tsunami generated in the eastern part of the gulf, due to a submarine landslide. The impact of the tsunami was assessed along the coastal segment of the summer resort town of Xylocastro. The analysis (study) of the data within a Geographical Information System revealed that a 4 m tsunami run-up will flood 12% of the town's district. One fifth of the permanent residents are expected to be affected, while one fourth of the infrastructure is likely to undergo damages. Although alarm and reaction times to a possible local tsunami are short, there is just enough time for evacuation. Therefore a more detailed hazard assessment and an emergency management plan should be undertaken, not only for Xylocastro, but also for other coastal regions in the Corinth Gulf, where extensive development is taking place. [ABSTRACT FROM AUTHOR]

Examination of seismic profiles west of Milos Island (Aegean Sea) show that the north Milos slope is affected by extensive mass movements, whereas the south slope is generally stable. Conditions that promote sediment failures include late Quaternary volcanic activity and related seismic activity, tectonically oversteepened slopes and possibly hydrothermal fluid escape. Big and small depressions indicative of phreatic explosions and hydrothermal venting, respectively, have been observed in Milos shelf. Sediment coring revealed that the surficial sediments are relatively soft and thus prone to failure. The lack or presence of sapropel layers is also indicative of unstable or stable slope conditions of the surficial sedimentary cover, respectively. [ABSTRACT FROM AUTHOR]

Seismic data have been used to evaluate the extent, characteristics and importance of the sediment failures in the Santorini basin. The failures are small but abundant, occupying almost half of the areal extent of the study area, and modify the relief of the basin and the surrounding slopes. The fact that surficial mass flow deposits are the source area of younger sediment failures is evident of the high intensity and frequency of the sediment instabilities. The major factors which are responsible for the observed instabilities are seismic activity and seismicity related to modern volcanic activity, steep slopes and the open sediment structure due to the specific texture of the volcanic material. Sediment failures are believed to compose a big part of the deeper sedimentary column. [ABSTRACT FROM AUTHOR]

A detailed marine survey in Antikyra Bay in the northern margin of the Gulf of Corinth graben in Greece was carried out to examine the distribution and dispersion of bauxitic "red mud" tailings. The red mud tailings have been discharged at a rate of 500 000 to 640 000 tonnes/year via submerged outfalls on the shelf at a water depth of 100 m. The red mud tailings at the mouth of the outfalls have formed three oval shaped mounds. These mounds have a maximum thickness of about 27 m and thin out radially in the downslope direction along the longitudinal axis of the bay in a south-southwestward direction forming a common depositional lobe. The "red mud" tailings are transported by turbidity currents, via channels which incise the slope, to the basin floor at a water depth of 800 m and over a distance of 17 km, where they form small sheet-like deposits. High-resolution sedimentological analysis of 30 short cores using visual inspection, Xradiography, grain size measurements, X-ray diffraction and smear slides have shown the presence of seven (7) distinct turbidity flow events which were activated on the shelf and the slope and have occurred during the 24 years of tailing discharge. Five of these have their source at the "red-mud" mounds at the mouths of the outfalls and two of them have their source at the shelf break and the upper slope. The analysis revealed that the former consist of (a) graded structureless red mud deposits and/or bioturbated red mud deposits, or (b) laminated red mud deposits, whereas the latter are mostly structureless and poorly graded. [ABSTRACT FROM AUTHOR]

A very high-resolution shallow-seismic survey along the central part of the faultbounded Corinth Gulf southern margin (offshore Xylocastro town) revealed that three morphological zones characterize the area: the shelf, the slope and the basin. Three E-W trending, right stepping basin bounding faults define the basin-slope contact, producing a step like configuration along the base of slope. Steep scarps, caused by mass failures, sculpt the fault plane surfaces, which act as part of the slope. The shelf and the slope are dissected by submarine canyons and numerous minor channels. The largest canyons are located immediately off the river mouths, run perpendicular to the slope and are linear. Seismic profiles across the canyons suggest that some of them are fault controlled. The head and the walls of the canyons are affected by mass failures. It is estimated that about 1.1 km3 of mass failed sediments have been removed from the canyons and transported downslope to the basin floor. [ABSTRACT FROM AUTHOR]