scholarly journals Finding of a Holocene marine layer in Algarrobo (33°22'S), central Chile. Implications for coastal uplift

2010 ◽  
Vol 33 (2) ◽  
pp. 339 ◽  
Author(s):  
Alfonso Encinas ◽  
Francisco Herve ◽  
Rodrigo Villa-Martinez ◽  
Sven N. Nielsen ◽  
Kenneth L. Finger ◽  
...  

A buried Holocene marine bed was discovered upon drilling a water well in Algarrobo (33°22'S), located on the coast of central Chile. Radiocarbon dating of a wood fragment found within the deposit indicates an age of 6450 cal yr BP. The top of this bed, 0.25 m-thick, was reached at an elevation of 3.8 m above mean sea level. This bed contains abundant monospecific faunas of foraminifers (Ammonia tepida) and ostracodes (Cyprideis beaconensis), indicative of deposition in a very shallow, transitional marine environment. Palynologic analysis reveals a Chenopodiaceae-dominated (~70%) assemblage, indicating a relatively arid and warm climate.

2016 ◽  
Vol 6 (2) ◽  
Author(s):  
Prijantono Astjario ◽  
D.A. Siregar

Wilayah pantai Ngungap, kawasan pesisir selatan Wonogiri, Jawa Tengah merupakan daerah jalur anjak dimana terumbu karang Kuarter tersingkap dari garis pantai hingga pebukitan tinggi. Enam undak laut terbentuk sejajar dengan garis pantai hingga mencapai ketinggian lebih dari 300 meter di atas muka laut. Hasil pentarikhan Radiokarbon tiga fosil terumbu karang dari undak laut termuda yang dapat berkontribusi terhadap perhitungan proses pengangkatan kawasan pantai Ngungap. Undak laut termuda menunjukan bahwa rata-rata aktivitas tektonik pengangkatan diwilayah pantai Ngungap, kawasan pesisir selatan Wonogiri adalah 5 mm/tahun. Pengangkatan rata-rata pesisir selatan Wonogiri jauh berbeda dengan kecepatan kawasan pantai-pantai tektonik aktif lainnya di Indonesia. Kata kunci : anjak, terumbu karang, undak laut, pentarikhan, pantai Ngungap Jawa Tengah The Ngungap coast of the southern coastal zone of Wonogiri, Central Jawa, situated in the central portion of the arcuate thrustbelt where Quaternary reefs show maximal elevation from coastline up to high hinterland. Six terraces have been formed parallel to the coast line and extensively exposed up to more than 300 meters above mean sea level. Three Radiocarbon dating of coral reef derived from the lowest terraces can be contributed to the uplift calculation in the Ngungap area. The lowest terrace alows uplifting tectonic activity in the coast of Ngungap in the order of 5 mm/years. The uplift rate of southern coast of Wonogiri is different to the rate of active tectonic coastal areas in the eastern Indonesian region. Keywords: thrustbelt, reef, terrace, dating, Ngungap coast of Central Java


2006 ◽  
Vol 33 (2) ◽  
Author(s):  
Alfonso Encinas ◽  
Francisco Hervé ◽  
Rodrigo Villa-Martínez ◽  
Sven N Nielsen ◽  
Kenneth L Finger ◽  
...  

2007 ◽  
Vol 86 (4) ◽  
pp. 333-354 ◽  
Author(s):  
H.J.A. Berendsen ◽  
B Makaske ◽  
O. van de Plassche ◽  
M.H.M van Ree ◽  
S. Das ◽  
...  

AbstractWe present new local groundwater-level rise data from two Late Glacial aeolian dunes, located near Barendrecht and Oud-Alblas in the western Rhine-Meuse delta. These data are based on AMS radiocarbon dating of terrestrial macrofossils, collected from the base of peat formed on the slopes of these dunes. This method avoids contamination of bulk peat samples by old soil carbon or younger rootlets and rhizomes, as well as the hardwater effect. The new data are used to assess the reliability of previously published groundwater-level index data based on conventional radiocarbon dating of bulk basal peat samples from the slopes of the Late Glacial aeolian dunes at Barendrecht, Hillegersberg, Bolnes and Wijngaarden, all located in the western Rhine-Meuse delta.Comparison of the new and published groundwater-level data shows no significant systematic difference between conventionally dated bulk peat samples and AMS-dated samples of terrestrial macrofossils. The new data from the dune at Barendrecht confirm the reliability of the younger than 6600 cal yr BP age-depth data from the dunes at Hillegersberg and near Bolnes. This result supports the validity of this part of the mean sea-level (MSL) curve for the western Netherlands. Consequently, the position of the groundwater-level curve for Flevoland (central Netherlands) below this MSL curve can most likely be attributed to differential land-level movement.The available data show that the groundwater-gradient effect in the western Rhine-Meuse delta became less than 5 cm/km after 6600 cal yr BP. Finally, temporal correlation between temporary increases in local groundwater-level rise with known shifts of river courses in the delta plain suggests, that avulsions can explain sudden local deviations from the trend in groundwater-level rise. A general conclusion of this study is that a complex relationship exists between sea level and local delta-plain water levels.


