scholarly journals Ancient Coastal Changes Due to Ground Movements and Human Interventions in the Roman Portus Julius (Pozzuoli Gulf, Italy): Results from Photogrammetric and Direct Surveys

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 658 ◽  
Author(s):  
Pietro P. C. Aucelli ◽  
Gaia Mattei ◽  
Claudia Caporizzo ◽  
Aldo Cinque ◽  
Salvatore Troisi ◽  
...  
Keyword(s):  
Sea Level ◽  
3D Model ◽  
First Century ◽  
Structural Elements ◽  
Sea Levels ◽  
Ground Movements ◽  
Vertical Ground ◽  
Coastal Changes ◽  
Fish Tank ◽  
The Military

This research aims to evaluate the amount of vertical ground movements during Roman times inside the archaeological area of Portus Julius (Gulf of Pozzuoli) using high-precision surveys on the most reliable archaeological sea-level markers. Measuring the submersion of ancient floors, structural elements belonging to a former fish tank, and several roman pilae, two different relative sea levels (RSLs), related to the beginning and the end of the first century BCE, respectively, −4.7/−5.20 m and −3.10 m MSL (mean sea level), were detected. A photogrammetric survey was carried out in order to produce a 3D model of the fish tank. The results in terms of the RSL variations have enabled us to reconstruct a morpho-evolution of the ancient coastal sector during the last 2.1 kyBP. At the beginning of the first century BCE, the area was characterized by a sheltered gulf with numerous maritime villae located along the coast. In 37 BCE, the construction of the military harbour of Portus Julius strongly modified the paleogeography of the sector, which was also affected by a prevailing subsidence at least until the end of the first century BCE (year 12 BCE), when the port was converted into a commercial hub.

scholarly journals Twenty-first century response of Petermann Glacier, northwest Greenland to ice shelf loss

2020 ◽  
pp. 1-11
Author(s):  
Emily A. Hill ◽  
G. Hilmar Gudmundsson ◽  
J. Rachel Carr ◽  
Chris R. Stokes ◽  
Helen M. King
Keyword(s):  
Sea Level ◽  
First Century ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Sea Levels ◽  
Grounding Line ◽  
Global Mean Sea Level ◽  
Near Future ◽  
Global Mean ◽  
Large Sections

Abstract Ice shelves restrain flow from the Greenland and Antarctic ice sheets. Climate-ocean warming could force thinning or collapse of floating ice shelves and subsequently accelerate flow, increase ice discharge and raise global mean sea levels. Petermann Glacier (PG), northwest Greenland, recently lost large sections of its ice shelf, but its response to total ice shelf loss in the future remains uncertain. Here, we use the ice flow model Úa to assess the sensitivity of PG to changes in ice shelf extent, and to estimate the resultant loss of grounded ice and contribution to sea level rise. Our results have shown that under several scenarios of ice shelf thinning and retreat, removal of the shelf will not contribute substantially to global mean sea level (<1 mm). We hypothesize that grounded ice loss was limited by the stabilization of the grounding line at a topographic high ~12 km inland of its current grounding line position. Further inland, the likelihood of a narrow fjord that slopes seawards suggests that PG is likely to remain insensitive to terminus changes in the near future.

Holocene relative sea levels and coastal changes in the lower Cree valley and estuary, SW Scotland, U.K.

2002 ◽  
Vol 93 (4) ◽  
pp. 301-331 ◽  
Author(s):  
D. E. Smith ◽  
J. M. Wells ◽  
T. M. Mighall ◽  
R. A. Cullingford ◽  
L. K. Holloway ◽  
...  
Keyword(s):  
Sea Level ◽  
Early Holocene ◽  
Coastal Geomorphology ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Sea Levels ◽  
Coastal Changes

