Maximum Sea Level Research Articles

The evolution of seafloor environmental conditions in the southern Red Sea continental shelf during the last 30 ka

The southern Red Sea is affected by intense interactions between monsoon and sea level changes in a semi-closed environment. Still, the impacts on the wide shelves remain poorly documented. We investigate the seafloor environmental conditions on the southern Red Sea shelf over the last 30 ka through sedimentological (visual inspection, granulometry, bulk density), geochemical (organic carbon, calcium carbonate and nitrogen content) and micropaleontological (benthic foraminifera) observations in a previously dated sediment core (FA09) from the Farasan Islands Archipelago. Glacial sediments exhibit high density and low carbonate contents, whereas post-glacial sediments reflect increased biogenic productivity. Seafloor oxygenation was limited in most of the glacial interval, along with hypersaline conditions. During the maximum sea level lowstand, an enhanced presence of eutrophic-indicator benthic assemblages likely reflects efficient organic matter preservation induced by weak water ventilation. Our proxies combined with a previous surface-water productivity reconstruction reveals a coupling between organic matter flux to the seafloor and surface productivity levels in the southern Red Sea shelf, particularly pronounced during periods of enhanced summer monsoon. This pattern is often accompanied by a decrease in seafloor oxygenation. In contrast, well oxygenated and more oligotrophic seafloor conditions are recorded around the time of Heinrich Stadial 2, when previous work indicates a reduction in summer monsoon intensity and surface productivity levels. A drastic decrease of benthic foraminifera along with increased organic carbon contents in late glacial and late Holocene reflect oxygen-depleted seafloor conditions that we attribute to expansion of an intensified southern Red Sea oxygen minimum zone (OMZ).

Coastal sea levels and wind-waves in the Mediterranean Sea since 1950 from a high-resolution ocean reanalysis

In the Mediterranean Sea, coastal extreme sea levels are mainly caused by storm surges driven by atmospheric pressure and surface winds from extratropical cyclones. In addition, wind-waves generated by the same atmospheric perturbations may also contribute to coastal extremes through wave setup (temporal rise above the mean sea level due to dissipation and breaking of waves in shallow waters close to the shore). This study investigates the spatial and temporal variability of coastal extreme sea levels in the Mediterranean basin, using a new ocean hindcast generated with a coupled hydrodynamic-wave model that simulates storm surges and wind-waves. The numerical simulation covers the period 1950-2021 with high temporal sampling (1h) and at unprecedented spatial resolution for a basin scale analysis, that reaches 200 m along the coastlines. Coastal storm surges and wave heights are validated with available observations (tide gauges, waves buoys and satellites). Comparison against tide gauges shows an average RMSE of 7.5 cm (7.7 cm for extreme events) and mean linear correlation of 0.64 for the whole period. Similarly, comparison of simulated and observed significant wave height shows good agreement, with RMSE lower than 0.25 m and a coefficient correlation as high as 0.95. The results confirm that coastal extreme sea levels are more likely to be located in regions with wide continental shelves favouring the wind contribution to storm surges along with shallow waters that favour wave setup induced by depth-breaking. The contribution of waves to coastal extreme sea levels has been quantified, using the hindcast in combination with an uncoupled simulation and has been shown to be significant, with an assessed wave setup spatial footprint at regional scale and observed maximum sea levels increased by up to 120% in the presence of waves.

Evolution and composition of cliff-top barriers at the northern shore of San Matías Gulf, Patagonia, Argentina

Patagonia is a key place to analyze the climatic trends (waves and winds) of the Southern Hemisphere. The northern coast of the San Matías Gulf (“Bahía Sin fondo” for the original Spanish descriptions) is characterized by an attached sand barrier developed on top of former cliffs. Morphological features are indicating changes in the regional slope when the sea level drowned the depression of the gulf. An original eastern slope was progressively replaced by slopes towards the south. The availability of sand during the transgression and maximum sea level was directed to the east due to the dominant westerly winds. Sand dunes accumulated on top of former cliffs and today –due to coastal erosion-, remain as cliff-top dunes. A conceptual model for the formation of these cliff-top barriers is described in relation to the fluctuation of the sea level and the sand migration, which was studied through mineralogical analysis comparing the different environments: cliff, beach, and dunes. Their composition explains the sediment transport shift and is locally associated to the Río Negro Formation deposits and regionally to Andean Cordillera volcanic sources.

