Sea level Research

The Atlantic Coast of southwestern Namibia is renowned for its Pliocene to Holocene diamondiferous deposits, which contributed more than 63 million carats of diamonds to the global market. A continuum of fossil shoreline deposits associated with barriers to linear and pocket beaches stretches over circa 110 km in length. Of these, the most highly economic are the fossil linear and pocket beach deposits that are preserved over highly competent Proterozoic bedrock. Potholes and gullies, the prominent bedrock-trapsite features, have controlled diamond concentration. By contrast, the barrier shorelines that developed on unconsolidated fluvial and marine sediments at a palaeo-river mouth are less productive. Here, trapsites are absent and diamond accumulation and retention occurred via interstitial trapping in a coarse gravel framework under highly energetic littoral settings. It therefore follows that diamond enrichment is governed by the sedimentological characteristics of the gravel allied to the dynamics of their depositional environments. We examine the relationship of diamond enrichment with the littoral processes at an environmental and subenvironmental level of a latest Pliocene/earliest Pliocene gravel barrier beach complex (BBC). Results show variability in both diamond concentrations and sizes across the barrier that commensurate with a diversity of morpho-sedimentary dynamics. The study, a first of its kind, provides insights into the diamond enrichment of a BBC. It demonstrates how detailed sedimentological reconstruction of the barrier environments can improve the exploration efficacy of such diamond-bearing littoral placers.

As part of an investigation of the long-term effects of ditch-draining on peat deposits, we cored peat samples altogether from 51 peatland sites that had been earlier inventoried by volumetric coring by the Geological Survey of Finland (GTK) during the 1980s. In most cases, it proved possible to match the old and new profiles cored of the same site, especially concerning their lower parts, in which typically no big changes seem to have taken place. However, comparison of the results revealed a recurring, albeit not systematic bias: the dry bulk density values of the GTK data tended to be somewhat smaller than our corresponding results. In cases where peat compression can be ruled out, a plausible explanation is that the piston corer did not function properly. This paper describes a test series in which we compared the GTK piston corer, a 1-m box corer and a Russian peat corer in quantitative sampling of peat strata. The piston corer proved to have a slight tendency to underperform, particularly with peats rich in sedge, cottongrass or wood remains. Implications of the variable sampler performance on quantitative peat inventories are discussed.

In the book, Restless Tides of Time, Sea-Level Change: Past, Present and Prescient, Bilal Haq invites readers on a sweeping odyssey across Earth's watery epochs, a narrative distilled from decades of research, weaving scientific exactitude with story-teller's flair. From the primeval watery stirrings of the Precambrian to the Anthropocene's rapidly shifting shorelines, he breathes life into our planet's continuously transformational relationship with its oceans. Haq unravels the forces – tectonic, climatic, and cosmic – that sculpted coastlines and drowned continents through time, showing us not only how we measure the oceans' pulse, but what it tells us about our past and also our future. Engaging both specialists and general readers, this book reveals the deep interdependence between humanity and the oceans. In eleven chapters, Haq explores how our understanding of the oceans has grown – from early observations in the Age of Reason to today and beyond. Restless Tides of Time is both a story of Earth's ever-evolving, malleable oceans and a reminder that our own fate is inextricably bound to the movement of the tides.

Bilal U. Haq – geoscientist, naturalist, and poet – has dedicated his research to uncovering the deep rhythms of the oceans, tracing the dramatic rise and fall of sea levels across the Phanerozoic Eon, and understanding the powerful forces that have shaped our planet's highly mutable land-and sea-scapes. A member of the European Academy of Sciences, Haq is a laureate of the Prestwich Prize conferred by Société Géologique de France, and a recipient of Geological Society of America's International Distinguished Career Award. These accolades recognized not only the extensive scope of his scientific contributions –encompassing vast temporal and geographic scales – but also his sustained commitment to communicating the dynamic history of Earth's oceans, a critical component of the planet's geological narrative, to both scientific and broader audiences.

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The Gulf of Gabès is situated in the south eastern part of the Tunisian coasts, characterized by its semiarid climate and low topographies with extensive wetlands. Several studies aiming at the knowledge and the reconstruction of the paleoenvironments and the evolution of the human presence were conducted in the past. However, relating to the evolution during Late Holocene these studies were generally limited to a narrow coastal fringe and mainly emphasized by a geological approach. These studies focused primarily on sea-level variations. This paper is based on a methodology considering both geomorphological and archaeological data. It takes into account the sea as an essential morphogenic agent but, at the same time, considers the continental and structural factors. The use of archaeological data makes it possible to appreciate the impact of these factors. It also helps to a better understanding of the evolution of human societies and the ways in which they adapted to their environment. During the Holocene, it appears that despite local variations, alluvial plains and wetlands, have experienced each of them two periods leading to their extension. For the alluvial plains, the favorable episodes took place in the presence of the Neolithic people and under the eyes of the Romans and after their leaving. For wetlands, the favorable episodes coincided with two periods characterized by sea-level rise. The first was witnessed by the Neolithic populations. The second was recorded after the Antiquity and is continuing today. Over the course of this history and depending on whether the trend has been towards sea-level rise or the arrival of large quantities of alluvium to the coast, the wetlands have extended or been reduced or erased. This evolution has impacted man behavior and explains his choice for certain locations today materialized by archaeological remains.