1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.


2015 ◽  
Vol 15 (11) ◽  
pp. 2557-2568 ◽  
Author(s):  
M. Wronna ◽  
R. Omira ◽  
M. A. Baptista

Abstract. In this paper, we present a deterministic approach to tsunami hazard assessment for the city and harbour of Sines, Portugal, one of the test sites of project ASTARTE (Assessment, STrategy And Risk Reduction for Tsunamis in Europe). Sines has one of the most important deep-water ports, which has oil-bearing, petrochemical, liquid-bulk, coal, and container terminals. The port and its industrial infrastructures face the ocean southwest towards the main seismogenic sources. This work considers two different seismic zones: the Southwest Iberian Margin and the Gloria Fault. Within these two regions, we selected a total of six scenarios to assess the tsunami impact at the test site. The tsunami simulations are computed using NSWING, a Non-linear Shallow Water model wIth Nested Grids. In this study, the static effect of tides is analysed for three different tidal stages: MLLW (mean lower low water), MSL (mean sea level), and MHHW (mean higher high water). For each scenario, the tsunami hazard is described by maximum values of wave height, flow depth, drawback, maximum inundation area and run-up. Synthetic waveforms are computed at virtual tide gauges at specific locations outside and inside the harbour. The final results describe the impact at the Sines test site considering the single scenarios at mean sea level, the aggregate scenario, and the influence of the tide on the aggregate scenario. The results confirm the composite source of Horseshoe and Marques de Pombal faults as the worst-case scenario, with wave heights of over 10 m, which reach the coast approximately 22 min after the rupture. It dominates the aggregate scenario by about 60 % of the impact area at the test site, considering maximum wave height and maximum flow depth. The HSMPF scenario inundates a total area of 3.5 km2.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hamish Steptoe ◽  
Nicholas Henry Savage ◽  
Saeed Sadri ◽  
Kate Salmon ◽  
Zubair Maalick ◽  
...  

AbstractHigh resolution simulations at 4.4 km and 1.5 km resolution have been performed for 12 historical tropical cyclones impacting Bangladesh. We use the European Centre for Medium-Range Weather Forecasting 5th generation Re-Analysis (ERA5) to provide a 9-member ensemble of initial and boundary conditions for the regional configuration of the Met Office Unified Model. The simulations are compared to the original ERA5 data and the International Best Track Archive for Climate Stewardship (IBTrACS) tropical cyclone database for wind speed, gust speed and mean sea-level pressure. The 4.4 km simulations show a typical increase in peak gust speed of 41 to 118 knots relative to ERA5, and a deepening of minimum mean sea-level pressure of up to −27 hPa, relative to ERA5 and IBTrACS data. The downscaled simulations compare more favourably with IBTrACS data than the ERA5 data suggesting tropical cyclone hazards in the ERA5 deterministic output may be underestimated. The dataset is freely available from 10.5281/zenodo.3600201.


2021 ◽  
Vol 9 (6) ◽  
pp. 595
Author(s):  
Américo Soares Ribeiro ◽  
Carina Lurdes Lopes ◽  
Magda Catarina Sousa ◽  
Moncho Gomez-Gesteira ◽  
João Miguel Dias

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.


2021 ◽  
Vol 9 (2) ◽  
pp. 205
Author(s):  
Serafino Afonso Rui Mucova ◽  
Ulisses Miranda Azeiteiro ◽  
Walter Leal Filho ◽  
Carina Lurdes Lopes ◽  
João Miguel Dias ◽  
...  

Mean sea-level is expected to rise significantly by 2100 in all scenarios, including those compatible with the objectives of the Paris Climate Agreement. Global sea level rise projections indicate devastating implications for populations, ecosystem services and biodiversity. The implications of the sea-level rise (SLR) on low-lying islands and coastal regions and communities are substantial and require deep-rooted coping measures. In the absence of adequate responses for coping, Mozambique is expected to record huge losses, with an impact on the economy and development in many sectors of its coastal regions mainly in northern Mozambique. This research aimed to perform projections on SLR in Mozambique, and to understand its role and implications on the north coast of the country. SLR was estimated through the analysis of model outputs that support the global estimates of the fifth IPCC report near the Mozambican coast, for each of the four representative concentration pathways (RCPs) scenarios. Regional coastline retreat and coastal erosion were estimated through the results of global sandy coastlines projections developed by Vousdoukas. Mean sea-level rise projections indicate that regional estimates for the Mozambican coast are relative higher than global estimates (~0.05 m) for all representative concentration pathways (RCPs). Yet, we highlight significant differences in sea-level rises of 0.5 m, 0.7 m or 1.0 m by 2100 compared to the global mean. It is expected that with the increase in the mean sea level in the northern part of the Mozambican coast, erosive effects will increase, as well as the retreat of the coastline until 2100. With this, the tourism sector, settlements, ecosystem services and local populations are expected to be significantly affected by 2050, with increased threats in 2100 (RCP4.5, RCP8.5). Local responses for coping are proposed and properly discussed for the RCP4.5 and RCP8.5 scenarios through 2100.


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