Prediction of the flooding area of the northeastern Caspian Sea from satellite images

Studying the dynamic changes in the coastline of the northeastern Caspian Sea is significant since the level of the Caspian is unstable, and the coastline change can cause enormous damage to the ecology, economy, and population of the coastal part of Kazakhstan. In this work, we use remote sensing and Geographic Information System (GIS) technologies to study the changes in the coastline of the northeastern Caspian Sea and predict the extent of flooding with increasing water levels. The proposed methodology for creating dynamic maps can be used to monitor the coastline and forecast the extent of flooding in the area. As a result of this work, the main factors affecting changes in the coastline were identified. After analyzing the water level data from 1988 to 2019, it was revealed that the rise in water level was observed from 1980 to 1995. The maximum sea level rise was recorded at −26.04 m. After that, the sea level began to fall, and between 1996 and 2009, there were no significant changes; the water level fluctuated with an average of −27.18 m. Then, a map of the water level dynamics in the Caspian Sea from 1988 to 2019 was compiled. According to the dynamics map, water level rise and significant coastal retreat were revealed, especially in the northern part of the Caspian Sea and the northern and southern parts of Sora Kaydak. The method for predicting the estimated flooding area was described. As a result, based on a single map, the flooding area of the northeast coast was predicted. A comparative analysis of Landsat and SRTM data is presented.

Storm Surges Versus Shore Erosion: 21 Years (2000–2020) of Observations on the Świna Gate Sandbar (Southern Baltic Coast)

Abstract Based on observations spanning 21 years (2000–2020), the article studies the effects of storm surges on the shore of the Świna Gate Sandbar in the southern part of the Pomeranian Bay (southern Baltic Sea). Impacts of selected maximum storm surges in each year were assessed with respect to morphological data collected on the beach and the foredune. The data included parameters of beach-dune erosion as measured along a beach transect before and after each surge. Differences and trends in the shore erosion were related to the sea level (SL), duration of a storm surge [highest storm sea level (HSL) > 1 m], wind-wave sector and wave run-up. The relationships were explored using a simple correlation analysis. The most serious erosion was observed during the heaviest surges [HSL > 1.3 m above the mean sea level (AMSL)], with a wave run-up higher than 3.2 m AMSL. Such surges occurred at about 2-year intervals. The average SL during a surge was 1.2 m AMSL, with a run-up of 2.6 m AMSL. The beach and the lower part of the shore, below that level, were eroded each year. The heaviest surges resulted in an average 5.2 m and 7.0 m dune retreat on the high-beach-accumulative shore and on the low-beach-erosive shore, respectively. The dune was not eroded when the beach height exceeded the wave run-up. The heaviest surges eroded away 12–14 m3 of the beach sand volume. The shore erosion was found to be related to the storm surge duration, the maximum SL, the run-up and the beach height prior to the surge.

Technical note: Tail behaviour of the statistical distribution of extreme storm surges