The morphology of beach ridge plains along active margins can be used to reconstruct coastal subsidence during large megathrust earthquakes. Here we use satellite imagery and automatic level surveys to reconstruct the build-up of a new beach ridge along a 10 km long stretch of the western Acehnese coast after the complete destruction of the beach during the great Sumatra -Andaman earthquake and successive tsunami in December 2004. The western Acehnese coast is characterized by ridge and swale topography reflecting the long-term progradation of the coastline. Radiocarbon dates obtained from marshy deposits in between ridges indicate an average progradation rate of 1.3e1.8 m per year over the last 1000 years. As a result of coseismic subsidence of 0.5e1 m and tsunami inundation in 2004, the most seaward beach ridge was destroyed and the coastline receded on average 110 m landward representing 65e85 years of average progradation. However, by 2006 a new 22 m wide ridge had formed. In the following years the coast prograded by an additional 30 m, but has not yet recovered to its pre-December 2004 position. In addition to the spatial data, topographic surveys conducted in 2009, 2012 and 2013 indicate that the crest of the newly formed beach ridge is 0.8e1.3 m higher than the crests of older beach ridges further inland. The source material for the new ridge is most likely sand transported seaward by the back flow of the 2004 tsunami and stored on the upper shoreface. In the months and years after the tsunami, this sediment is reworked by regular coastal processes and transported back to shore, leading to the reconstruction of a higher beach ridge in equilibrium with the vertical displacement of the coast and the resulting higher relative sea level. The preservation potential of the newly formed ridge depends on sediment availability within the coastal system to balance coastal profile adjustments due to rapid postseismic uplift. In Aceh, the preservation of seismically modified beach ridge morphology seems likely and another prominent ridge can be found in 640 m distance to the shoreline. It most likely formed in the aftermath of a previous megathrust earthquake and tsunami about 600 years ago matching sediment and coral records for this region.

We report initial results from our recent field survey documenting the inundation and resultant deposits of the 2011 Tohoku-oki tsunami from Sendai Plain, Japan. The tsunami inundated up to 4.5 km inland but the > 0.5 cm-thick sand deposit extended only 2.8 km (62% of the inundation distance). The deposit however continued as a mud layer to the inundation limit. The mud deposit contained high concentrations of water-leachable chloride and we conclude that geochemical markers and microfossil data may prove to be useful in identifying the maximum inundation limit of paleotsunamis that could extend well beyond any preserved sand layer. Our newly acquired data on the 2011 event suggest that previous estimates of paleotsunamis (e.g. 869 AD Jōgan earthquake and tsunami) in this area have probably been underestimated. If the 2011 and 869 AD events are indeed comparable, the risk from these natural hazards in Japan is much greater than previously recognized.

Shorelines have always been hubs of human activity and development meaning much of our cultural heritage is concentrated in coastal settings. In recent decades, changing environmental conditions and the effects of global warming (i.e., shoreline erosion, sea-level rise, land subsistence) threaten to destroy much of our remaining global coastal heritage. To prevent the further loss of archaeological contexts, this study seeks to develop a coastal vulnerability index through geospatial analysis to assess the vulnerability of 35 precontact shell midden sites along the Nansemond River in Suffolk, Virginia. The Nansemond middens offer a long-term history of how coastal inhabitants interacted with their surrounding landscape, with occupation of the area ranging from the Early Archaic period through European contact. This research considers various environmental and cultural variables used to determine which archaeological sites are most threatened by environmental changes and have the greatest potential to contribute valuable data to understand the past.

In January 2004 a Mediterranean cyclone in the Aegean Sea seriously affected the north coast of Samos Island, damaged the harbour mole of a coastal village, and catapulted its building material along with heavy boulders to the inner harbour basin.