ABSTRACTChanges in Holocene (Flandrian) relative sea levels and coastal geomorphology in the lower Cree valley and estuary, SW Scotland, are inferred from detailed morphological and stratigraphical investigations. A graph of relative sea level changes is proposed for the area. Rising relative sea levels during the early Holocene were interrupted at c. 8300–8600 14C years B.P.(c. 9400–9900 calibrated years B.P.), when an extensive estuarine surface was reached at c. −1 m O.D., after which a fluctuating rise culminated at c. 6100–6500 14C B.P. (c. 7000–7500 calibrated years B.P.) in a prominent shoreline and associated estuarine surface measured at 7·7–10·3 m O.D. A subsequent fall in relative sea level was followed by a rise to a shoreline at 7·8–10·1 m O.D., exceeding or reoccupying the earlier shoreline over much of the area after c. 5000 14C B.P. (c. 5,800 calibrated years B.P.), before relative sea level fell to a later shoreline, reached after c. 2900 14C B.P. (c. 3100 calibrated years B.P.) at 5·5–8·0 m O.D., following which relative sea levels fell, ultimately reaching present levels. During these changes, a particular feature of the coastline was the development of a number of barrier systems. The relative sea level changes identified are compared with changes elsewhere in SW Scotland and their wider context is briefly considered.

scholarly journals Timescales of emergence of chronic flooding in the major economic center of Guadeloupe

2021 ◽  
Vol 21 (2) ◽  
pp. 703-722
Author(s):  
Gonéri Le Cozannet ◽  
Déborah Idier ◽  
Marcello de Michele ◽  
Yoann Legendre ◽  
Manuel Moisan ◽  
...  
Keyword(s):  
Sea Level ◽  
Tide Gauge ◽  
Ground Motions ◽  
Weather Conditions ◽  
Coastal Zones ◽  
Tide Gauge Records ◽  
Sea Levels ◽  
Vertical Ground Motions ◽  
Vertical Ground ◽  
Flooding Events

Abstract. Sea-level rise due to anthropogenic climate change is projected not only to exacerbate extreme events such as cyclones and storms but also to cause more frequent chronic flooding occurring at high tides under calm weather conditions. Chronic flooding occasionally takes place today in the low-lying areas of the Petit Cul-de-sac marin (Guadeloupe, West Indies, French Antilles). This area includes critical industrial and harbor and major economic infrastructures for the islands. As sea level rises, concerns are growing regarding the possibility of repeated chronic flooding events, which would alter the operations at these critical coastal infrastructures without appropriate adaptation. Here, we use information on past and future sea levels, vertical ground motion, and tides to assess times of emergence of chronic flooding in the Petit Cul-de-sac marin. For RCP8.5 (Representative Concentration Pathway 8.5; i.e., continued growth of greenhouse gas emissions), the number of flood days is projected to increase rapidly after the emergence of the process so that coastal sites will be flooded 180 d a year within 2 decades of the onset of chronic flooding. For coastal locations with the lowest altitude, we show that the reconstructed number of floods is consistent with observations known from a previous survey. Vertical ground motions are a key source of uncertainty in our projections. Yet, our satellite interferometric synthetic-aperture radar results show that the local variability in this subsidence is smaller than the uncertainties in the technique, which we estimate to be between 1 (standard deviation of measurements) and 5 mm/yr (upper theoretical bound). Despite these uncertainties, our results imply that adaptation pathways considering a rapid increase in recurrent chronic flooding are required for the critical port and industrial and commercial center of Guadeloupe. Similar processes are expected to take place in many low-elevation coastal zones worldwide, including on other tropical islands. The method used in this study can be applied to other locations, provided tide gauge records and local knowledge of vertical ground motions are available. We argue that identifying times of emergence of chronic flooding events is urgently needed in most low-lying coastal areas, because adaptation requires decades to be implemented, whereas chronic flooding hazards can worsen drastically within years of the first event being observed.

scholarly journals Some Pitfalls of the Semiempirical Method Used to Project Sea Level