Abstract. The tail behaviour of the statistical distribution of extreme storm surges is conveniently described by a return level plot, consisting of water level (y axis) against average recurrence interval on a logarithmic scale (x axis). An average recurrence interval is often referred to as a “return period”. Hunter's allowance for sea-level rise gives a suggested amount by which to raise coastal defences in order to maintain the current level of flood risk, given an uncertain projection of future mean sea-level rise. The allowance is most readily evaluated by assuming that sea-level annual maxima follow a Gumbel distribution, and the evaluation is awkward if we use a generalized extreme value (GEV) fit. When we use a Gumbel fit, we are effectively assuming that the return level plot is a straight line. In other words, the shape parameter, which describes the curvature of the return level plot, is zero. On the other hand, coastal asset managers may need an estimate of the return period of unprecedented events even under current mean sea levels. For this purpose, curvature of the return level plot is usually accommodated by allowing a non-zero shape parameter whilst extrapolating the return level plot beyond the observations, using some kind of fit to observed extreme values (for example, a GEV fit to annual maxima). This might seem like a conflict: which approach is “correct”? Here I present evidence that the shape parameter varies around the coast of the UK and is consequently not zero. Despite this, I argue that there is no conflict: a suitably constrained non-zero-shape fit is appropriate for extrapolation and a Gumbel fit is appropriate for evaluation of Hunter's allowance.

Mid- to Late Holocene sealevel changes at Abrolhos Archipelago and Bank, southwestern Atlantic, Brazil

This study presents spatiotemporal paleo-sea-level reconstructions from Abrolhos archipelago and Abrolhos Bank, and fill in a coastline gap of 500 km where no precise paleo-sea level reconstruction exists. The reconstructions are based on sedimentary, biological and geomorphological evidences. The data indicates sea-levels up to 2.9 m higher than the current one between the Mid- to Late Holocene, in agreement with the empirical sea-level envelope and with predictions of geophysical sea-level models for the Brazilian coast. The data suggests that there was little, if any, hydroisostatic compensation across 55 km of the continental shelf in the study area, between the archipelago and the mainland coast, given that similar elevations of the post-glacial sea-level maximum exist in both places.

Geological structure and oil and gas potential of Domanik deposits in the central part of the Volga-Ural oil and gas basin

The paper describes the structure and depositional conditions of a domanicoid high-carbon formation (HCF) in the central part of the Volga-Ural oil and gas basin. The structure of the HCF depends on the structural relatedness and paleogeographic conditions of the Late Devonian period, where the time of maximum sea level standing within the basin led to deposition of high organic carbon content intervals. The structural-facies zonation of the HCF distribution area is associated with the zone of relatively deep-water depressions, the zone of slopes, highs and the shallow water shelf with numerous bioherm buildups. The boundaries of the zones were determined by the position of large structural elements of the Tatar and Bashkir arches and depressions of the Kama-Kinel system of troughs. These zones differ not only in the distribution of the thickness of HCF deposits, but also in the nature of the distribution of intervals of the section enriched in organic matter. The maximum number of interlayers enriched by organic matter of the siliceous-carbonate rocks is observed in the section of the Frasnian and Famennian deposits within the central part of the Kama-Kinel system of troughs. Numerous of oil shows from the HCF intervals indicate the potential for further study and spotting of promising areas for hard-to-recover hydrocarbon reserves exploration.

Late-Holocene sea levels from vermetids and barnacles at Ponta do Papagaio, 27° 50′S latitude and a comparison with other sectors of southern Brazil