Ma rse ille ve yre Ma ssi f Be c de l'A igl e No rd Ca rry le Ro ue t Ma rs ei lle La Ci ot at Ca pe Mo rg iou Ca ssi s Rio u Ca p Ca na ille Ni olo n Fr iou l Ca lan qu e Po rt Mi ou Po rt-Pin Ca lan qu e Ca lan qu e de Mo rg iou Ca lan qu e de So rm iou Pla ne Ja rre Ma ïre

À chacun son paysage Dès avant les croisades, l'argent et l'azur furent les couleurs de la cité phocéenne, couleurs d'un monde transparent, magique, qui a poussé jusqu'ici de grands navigateurs venus du Levant pour les envoyer ensuite au-delà des portes d'Hercule. Une nouvelle quête les passionne de façon plus récente : explorer le fond des mers.

Earthquakes have certainly always fascinated and frightened man since prehistory; their normal manifestation can cause civilian casualties and considerable economic damage (Sumatra, 2005). However, generally, when a submarine earthquake occurs, with a magnitude over 7 on Richter scale, it can cause a tsunami. In case of vulnerability, this phenomenon can provoke great damage (Japan, 2011). That is why numerous researchers were conducted to understand the physical characteristics of tsunami wave and the sedimentological features of their deposits. This work aims to diagnostic and analyzes the evidence used by the authors to identify the high energetic deposits along the Atlantic coast of Morocco and the Iberian Peninsula, to determine if they are related to a tsunamigenic earthquake. In fact, along this coastal zone, numerous studies were established to distinguish high energetic deposits, attributed to storms or tsunamis. Most of those studies were based on calcarenite boulder's accumulation (Whelan and Kelletat, 2005; M'hammdi and al. 2008). Nevertheless, those accumulations alone cannot be considered as strong evidence for tsunami's occurrence. If the imbrication and the orientation of the boulders is a good criterion for tracing tsunamis origins, these boulders could have returned from their initial position during storms, posterior to a tsunami that might have deposed them (Harhoura) or may simply result from falling rocks resulting from erosion of the coastal cliff (Rabat, Temara, and on the Tangier coast.). It is therefore recommended to compare the accumulation and disposition of these boulders with other sedimentological signatures, such as the distribution of heavy minerals (El Talibi and al., 2016), exoscopic analysis (Bruzzi and Prone, 2000) and AMS (Magnetic Susceptibility Anisotropy) in order to reconstruct the sites affected by the manifestation of ancient tsunamis, in the perspectives to limit the risks caused by this hazard.

The ancient settlement complex with harbour and fish ponds in Fizine in the western part of Portorose Bay is one of the most interesting archaeological sites on the Slovenian coast in northwestern Istria on the upper Adriatic. The area was inhabited at least from the last decades of the Roman Republic (second half of the 1st century BC) to the early Middle Ages (6th/7th century AD), thanks to its naturally sheltered position from north winds. This paper reviews the results and findings of archaeological research since 1963, focusing on the finds from the 2017, 2018, and 2021 underwater interventions.
The underwater architecture on the nearshore part of the seabed was recognised as a facility for breeding and/or keeping marine animals (vivarium) with landing piers. Remains on the walls of the extensive jetty forming two enclosed basins are reliable indicators of the relative rise in sea level from the beginning of the 1st century AD, when the building was constructed, to the present day, estimated at 1.5 m ± 20 cm. The presumed fish farm and associated shoreline facilities were probably in use until the 5th century.
Recent underwater trial excavations in the western part of the bay revealed a stone fill combined with horizontal logs and wooden piles that probably served as a breakwater. Special attention is given to the finds of a yard or spar of a spritsail and a masthead with integral pulley, both of which were reused as mooring piles, as well as discarded pieces of ship rigging and fishing gear. The AMS dating of the wooden elements and the pottery from the associated deposits attests to the use of the harbour between the 3rd and 4th/5th centuries.

I, Megan Gomes, declare that this thesis is my own, unaided work, except where referenced and otherwise acknowledged. This thesis is submitted in fulfilment of the requirements for the degree of Master of Science at the University of the Witwatersrand, Johannesburg. I have not submitted this work for examination at any other university.

Przedstawione w niniejszym artykule wyniki sll ~s szerszych badati nad genezll, i mineralogill kaolinow pizolitowych. Wykorzystano w nich probki pocho~ce z roi:nych regionow Afryki, Ameryki P6hlocnej oraz Buropy. W pracy zwr6cono r6wniei: uwag~ na sklad izotop6w tlenu i wodoru ~l!Cych wai:nym zrodlem informacji w rozwai:aniach nt genezy skal ilastych. Badaniami obj~to prom. skal ilastych (ok. 2,5 m mi~ szosci) pochodzl!Cych z rejonu zwanego Central Wadi K.alabsha, leZ~go okolo 100 km SW od Asuanu (ryc. 1). Probki skal pobrane zostaly z naturalnych odsloni~ oraz staryeh wyrobisk gorniczyeh. W stropie profjJu wystwuje pokrywa drobnoziarnistego piaskowca i:elazistego barwy wiSniowej, ponii:ej ktorej lei:ll kaoliny zawierajlf,Ce makroskopowe widoczne pizoidy (ryc. 2). Intensywnosc zabarwienia kaolinow zmniejsza si~ ku sPllgowi profilu prze-1 ~ 21"vv~ 3D 4fS1 5* Rye. J. LokaJizacja obsZQI'U badmi na tie uproszezonej mapy geologicznej (9)