2015 ◽  
Vol 28 (9) ◽  
pp. 3779-3785 ◽  
Author(s):  
Mirko Orlić ◽  
Zoran Pasarić
Keyword(s):  
Sea Level ◽  
Transfer Functions ◽  
Response Times ◽  
Semiempirical Method ◽  
First Century ◽  
Third Century ◽  
Sea Levels ◽  
Level Data ◽  
Related Response ◽  
Twenty First Century

Abstract Three variants of the semiempirical method for sea level projection are considered. They differ in assuming that the response of sea level to temperature forcing is equilibrium, inertial, or a combination of the two. All variants produce a successful regression of the temperature and sea level data, albeit with controlling parameters that differ among the cases. The related response times vary considerably, with a realistic value (~50 yr) obtained only if both the equilibrium and the inertial dynamics are taken into account. A comparison of sea levels projected by using the three variants shows that the time series are similar through the middle of the twenty-first century but they radically diverge by the end of the twenty-third century. This result is interpreted with the aid of the underlying transfer functions. It suggests that one should be cautious when using the semiempirical method to project sea level beyond the twenty-first century.

scholarly journals Archaeological and Natural Indicators of Sea-Level and Coastal Changes: The Case Study of the Caesarea Roman Harbor

Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 306
Author(s):  
Ehud Galili ◽  
Amos Salamon ◽  
Gil Gambash ◽  
Dov Zviely
Keyword(s):  
Sea Level ◽  
Active Fault ◽  
Supporting Evidence ◽  
Western Basin ◽  
Winter Storms ◽  
Sea Levels ◽  
Natural Processes ◽  
Sediment Deposits ◽  
Unconsolidated Sand ◽  
Coastal Changes

Archaeological and geomorphological features, as well as traces left by tsunamis, earthquakes, and vertical earth-crust displacements, are used to identify sea-level and coastal changes. Such features may be displaced, submerged or eroded by natural processes and human activities. Thus, identifying ancient sea levels and coastal changes associated with such processes may be controversial and often leads to misinterpretations. We exemplify the use of sediment deposits and sea-level and coastline indicators by discussing the enigmatic demise of the Roman harbor of Caesarea, one of the greatest marine constructions built in antiquity, which is still debated and not fully understood. It was suggested that the harbor destruction was mainly the result of either tectonic subsidence associated with a local, active fault line, or as a result of an earthquake/tsunami that struck the harbor. Here we examine and reassess the deterioration of the harbor in light of historical records, and geological, geomorphological and archaeological studies of natural and man-made features associated with the harbor. We show that the alleged evidence of an earthquakes or tsunami-driven damage to the outer breakwaters is equivocal. There is no supporting evidence for the assumed tectonic, active fault, nor is there a reliable historic account of such a catastrophic destruction. It is suggested that geo-technic failure of the breakwater’s foundations caused by a series of annual winter storms was the main reason for the destruction and ultimate collapse of the western basin of the harbor. The breakwaters were constructed on unconsolidated sand that was later washed away by storm waves and sea currents that frequently hit the Israeli coast and undercut the breakwaters. The pounding effect of the waves could have contributed to the destruction by scouring and liquefying the sandy seabed underlying the foundations. Tsunamis that may have hit Caesarea could have added to the deterioration of the breakwaters, but did not constitute the main cause of its destruction.

scholarly journals Economic damages from Hurricane Sandy attributable to sea level rise caused by anthropogenic climate change

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Benjamin H. Strauss ◽  
Philip M. Orton ◽  
Klaus Bittermann ◽  
Maya K. Buchanan ◽  
Daniel M. Gilford ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
East Coast ◽  
The United States ◽  
Hurricane Sandy ◽  
Water Levels ◽  
Anthropogenic Climate Change ◽  
Economic Damage ◽  
Sea Levels

AbstractIn 2012, Hurricane Sandy hit the East Coast of the United States, creating widespread coastal flooding and over $60 billion in reported economic damage. The potential influence of climate change on the storm itself has been debated, but sea level rise driven by anthropogenic climate change more clearly contributed to damages. To quantify this effect, here we simulate water levels and damage both as they occurred and as they would have occurred across a range of lower sea levels corresponding to different estimates of attributable sea level rise. We find that approximately $8.1B ($4.7B–$14.0B, 5th–95th percentiles) of Sandy’s damages are attributable to climate-mediated anthropogenic sea level rise, as is extension of the flood area to affect 71 (40–131) thousand additional people. The same general approach demonstrated here may be applied to impact assessments for other past and future coastal storms.