The height difference between paleo-vermetids and present homologous bioconstructions remains as the best Mid- to Late-Holocene paleo-sea level indicator on the Brazilian coast. The vertical range of the vermetid bioconstructions and, consequently, their precision as a sea-level indicator, varies from ±0.1 to ±1.0 m according to local conditions such as wave energy exposure and tidal range. However, live vermetid bioconstructions are scarce or do not occur at several places south of 23°S latitude, which has led to the use of other bioconstructions (e.g. Phragmatopoma caudata) as a homologous reference level, adding uncertainties to the paleo-sea level reconstructions. At the Southeast Brazilian coast, from 25° 30′ S to 28° 37′ S latitude, the precision varies from ±0.5 to ±1.0 m. At the Ponta do Papagaio headland, at 27°50′38″- 44″ S latitude, the occurrence of the subfossil barnacle Tetraclita stalactifera included in the remains of Holocene vermetids (Petaloconchus varians (d'Orbigny, 1839)) bioconstructions allowed the authors to adopt the living fringe of this barnacle species as a homologous reference level and thereby improve the accuracy of paleo-sea level reconstructions (error margin of only ± 0.5 to ± 0.3 m). The paleo-sea level obtained at Ponta do Papagaio by this method varied between +2.4 and 0.8 m. The resultant relative sea-level curve is included in the empiric sea-level envelop previously determined for the Brazilian coast, south of 28°S latitude, and matches with the far-field eustatic sea-level models. It is also similar to other curves defined for Southern Brazil regions such as Laguna-Imbituba (Santa Marta Cape surroundings, 85-40 km to South from Ponta do Papagaio), São Francisco do Sul (180 km North) and Paraná (220–260 km North). However, the height of 2.4 ± 0.3 m at 4 ky BP at Ponta do Papagaio is similar to the two cited regions to the North, but higher than the one at Laguna-Imbituba for the same period. This difference may not be significant, as it is within the ±1.0 m error margin adopted in the inference of the paleo-sea level at Laguna-Imbituba. If it is significant, it can be attributed to a local lowering of relative sea-level by thermosteric and dynamic effects of the Santa Marta Cape coastal upwelling strengthening at the epoch of maximum sea-level. This work also suggests further quantification of the living vertical distribution of vermetids and other species used as reference species (e.g. Tetraclita stalactifera, Phragmatopoma caudata), under different bedrock morphology, wave exposure and oceanographic conditions, as a necessary way to improve the precision of paleo-sea level reconstructions.

Efficient estimation of partially linear tail index models using B‐splines

SummaryThe tail index is an important parameter in extreme value theory. In this paper, we consider a simple yet flexible spline estimation method for partially linear tail index models. We approximate the unknown function by B‐splines and construct an approximate log‐likelihood function to estimate the coefficients of the linear covariates and the B‐spline basis functions. Consistency and asymptotic normality of the estimators are established. Subsequently, the proposed method is illustrated by using simulations and applications to the Fremantle annual maximum sea levels data and Chicago air pollution data.

Sea-level extremes of meteorological origin in the Red Sea

Severe weather events and the resulting sea-level extremes are considered among the greatest threats to coastal environments. Understanding this coastal hazard is vital for various coastal developments and planning activities. This study examines the sea-level extremes of meteorological origin in the Red Sea. A high-resolution (approximately 500 m) depth-averaged numerical ocean model forced by 5 km dynamically downscaled meteorological fields was implemented to hindcast the sea level of the Red Sea over 37-year, 1980–2016. The model was first validated with observations, showing good agreement with available data. The hindcast model outputs were then analyzed to describe the spatiotemporal features of the sea-level extremes in the Red Sea. The sea-level extremes in the Red Sea developed in response to wind variability over the southern Red Sea and exhibited a basin-wide impact. The magnitudes of the maximum sea levels reached approximately 0.30–0.50 m inside the Red Sea basin, with the highest values (0.85 m) in the Gulf of Suez. The seasonal distribution of the extremes suggests that these are frequent during the winter months (January–March). Assessment of long-term changes in the annual maxima, 99th and 95th percentiles of hourly sea levels indicate no significant trends over the study period.

A yearly maximum sea level simulator and its applications: A Stockholm case study

A yearly maximum sea level simulator for Stockholm is presented. The simulator combines extreme sea level estimates and mean sea level rise projections into a joint probabilistic framework. The framework can be used, for example, to assess the risk that new structures placed at the current minimum allowed height above the sea level can become flooded in the future. Such assessments can be used to underpin future building free levels, which would be a great improvement over the much more arbitrary criteria in use today. Another strong point of the framework is that it can be used to quantify the influence of uncertainties in mean sea level projections, estimates of sea level extremes and future emission scenarios on the risk of flooding. For Stockholm mean sea level uncertainty is found to be much more important than extreme sea level uncertainty. The framework is also set-up to test adaptation measures. It is found that protections that are built once the mean sea level has risen above some given threshold can be very efficient. Lastly, the framework is embedded into a simple decision problem that can be used to calculate risk/reward ratios for land development as a function of height above today’s mean sea level.