2018: Belkhayat, Z., N. Mhammdi, A. Trakadas, L. Huff & F. Medina, New observations of tsunami deposits along the Loukkos estuary; possible evidence for the AD 1755 Lisbon tsunami. In P.P. Cunha, J. Dias, H. Veríssimo, L. V. Duarte, P. Dinis, F.C. Lopes, A.F. Bessa & J.A. Carmo (eds), Atas do IX Simpósio sobre a Margem Ibérica Atlântica, Coimbra, Portugal. Departamento de Ciências da Terra da Universidade de Coimbra: Coimbra: 209-210.

Terrestrial heat flux was measured in fjords, in boreholes, and in offshore wells at sites across the convergent margin of southwestern British Columbia from the continental shelf landward to the Garibaldi Volcanic Belt. Temperatures in the offshore wells were corrected for drilling disturbances, and formation thermal conductivities were modeled using measurements on cuttings and downhole geophysical logs. Marine measurements in the fjords were corrected for the large effects of refraction as well as aperiodic temperature variations in the bottom waters. There was excellent agreement between marine measurements and those from nearby onshore boreholes. The heat flux above the subducting Juan de Fuca plate steadily decreases landward from over 50 mW m−2 on the shelf to 25 mW m−2 seaward of the Garibaldi Volcanic Belt. An abrupt increase to 80 mW m−2 over a distance of 20 km is centered 30 km seaward of the volcanic zone. Very large variations in heat flux occur locally within the Plei...

We review the status of current sea-level observing systems with a focus on the coastal zone. Tide gauges are the major source of coastal sea-level observations monitoring most of the world coastlines, although with limited extent in Africa and part of South America. The longest tide gauge records, however, are unevenly distributed and mostly concentrated along the European and North American coasts. Tide gauges measure relative sea level but the monitoring of vertical land motion through highprecision GNSS, despite being essential to disentangle land and ocean contributions in tide gauge records, is only available in a limited number of stations (25% of tide gauges have a GNSS station at less than 10 km). Other data sources are new in-situ observing systems fostered by recent progress in GNSS data processing (e.g. GPS reflectometry, GNSS-towed platforms) and coastal altimetry currently measuring sea level as close as 5 km from the coastline. Understanding observed coastal sea level also requires information on various contributing processes, and we provide an overview of some other relevant observing systems, including those on (offshore and coastal) wind-waves and water density and mass changes.

In 1755 CE, a strong earthquake followed by a transatlantic tsunami destroyed large coastal areas; it also left its sedimentary imprints in the Boca do Rio valley (western Algarve, Portugal). This tsunami layer is very well preserved and has been analysed in several studies. Deposits of preceding extreme wave events, however, have rarely been described for the entire Algarve coast. In this study, we present a multiproxy analysis of seven sediment cores from the Boca do Rio region, organized in two crossing transects, one parallel and the other perpendicular to the coastline. The geochronological framework has been established by combining radiocarbon and optically stimulated luminescence dating with sedimentological and geochemical analyses (XRF, C/N, magnetic susceptibility, granulometry, micropalaeontology), and covers the palaeogeographical evolution of that area for the last four millennia. As expected, the 1755 CE tsunami was easily identified at all coring sites, as a sandwiched stratum between fine-grained alluvium. This event layer presents several tsunami characteristics, such as erosive basal contact, rip-up clasts, a fining-upward sequence, and a mud cap. At one coring site, a second extreme wave event layer of marine origin was detected within floodplain deposits, due to its granulometric, XRF, magnetic susceptibility and micropalaeontological properties. It is stratigraphically located below the 1755 CE Lisbon tsunami layer and can be associated with another yet undocumented extreme wave event, most likely dating to the mid or late 1st millennium CE.

