Sea-Level Reconstructions and Archaeological Indicators: A Case Study from the Submerged Hellenistic Harbor at Akko, Israel

2021 ◽  
Author(s):  
Alyssa Victoria Pietraszek ◽  
Oded Katz ◽  
Jacob Sharvit ◽  
Beverly Goodman-Tchernov
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Sea Level Change ◽  
Relative Sea Level ◽  
Factors Affecting ◽  
Sea Levels ◽  
Level Change ◽  
Structural Deterioration ◽  
Short And Long Term

<p>With the impending threat of continued sea-level rise and coastal inundation, it is important to understand the short- and long-term factors affecting sea-level in a particular region. Such a feat can be accomplished by turning to indicators of past sea-levels. This study aims to highlight the utility of archaeological indicators in sea-level reconstructions, using Akko on Israel’s northern Mediterranean micro-tidal coast as a case study. Here, installations belonging to the maritime metropolis’ Hellenistic Period (3rd to 1st centuries BCE) harbor, which have well-constrained chronological and elevational limitations, were identified at depths averaging 1.1 to 1.2 meters below present sea-level (mbpsl). These features would have been located sub-aerially during the time of their construction and use, indicating a change in relative sea-level in the area since this time. Utilizing a multiple proxy approach incorporating marine sedimentological and geoarchaeological methodologies with previously recorded regional data, three possible explanations for this apparent sea-level change were assessed: structural deterioration, sea-level rise, and vertical tectonic movements. This study revealed that, although signs of structural deterioration are apparent in some parts of the quay, this particular harbor installation is well-established as in situ as it has a continuous upper surface and its southern edge is built directly on the underlying bedrock. Consequently, the harbor’s current submarine position can instead be attributed to sea-level change and/or vertical tectonic displacements. While this amount of sea-level rise (over 1 m) is in agreement with glacio-hydro-eustatic values suggested for other areas of the Mediterranean, it falls below those previously reported locally. In addition, most studies suggest that the tectonic movement along this stretch of coastline is negligible. These new data provide a reliable relative sea-level marker with very little error with regard to maximum sea-level, thereby renewing the overall consideration of the tectonic and sea-level processes that have been active along this stretch of coastline during the last 2,500 years.</p>

Inception of a global atlas of Holocene sea levels

2020 ◽  
Author(s):  
Nicole Khan ◽  
Erica Ashe ◽  
Robert Kopp ◽  
Ben Horton ◽  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Working Group ◽  
Research Priorities ◽  
Sea Level Change ◽  
Relative Sea Level ◽  
Sea Level Variability ◽  
Sea Levels ◽  
The Holocene ◽  
Level Change

<p>Determining the rates, mechanisms and geographic variability of sea-level change is a priority science question for the next decade of ocean research. To address these research priorities, the HOLocene SEA-level variability (HOLSEA) working group is developing the first standardized global synthesis of Holocene relative sea-level data to: (1) estimate the magnitudes and rates of global mean sea-level change during the Holocene; and (2) identify trends in spatial variability and decipher the processes responsible for geographic differences in relative sea-level change.</p><p>Here we present the efforts of the working group to compile the database, which includes over 12,000 sea-level index points and limiting data from a range of different indicators across seven continents from the Last Glacial Maximum to present. We follow a standard protocol that incorporates full consideration of vertical and temporal uncertainty for each sea-level index point, including uncertainties associated with the relationship of each indicator to past sea-level and the methods used to date each indicator. We highlight important challenges overcome to aggregate the standardized global synthesis, and discuss those that still remain. Finally. we apply a spatio-temporal empirical hierarchical statistical model to the database to estimate global sea-level variability and spatial patterns in relative sea level and its rates of change, and consider their driving mechanisms. Long-term, this effort will enhance predictions of 21st century sea-level rise, and provide a vital contribution to the assessment of natural hazards with respect to sea-level rise.</p>

scholarly journals Historical and recent sea level rise and land subsidence in Marina di Ravenna, northern Italy

2016 ◽  
Vol 59 (5) ◽  
Author(s):  
Ines Cerenzia ◽  
Davide Putero ◽  
Flavio Bonsignore ◽  
Gaia Galassi ◽  
Marco Olivieri ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Land Subsidence ◽  
Adriatic Sea ◽  
Sea Level Change ◽  
Northern Adriatic Sea ◽  
Relative Sea Level ◽  
Northern Adriatic ◽  
Level Change ◽  
Rate Of Increase

The regions facing the northern Adriatic Sea are particularly vulnerable to sea-level rise. Several trade ports are located there, and the area is important from social and economical viewpoints. Since tourism and cultural heritage are a significant source of income, an increase in sea-level could hinder the development of these regions. One of the longest sea-level time series in the northern Adriatic, which goes back to the late 1880s, has been recorded at Marina di Ravenna, in Emilia-Romagna region. The record is anomalous, showing a rate of increase that largely exceeds that observed in nearby stations. During the last few decades, geodetic campaigns based on geometric high precision leveling, SAR interferometry, and GPS have monitored the Ravenna area. In this work, tide gauge observations are merged with yet unpublished geodetic data, aiming at a coherent interpretation of vertical land movements. We confirm that land subsidence is the major cause of relative sea-level change at Marina di Ravenna, at least during the period allowing  for a quantitative analysis (1990-2011). The rate of absolute sea-level change (2.2±1.3 mm yr−1 during the same time period), given by the difference between the rate of relative sea-level change and the rate of subsidence, is consistent with the rate of absolute sea-level change observed by altimetry in the northern Adriatic Sea.