Spit-Inlet migration and storm-driven stacking at Praia de Leste Holocene barrier, southern Brazil

The interaction between coastal drift-dependent features, such as spit and inlet systems and the dynamics of estuaries, under the effect of tides, produces significant changes in coastal barriers depositional architecture. Extreme events associated with these autogenic factors insert elements of variability into the depositional architecture of these deposits. OSL (Optically Stimulated Luminescence) dating in the Holocene barrier of Praia de Leste, in the southern region of Brazil, associated with GPR (Ground Penetrating Radar) subsurface surveys and stratigraphic profiles at outcrops, identified a pattern of retrogradational stacking and truncation in the beach ridges, formed by local patterns of erosion and deposition, between the last relative maximum sea level and the beginning of progradation of the Holocene barrier. The predominance of a longshore drift in an opposite direction to the current one between 5.1 ± 0.3 ka and 4.1 ± 0.3 ka is suggested by the migration of spits and the displacement of a paleo-inlet to the southwest, later abandoned during the slow and gradual fall of the relative sea level (RSL) and consequent diminution of the estuary tidal prism.

Pleistocene expansion, anthropogenic pressure and ocean currents: Disentangling the past and ongoing evolutionary history of Patella aspera Röding, 1798 in the archipelago of Madeira

AimsRising sea-level following the Last Glacial Maximum lead to fragmentation of coastal limpet populations between islands of the Archipelago of Madeira. This fragmentation is reinforced by recent heavy exploitation reducing effective population size on Madeira Island. We use the limpet P. aspera to understand how the role of processes at different time scales (i.e. changes in the sea level and overexploitation) can influence the genetic composition of an extant species, relating these processes to reproductive phenology and seasonal shifts in ocean currents. LocationMadeira Island, Porto Santo and Desertas (Archipelago of Madeira, NE Atlantic Ocean). TaxonThe limpet Patella aspera. MethodsTwelve microsatellite genetic markers were used. A power analysis was used to evaluate the power of the microsatellite markers to detect a signal of population differentiation. Long-term past migrations were assessed using a Bayesian Markov Montecarlo approach in the software MIGRATE-n to estimate mutation-scaled migration rates (M = m/μ; m, probability of a lineage immigrating per generation; μ, mutation rate). Two scenarios were evaluated using an Approximate Bayesian Computation (ABC) in the software DIYABC 2.1 (i) Scenario 1: considered a population scenario from a reduced Ne at time t3 to a higher Ne at time t2; and (ii) Scenario 2 considering a reduction of Ne from a time t3 to a time t2. ResultsColonization of the archipelago by Portuguese settlers six centuries ago probably led to an important decrease in the genetic diversity of the species (Ne). Contemporary gene flow strongly support a pattern of high asymmetric connectivity explained by the reproductive phenology of the species and spatio-temporal seasonal changes in the ocean currents. Spatio-temporal reconstructions using Bayesian methods, including coalescent and Approximate Bayesian Computation (ABC) approaches, suggest changes in the migration patterns from highly symmetric to highly asymmetric connectivity with subtle population differentiation as consequence of post-glacial maximum sea level rise during the Holocene. Main conclusionsOur results suggest that anthropogenic activity could have had serious effects on the genetic diversity of heavily exploited littoral species since the end of the Pleistocene, probably accelerating in recent years.