Panjang Island Reef Flat is a remote area on Berau Continental Shelf with pristine ecological conditions. This site was selected to study the nature of sediment dynamics in tropical shallow waters. In addition, the sediment textural parameters provide good proxies for long term hydrodynamic process within the marine ecosystem. The aims of this study were to determine: (1) sediment textural parameters; (2) the transport mechanism of sediment particles; and (3) the depositional environment characteristics of the Panjang Island reef flat. The grain size parameters were further analysed to reveal the transport mechanism and energy regime. The results show the presence of coarse to fine sand sediments transported predominantly by rolling and suspension, with a sedimentary environment classified as Inner Shelf. These findings imply the incidence of gradual hydrodynamic energy attenuation at the shelf edge, characterized by breaking waves, followed by extensive seagrasses bed; these are co...

This assessment of ecology and diversity of Diatoms in Kuttanadu, is continuation of the previous publications of Green-algae and Blue-green-algae of the same region; all the three investigations were carried out simultaneously. The unique Kuttanadu wetlands (90°17'N to 90°40'N; 760°19'E to 760°33'E), a well known ‘Rice bowl’ of Kerala, spread over 53,639 hectares, is located in Alapuzha District of Kerala, India. This wetland was once known for its high biodiversity, but currently severely affected by intensive green-revolution activities of past few decades. Main objective of the present report is to explain the diversity and ecological status of Diatoms in relation to the environment conditions currently existing in the region. Duration of the study was from December 2009 to October 2010. Soil samples of three different soil-types in two different crop-seasons, at two diverse crop-growth-stages are analyzed and compared. Altogether 120 composite soil samples rando...

This study investigates the relative sea-level changes and the influence of vertical land movements at South Western Tropical Pacific Islands. The dataset consists of tide gauge records, remote satellite altimetry observations and GPS records. After evaluating the uncertainties and the nature of vertical land movements, we focus on the present and future relative sea-level changes. The main source of uncertainty comes from the types of vertical land motion estimates. Results revealed that the relative sea level has increased more than the global mean sea level (from 0.8 to 4.2 mm yr-1 higher) overall in the region during the last 4-6 decades, especially at the islands located over the most tectonically active areas where future changes cannot be reliably projected. For most of the islands located outside tectonically active areas, relative sea-level projected changes by the end of the 21st century are of similar magnitude to the projected global mean sea-level (0.6 ± 0.2 m in the RCP 8.5 scenario), with the exception of Tahiti where major changes are projected (0.8 ± 0.2 m).

Widespread deposition of pelagic-hemipelagic sediments provide an archive for the Late Cretaceous greenhouse that triggered sea level oscillations. Global distribution of dinoflagellate cysts (dinocysts) exhibited a comparable pattern to the eustatic sea level, and thus, considered reliable indicators for sea level and sequence stratigraphic reconstructions. Highly diverse assemblage of marine palynomorphs along with elemental proxies that relate to carbonates and siliciclastics and bulk carbonate δ13C and δ18O from the Upper Cretaceous Abu Roash A Member were used to reconstruct short-term sea level oscillations in the Abu Gharadig Basin, southern Tethys. Additionally, we investigated the relationship between various palynological, elemental, and isotope geochemistry parameters and their response to sea level changes and examined the link between these sea level changes and Late Cretaceous climate. This multiproxy approach revealed that a long-term sea-level rise, interrupted by mi...

To understand the geological sources of magnetic anomalies two petrophysical mapping programmes were carried out in Finland. The first provided more than 100 000 samples of bulk density, magnetic susceptibility and intensity of remanence. In the other c. 6000 minidrill samples were analyzed by direction of remanent magnetization in addition to the previous. Finally, to tie the measurement with the

Over the past decades, substantial progress has been made in tsunami research. Be that as it may, little is still known about tsunami deposits and their related depositional mechanisms in coastal areas in historical and archaeological contexts. In particular, the Phoenician, Greek and Roman trade and military networks along the Mediterranean and Atlantic coasts, with their cities, harbours

The present study area is located within the south–eastern segment of the Baltic Sea framed by 55o30’–56o30’ N and 19o00’–21o15’E. The area is re-visited with the aim to describe in more detail the geologic prerequisite and development of the palaeo–incisions as well as the timing of their subsequent infillings. The channels form distinctive features in the sedimentary bedrock along the outer limits of pre–Weichselian ice sheets, on average reaching depths into the bedrock of 50 m in the nearshore zone of Lithuania to 100 m along the slope to the Gotland depression in the west. The development of palaeo–incisions systems is governed by the easily eroded late Palaeozoic to Mesozoic bedrock of the present area. Only rare ocurrences of channels have been reported from the middle and lower parts of the Palaeozoic further west in the Baltic Sea. The present investigation supports a mechanism that the channels formed below the ice near the ice sheet margin by melt water erosion under high...