scholarly journals Challenges in relative sea-level change assessment highlighted through a case study: The central coast of Atlantic Patagonia

2019 ◽  
Vol 182 ◽  
pp. 103008
Author(s):  
Marta Pappalardo ◽  
Carlo Baroni ◽  
Monica Bini ◽  
Ilaria Isola ◽  
Adriano Ribolini ◽  
...  
Keyword(s):  
Sea Level ◽  
Sea Level Change ◽  
Central Coast ◽  
Relative Sea Level ◽  
Change Assessment ◽  
Level Change

scholarly journals RELATIVE SEA LEVEL CHANGE ALONG THE BLACK SEA COAST FROM TIDE-GAUGE OBSERVATIONS

2019 ◽  
Vol XLII-3/W8 ◽  
pp. 43-47 ◽  
Author(s):  
N. B. Avsar ◽  
S. H. Kutoglu
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Black Sea ◽  
Tide Gauge ◽  
Sea Level Change ◽  
The Black Sea ◽  
Relative Sea Level ◽  
Level Change ◽  
Black Sea Coast ◽  
Gauge Station

<p><strong>Abstract.</strong> Potential sea level rise poses a significant threat to low-lying areas. Considering present and future of coastal areas, scientific study of sea level rise is an essential for adapting to sea level extremes. In this study, the relative sea level change in the Black Sea were investigated using data of 12 tide-gauge and 6 GNSS stations. Results generally indicated sea level rise along the Black Sea coast. Only at Bourgas tide-gauge station, a sea level fall was detected. A significant sea level change were not determined at Sinop tide-gauge station. On the other hand, at some stations such as Poti and Sile, ground subsidence contribution to relative sea level changes were observed.</p>

scholarly journals On the geophysical processes impacting palaeo-sea-level observations

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yusuke Yokoyama ◽  
Anthony Purcell
Keyword(s):  
Sea Level ◽  
Large Scale ◽  
Global Climate ◽  
Sea Level Change ◽  
Sea Level Changes ◽  
Factors Affecting ◽  
Ice Volume ◽  
Level Change ◽  
Recent Developments ◽  
Geophysical Processes

AbstractPast sea-level change represents the large-scale state of global climate, reflecting the waxing and waning of global ice sheets and the corresponding effect on ocean volume. Recent developments in sampling and analytical methods enable us to more precisely reconstruct past sea-level changes using geological indicators dated by radiometric methods. However, ice-volume changes alone cannot wholly account for these observations of local, relative sea-level change because of various geophysical factors including glacio-hydro-isostatic adjustments (GIA). The mechanisms behind GIA cannot be ignored when reconstructing global ice volume, yet they remain poorly understood within the general sea-level community. In this paper, various geophysical factors affecting sea-level observations are discussed and the details and impacts of these processes on estimates of past ice volumes are introduced.

scholarly journals Refining Estimates of Polar Ice Volumes during the MIS11 Interglacial Using Sea Level Records from South Africa

2014 ◽  
Vol 27 (23) ◽  
pp. 8740-8746 ◽  
Author(s):  
Florence Chen ◽  
Sarah Friedman ◽  
Charles G. Gertler ◽  
James Looney ◽  
Nizhoni O’Connell ◽  
...  
Keyword(s):  
South Africa ◽  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheet ◽  
Sea Level Change ◽  
Polar Ice ◽  
Level Change ◽  
Isostatic Adjustment ◽  
West Antarctic ◽  
Numerical Predictions

Abstract Peak eustatic sea level (ESL), or minimum ice volume, during the protracted marine isotope stage 11 (MIS11) interglacial at ~420 ka remains a matter of contention. A recent study of high-stand markers of MIS11 age from the tectonically stable southern coast of South Africa estimated a peak ESL of 13 m. The present study refines this estimate by taking into account both the uncertainty in the correction for glacial isostatic adjustment (GIA) and the geographic variability of sea level change following polar ice sheet collapse. In regard to the latter, the authors demonstrate, using gravitationally self-consistent numerical predictions of postglacial sea level change, that rapid melting from any of the three major polar ice sheets (West Antarctic, Greenland, or East Antarctic) will lead to a local sea level rise in southern South Africa that is 15%–20% higher than the eustatic sea level rise associated with the ice sheet collapse. Taking this amplification and a range of possible GIA corrections into account and assuming that the tectonic correction applied in the earlier study is correct, the authors revise downward the estimate of peak ESL during MIS11 to 8–11.5 m.

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