Flood frequency analysis with the GEV distribution for r-annual events

Floods are the maximum annual flows of a river and their frequency analysis are statistical techniques that allow estimating values associated with low probabilities of being exceeded. Such predictions allow the hydrological design and review of hydraulic works. The fundamental stage of frequency analysis is the selection and fit, to the available data or sample, of a probability distribution function to make predictions. The generalized extreme value (GEV) distribution has theoretical bases that make it a probabilistic model suitable for floods, maximum sea levels, extreme wind speeds, etc. Due to its genesis, the GEV processes one data per year, the maximum. This disadvantage has been overcome with the method of the r annual maximum events. Such procedure is described and applied to the adjustment of the GEV function, through the maximum likelihood method, using the Complex algorithm of multiple restricted variables, for numerical maximization. Five records of floods with five events per year were integrated from hydrometric stations of the Hydrological Region No. 10 (Sinaloa), Mexico. Also, two records of maximum sea levels with r = 5 were processed, taken from specialized literature; one of them is non-stationary since it shows a trend. Results were analyzed and the predictions of the GEV adjustment with r annual events, were compared against those of the classical methods of moments L and LH. Finally, conclusions are formulated, which highlight the convenience of the described method and point out the advantages of using the Complex algorithm as a numerical technique; due to the above, the systematic application of the described procedure is recommended.

Early and middle Miocene paleobathymetry of the Vienna Basin (Austria)

The Vienna Basin (VB) originated during the early Miocene and represents one of the largest onshore oil and gas field in Europe. The VB is composed of several horst and graben structures forming different subbasins, each with its own geodynamic evolution and deviating paleobathymetric developments during the Miocene. We present an analysis of water depth evolution along a NE-SW transect by applying a transfer function for benthic foraminifers. We document dramatic changes in the depth profile through time, which coincide with shifts of prevailing tectonic regimes. Bathyal conditions were established during the early Miocene piggy-back stage and the early middle Miocene extensional phase. A clear shallowing trend from upper bathyal to inner neritic conditions occurred during the middle Miocene extensional tectonic phase.All lowstand systems of relative sea level in the VB coincide with global Mi-events. The observed maxima of the relative sea level in the VB are vaguely in phase with the global record from the Ottnangian (late early Miocene) to the middle Badenian (middle Miocene) but exceed the range of global sea level rise by three to four times, suggesting a strong tectonic amplification. Fluctuations of the relative sea level during the late Badenian and Sarmatian (Serravallian, middle Miocene) range well within the global signal, documenting ceasing influence of tectonics.

Climate Change Implications Found in Winter Extreme Sea Level Height Records around Korea

The impact of climatic variability in atmospheric conditions on coastal environments accompanies adjustments in both the frequency and intensity of coastal storm surge events. The top winter season daily maximum sea level height events at 20 tidal stations around South Korea were examined to assess such impact of winter extratropical cyclone variability. As the investigation focusses on the most extreme sea level events, the impact of climate change is found to be invisible. It is revealed that the measures of extreme sea level events—frequency and intensity—do not correlate with the local sea surface temperature anomalies. Meanwhile, the frequency of winter extreme events exhibits a clear association with the concurrent climatic indices. It was determined that the annual frequency of the all-time top 5% winter daily maximum sea level events significantly and positively correlates with the NINO3.4 and Pacific Decadal Oscillation (PDO) indices at the majority of the 20 tidal stations. Hence, this indicates an increase in extreme event frequency and intensity, despite localized temperature cooling. This contradicts the expectation of increases in local extreme sea level events due to thermal expansion and global climate change. During El Nino, it is suggested that northward shifts of winter storm tracks associated with El Nino occur, disturbing the sea level around Korea more often. The current dominance of interannual storm track shifts, due to climate variability, over the impact of slow rise on the winter extreme sea level events, implies that coastal extreme sea level events will change through changes in the mechanical drivers rather than thermal expansion. The major storm tracks are predicted to continue shifting northward. The winter extreme sea level events in the midlatitude coastal region might not go through a monotonic change. They are expected to occur more often and more intensively in the near future, but might not continue doing so when northward shifting storm tracks move away from the marginal seas around Korea, as is predicted by the end of the century.