In this paper, cross-shore morphodynamic evolution of a sand and sand-gravel composite beach, are compared and contrasted used historic surveys of beach profiles. The differential behavior of cross-shore morphodynamics at a range of time scales covering event-scale dynamics up to intra-annual scale variability are investigated and discussed. The application of equilibrium concept to both beach types is explored through Dean’s equilibrium profile and Vellinga’s beach erosion profile. Variability of cross-shore profile dynamics are quantified and discussed through bulk statistical analysis. Multi-scale morphodynamic trends are determined using Empirical Orthogonal Eigenfunction (EOF) analysis. The above analysis enables to recognise failure mechanism of each beach type during a storm.

Fine-grained sediments in southern Finland were deposited during the retreat of the continental Fennoscandian ice-sheet at around 13,000 cal BP, leaving subsequent ice-contact deposits and postglacial lake and, finally, the modern brackish water Baltic Sea basin (BSB). As a result of the strong glacioisostatic land uplift of the region, these sediments today lie above sea-level in coastal Finland. The recent expansion of cities to locations where superficial sediments are more challenging for construction purposes has increased the need for comprehensive understanding of the properties and geometry of these fine-grained superficial deposits. Commonly used site-specific lithostratigraphical characteristics of clayey deposits run the risk of ambiguous correlation between sites because of different types of postglacial depositional settings. The present study applies an allostratigraphical approach to classify late-and postglacial clayey deposits using examples from four sedimentary basins in the vicinity of the city of Espoo along the southern coast of Finland. This entails a reinterpretation of 17 core logs collected during the period 2006-2009 and reported in earlier studies, combined with examination of five new cores collected in 2016 coupled with borehole measurements of resistivity-temperature and electrical resistivity tomography (ERT). Physical proxies and sediment characteristics demonstrate that grey postglacial lacustrine silty (Ancylus Lake) clay is truncated at the top by an undulating erosional surface (unconformity), which is covered by a silt to sand layer a few centimetres thick that has a gradual-bioturbated upper contact to the greenish-grey brackish water (Litorina Sea) mud. Sediments above and below the unconformity are intensely bioturbated, and black mottling of Fe-monosulphide is observed in the brackish water mud. Evidently, this unconformity is of high engineering-geological significance because the organic-rich brackish water mud has a poorer bearing capacity and higher abundance of sulphide minerals that form sulphuric acid upon oxidation. It is demonstrated that this unconformity is spatially well recognised and provides a key stratigraphic marker for wider and more accurate comparison between sites with fine-grained deposits in the Helsinki metropolitan area and potentially in other urban areas in the northern Baltic Sea region.

The 2004 Indian Ocean tsunami and the 2011 Tōhoku earthquake and tsunami caused large-scale topographic changes in coastal areas. Whereas much research has focused on coastlines that have or had large human populations, little focus has been paid to coastlines that have little or no infrastructure. The importance of examining erosional and depositional mechanisms of tsunami events lies in the rapid reorganization that coastlines must undertake immediately after an event. A thorough understanding of the pre-event conditions is paramount to understanding the natural reconstruction of the coastal environment. This study examines the location of sediment erosion and deposition during the 2004 Indian Ocean tsunami event on the relatively pristine Phra Thong Island, Thailand. Coupled with satellite imagery, we use numerical simulations and sediment transportation models to determine the locations of significant erosion and the areas where much of that sediment was redeposited during the tsunami inundation and backwash processes. Our modeling approach suggests that beaches located in two regions on Phra Thong Island were significantly eroded by the 2004 tsunami, predominantly during the backwash phase of the first and largest wave to strike the island. Although 2004 tsunami deposits are found on the island, we demonstrate that most of the sediment was deposited in the shallow coastal area, facilitating quick recovery of the beach when normal coastal processes resumed.

While there is evidence for an acceleration in global mean sea level (MSL) since the 1960s, its detection at local levels has been hampered by the considerable influence of natural variability on the rate of MSL change. Here we report a MSL acceleration in tide gauge records along the U.S. Southeast and Gulf coasts that has led to rates (>10 mm yr −1 since 2010) that are unprecedented in at least 120 years. We show that this acceleration is primarily induced by an ocean dynamic signal exceeding the externally forced response from historical climate model simulations. However, when the simulated forced response is removed from observations, the residuals are neither historically unprecedented nor inconsistent with internal variability in simulations. A large fraction of the residuals is consistent with wind driven Rossby waves in the tropical North Atlantic. This indicates that this ongoing acceleration represents the compounding effects of external forcing and internal climate variability.