Records of sea-level highstand over the Meghalayan age/late Holocene from uranium-series ages of beachrock in Weizhou Island, northern South China Sea

The Holocene ◽  
2021 ◽  
pp. 095968362110332
Author(s):  
Tingli Yan ◽  
Kefu Yu ◽  
Rui Wang ◽  
Wenhui Liu ◽  
Leilei Jiang
Keyword(s):  
South China Sea ◽  
Sea Level ◽  
South China ◽  
Intertidal Zone ◽  
Meteoric Water ◽  
Northern South China Sea ◽  
Water Environment ◽  
Sea Levels ◽  
China Sea ◽  
Micro Structures

Beachrock is considered a good archive for past sea-levels because of its unique formation position (intertidal zone). To evaluate sea-level history in the northern South China Sea, three well-preserved beachrock outcrops (Beigang, Gongshanbei, and Hengling) at Weizhou Island, northern South China Sea were selected to examine their relative elevation, sedimentological, mineralogical, and geochemical characteristics. Acropora branches with well-preserved surface micro-structures were selected from the beachrocks and used to determine the ages of these beachrocks via U-series dating. The results show that the beachrocks are composed of coral reef sediments, terrigenous clastics, volcanic clastics, and various calcite cements. These sediments accumulated in the intertidal zone of Weizhou Island were then cemented in a meteoric water environment. The U-series ages of beachrocks from Beigang, Gongshanbei, and Hengling are 1712–768 ca. BP, 1766–1070 ca. BP, and 1493–604 ca. BP (before 1950 AD) respectively. Their elevations are 0.91–1.16 m, 0.95–1.24 m, and 0.82–1.17 m higher than the modern homologous sedimentary zones, respectively. Therefore, we concluded that the sea-level in the Meghalayan age (1766–604 ca. BP) was 0.82–1.24 m higher than the present, and that the sea-level over this period showed a declining trend.

scholarly journals Flooding Conditions at Aveiro Port (Portugal) within the Framework of Projected Climate Change

2021 ◽  
Vol 9 (6) ◽  
pp. 595
Author(s):  
Américo Soares Ribeiro ◽  
Carina Lurdes Lopes ◽  
Magda Catarina Sousa ◽  
Moncho Gomez-Gesteira ◽  
João Miguel Dias
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Climate Change Impacts ◽  
Storm Surges ◽  
Historical Period ◽  
Return Periods ◽  
Wave Regime ◽  
Mean Sea Level ◽  
Sea Levels ◽  
Far Future

Ports constitute a significant influence in the economic activity in coastal areas through operations and infrastructures to facilitate land and maritime transport of cargo. Ports are located in a multi-dimensional environment facing ocean and river hazards. Higher warming scenarios indicate Europe’s ports will be exposed to higher risk due to the increase in extreme sea levels (ESL), a combination of the mean sea level, tide, and storm surge. Located on the west Iberia Peninsula, the Aveiro Port is located in a coastal lagoon exposed to ocean and river flows, contributing to higher flood risk. This study aims to assess the flood extent for Aveiro Port for historical (1979–2005), near future (2026–2045), and far future (2081–2099) periods scenarios considering different return periods (10, 25, and 100-year) for the flood drivers, through numerical simulations of the ESL, wave regime, and riverine flows simultaneously. Spatial maps considering the flood extent and calculated area show that most of the port infrastructures' resilience to flooding is found under the historical period, with some marginal floods. Under climate change impacts, the port flood extent gradually increases for higher return periods, where most of the terminals are at high risk of being flooded for the far-future period, whose contribution is primarily due to mean sea-level rise and storm surges.

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