Long-term Trend Analysis of Extreme Coastal Sea Levels with Changepoint Detection

Abstract Sea level rise can bring disastrous outcomes to people living in coastal regions by increasing flood risk or inducing stronger storm surges. We study long-term linear trends in monthly maximum sea levels by applying extreme value methods. The monthly maximum sea levels are extracted from multiple tide gauges around the coastal regions of the world over a period of as long as 169 years. Due to instrument changes, location changes, earthquakes, land reclamation, dredging, etc., the sea level data could contain inhomogeneous shifts in their means, which can substantially impact trend estimates if ignored. To rigorously quantify the long-term linear trends and return levels for the monthly maximum sea level data, we use a genetic algorithm to estimate the number and times of changepoints in the data. As strong periodicity and temporal correlation are pertinent to the data, bootstrap techniques are used to obtain more realistic confidence intervals to the estimated trends and return levels. We find that the consideration of changepoints changed the estimated linear trends of 89 tide gauges (approximately 30% of tide gauges considered) by more than 20cmcentury-1. Our results are summarized in maps with estimated extreme sea level trends and 50-year return levels.

Otsenki amplitudnykh kharakteristik nakata voln tsunami na razlichnykh uchastkakh Chernomorskogo poberezh'ya

This paper is devoted to computational modelling of tsunami wave propagation and runup to the shore for some points on the Russian, Turkish, Bulgarian and Ukrainian coasts of the Black Sea. The nonlinear long wave model was used to solve the problem of wave propagation from hydrodynamic tsunami sources, which can constitute the greatest potential danger for the studied coast areas. The hydrodynamic sources were set in the form of an elliptical elevation, the parameters of which were chosen according to the sea level response to an underwater earthquake of magnitude 7. All the sources were located in seismically active areas, where tsunamigenic earthquakes had already occurred, along the 1500 m isobath. Near each of the studied points in the area above 300 m depths, we calculated marigrams, i.e. time-series of sea level fluctuations caused by the passage of waves. Then, a one-dimensional problem of tsunami propagation and run-up on the coast was solved for each of the points under study, where the obtained marigrams were used as boundary conditions. Peculiarities of tsunami wave propagation have been shown depending on the bottom and land relief in the studied areas of the Black Sea. Estimates have been obtained of the sea level maximum rise and fall during surge and subsequent coastal drainage for the characteristic scales of relief irregularity at different points. For possible tsunamigenic earthquakes, the largest splashes may occur in the region of Yalta (2.15 m), Cide (1.9 m), Sevastopol (1.4 m), and Anapa (1.4 m). Tsunami propagation in the Feodosiya and Varna coastal areas is qualitatively similar, with maximum wave heights of 0.64 m and 0.46 m, respectively. The coastlines of Evpatoriya (0.33 m) and Odessa (0.26 m) are least affected by tsunami waves due to the extended shelf.

Submarine Geomorphology of the Southwestern Sardinian Continental Shelf (Mediterranean Sea): Insights into the Last Glacial Maximum Sea-Level Changes and Related Environments

During the lowstand sea-level phase of the Last Glacial Maximum (LGM), a large part of the current Mediterranean continental shelf emerged. Erosional and depositional processes shaped the coastal strips, while inland areas were affected by aeolian and fluvial processes. Evidence of both the lowstand phase and the subsequent phases of eustatic sea level rise can be observed on the continental shelf of Sardinia (Italy), including submerged palaeo-shorelines and landforms, and indicators of relict coastal palaeo-environments. This paper shows the results of a high-resolution survey on the continental shelf off San Pietro Island (southwestern Sardinia). Multisensor and multiscale data—obtained by means of seismic sparker, sub-bottom profiler chirp, multibeam, side scan sonar, diving, and uncrewed aerial vehicles—made it possible to reconstruct the morphological features shaped during the LGM at depths between 125 and 135 m. In particular, tectonic controlled palaeo-cliffs affected by landslides, the mouth of a deep palaeo-valley fossilized by marine sediments and a palaeo-lagoon containing a peri-littoral thanatocenosis (18,983 ± 268 cal BP) were detected. The Younger Dryas palaeo-shorelines were reconstructed, highlighted by a very well preserved beachrock. The coastal paleo-landscape with lagoon-barrier systems and retro-littoral dunes frequented by the Mesolithic populations was reconstructed.