In their comment, England and Walker (2015) consider a subset of shoreline observations presented in Shi et al. (2015) to argue the position that the shoreline is essentially horizontal (4593.9 ± 0.75 m at one standard deviation or 4593.9 ± 1.5 m at two standard deviations). Then they follow their previous analysis (England et al., 2013) to make the case that the absence of deflection of shorelines from the horizontal places a lower bound on the elastic strength of the crust and the viscosity of the deep crust. Although we do not disagree with their previous model to assess crustal strength, we argue that it has been misapplied in this case. We appreciate the opportunity to clarify and amplify our contention that one must consider the full distribution of data. Particularly, observations from the "tails" of the histogram of shoreline elevation are critical to the determination of crustal strength and cannot be discounted simply because they fall outside a chosen range from the mean. We argue that analyzing the variation in shoreline

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

Climate change has led to increased sea levels, which are caused by a complex interplay of the physical environment components from coastal areas, causing the rise in storm surge, erosion and flooding. In this scenario, the low-lying topography of the Mumbai region is highly susceptible to sea level-induced flooding and coastal erosion due to the increasing number of economic activities. The unsustainable urbanization, unplanned development, and huge land conversion lead to the destruction of this region lead to the destruction of mangroves and filled waterways with construction debris which makes the region more vulnerable to flooding due to inadequate drainage, overflow and absence of natural protectors. These human-induced factors and their impacts remain unknown. Therefore, the study uses four socioeconomic variables (CVI4) with five geological (CVI5) and three geological variables (CVI8; with integrating CVI5) to assess the role of developmental and socio-economic activities in overall coastal vulnerability (CVI12) analysis. To quantify the importance of the combined variables and understand the response, random forest (RF) model was also used. This study selected four different iterations with integrating the pixel-based differentially weighted rank values of all variables to determine the significant causes behind that have an impact on coastal vulnerability index (CVI). The results show that CVI5 and CVI8 contributed 7.8% and 36.9%, respectively, whereas CVI4 contributed 55.3% to the CVI12. The response curve shows that the influence of these variables is an increasing trend to CVI12 and the results of CVI12 are highly correlated with socioeconomic index variables (r = 0.84, p = 0.001) which indicates the socio-economic variables played a major role towards the coastal vulnerability of the region. It suggests that unsustainable urbanization, unplanned development and coastal erosion increasing pressure make Mumbai and Kurla region more vulnerable to flood. Accordingly, CVI12 results show 55.83 km of the shoreline surveyed, being very low vulnerable, a moderate vulnerability of 60.91 km, while a high vulnerability of 50.75 km is considered to be very high. The results may be used as a guide in formulating policies to mitigate and adjust the Mumbai coast as the rise in sea level is expected to cause more frequent coastal floods, etc.

A basin-scale record of high-frequency transgressive-regressive (T-R) fluctuations of Turonian age in the Bohemian Cretaceous Basin, Central Europe, has previously been interpreted as being significantly influenced by short-term eustasy. Here, nearshore siliciclastic strata in two separate sub-basins are correlated to a multi-stratigraphic dataset from a new research core (Bch-1) drilled in offshore marine sediments of the central basin. A high-resolution d 13 C org record from Bch-1 is presented along with major-and minor-element proxies, TOC, carbonate contents, terrestrial to marine palynomorph ratios, and detailed macro-and microfossil biostratigraphy. The 400 m thick Turonian through Lower Coniacian interval permits correlation to the highest-resolution C-isotope curves available: all carbonisotope events demonstrated by d 13 C carb studies in the British Chalk, NW Germany and other reference sections in Europe are recognised in the d 13 C org curve from Bch-1. A number of short-term, basin-wide regressions in the Bohemian Cretaceous Basin show a recurrence interval of 100 kyr or less. This is an order of magnitude shorter than the timing of sea-level falls inferred from the New Jersey margin and the Apulian platform, interpreted to having been driven by glacioeustacy. The small magnitude of the Bohemian Basin sea-level falls, typically < 40 m, indicates that the 2.4 Myr period suggested by others to generate 3 rd

A morpho-geophysical investigation of two beaches in Thailand over the last decade shows that they have completely recovered from the 2004 Indian Ocean tsunami (IOT) without any human intervention. Although the beach systems show contrasting styles of recovery in both cases natural processes have reconstructed the beaches to comparable pre-tsunami morphologies in under a decade, demonstrating the existence of punctuated equilibrium in coastal systems and the resilience of natural systems to catastrophic events. Through a combination of remote sensing, field surveys and shallow geophysics we reconstruct the post-event recovery of beaches at Phra Thong Island, a remote, near pristine site that was severely impacted by the IOT. We identify periods of aggradation, progradation and washover sedimentation that match with local events including a storm in November 2007. The rapid recovery of these systems implies that majority of sediment scoured by the tsunami was not transported far offshore but remained in the littoral zone within reach of fair-weather waves that returned it (the sediment) to the beach naturally.

The coast between Tanabe and Kushimoto, on the west part of the Kii peninsula, was hit by huge tsunamis accompanied with an earthquake belonging to the gigantic Nankai earthquake. Many stone monuments are arranged on this coast for the victims of the 1946 Showa Nankai earthquake-Tsunami. In the Edo period (1602 to 1868 AD) two huge earthquakes were generated; one is the Hoei earthquake of 1707, and the other is the Ansei Nankai earthquake of 1854. Hatori(1980) made a field survey for estimating tsunami heights of those earthquake but his result was a rough estimation of the heights of historical earthquakes. In this study we made database of tsunami damage records on the basis of old documents which were introduced on the material books of the historical earthquakes published by Musha(1941, and 1951), and by Earthquake Research Institute (1983,1987,1989, and 1994). We conducted a field survey in the period from 17 to 20 January, 2017. The left figure shows the tsunami height distrib...

A major challenge for managing impacts and implementing effective mitigation measures and adaptation strategies for coastal zones affected by future sea level (SL) rise is our limited capacity to predict SL change at the coast on relevant spatial and temporal scales. Predicting coastal SL requires the ability to monitor and simulate a multitude of physical processes affecting SL, from local effects of wind waves and river runoff to

The accumulation of data sets of past tsunamis is the most basic but reliable way to prepare for future tsunamis because the frequency of tsunami occurrence and their magnitude can be estimated by historical records of tsunamis. Investigation of tsunami deposits preserved in geological layers is an effective measure to understand ancient tsunamis that occurred before historical records began. However, the areas containing tsunami deposits can be narrower than the area of tsunami inundation, thus resulting in underestimation of the magnitude of past tsunamis. A field survey was conducted after the 2010 Chile tsunami and 2011 Japan tsunami to investigate the chemical properties of the tsunami-inundated soil to examine the applicability of tsunami inundation surveys considering water-soluble salts in soil. The soil and tsunami deposits collected in the tsunami-inundated areas are rich in water-soluble ions (Na ? , Mg 2? , Cl-, Brand SO 4 2-) compared with the samples collected in the non-inundated areas. The analytical result that the ratios of Na ? , Mg 2? , Brand SO 4 2to Clare nearly the same in the tsunami deposits and in the tsunamiinundated soil suggests that the deposition of these ions resulting from the tsunami inundation does not depend on whether or not tsunami deposits exist. Discriminant analysis of the tsunami-inundated areas using the ion contents shows the high applicability of these ions to the detection of tsunami inundation during periods when the amount of rainfall is limited. To examine the applicability of this method to palaeotsunamis, the continuous monitoring of water-soluble ions in tsunami-inundated soil is needed as a future study.

Here we present a new way to automatically classify the exact sub-environment of deposition of sediment from estuarine sediment cores. It can be challenging to define the exact sub-environment of deposition in core as sediment of a given appearance, or facies, can be found in multiple settings. This issue is important given that petrophysical, geomechanical and reservoir quality properties of sedimentary rocks are typically strongly influenced by the specific sub-environment of deposition. Here, using a tenfold classification of depositional sub-environments, we have determined the subenvironments of 482 sample sites from the Ravenglass Estuary, in NW England, UK. We then analysed Page 2 the textural characteristics of each of these samples using laser particle size analysis. A novel automatic textural classification scheme was then developed using a combination of visual discrimination of gravel and vegetated surfaces, principal component analysis and recursive portioning routine (RPART) in Rstudio. The new automatic textural classification scheme can resolve eight of the ten sub-environments of deposition: gravel beds, salt-marsh, mud flat, mixed flat, sand flat, tidal inlet, combined south foreshore/ebb tidal delta and combined tidal inlet/north foreshore. Our scheme cannot differentiate the spatially adjacent tidal inlet and north foreshore sediments as they are texturally identical. Similarly, the scheme cannot differentiate the spatially adjacent ebb tidal delta and southern foreshore sediments as they also are texturally identical. We have applied our surface-calibrated method to a 3 m Holocene core drilled through fine-grained surface sandflats into interbedded fine-and coarse-grained sands in the Ravenglass Estuary and successfully defined palaeoenvironments of deposition. Our automatic approach to the definition of palaeo-environment of deposition approach supersedes a simple lithofacies-based approach for the Ravenglass Holocene core as we can define, cm-by-cm, how the exact estuarine sub-environments evolved over the last 10,000 years. This approach could also be applied to other modern estuaries and could be trialled for use with ancient and deeply buried sedimentary rocks deposited in equivalent marginal marine estuarine environment.