Hydrographic surveys as an art of delineating the impact of climate change on the coastal environment
Abstract
Marine acoustic techniques are quite efficient in remote seabed classifications and hydrographic investigations by providing highly detailed information about broad areas of the seafloor and the subsurface layers in a short period of time. Climatic change is considered as the forcing factor for the eustatic sea-level-rise along the Mediterranean coast, leading to the large coastal inundation and the subsidence of the ancient maritime installations, these ancient sites can be used as indicators for the relative changes in sea-level through later times.
Marine surveys were carried out to delineate the coastal geomorphological changes associated with sea level rises and natural hazards along some areas on the coast of Alexandria during the last two millennia. Hydrographic and seismic surveys were implemented in the study area by using a multi-beam echo-sounder, side scan sonar, and sub-bottom profiler, then the acoustic data were calibrated with dated core samples
and ROV camera images. Multi-beam is considered the most commonly used tool in harbor surveys utilizing the returned acoustic signals to measure the depth of the seafloor, while the side scan sonar instrument provides high-resolution images for the elevated structures from the seafloor depending on the backscatter strength of the signal, and the sub-bottom profiler uses chirp waves that deliver high resolution vertical images for the subsurface sediment situation. Results of sonar imaging and bathymetric mapping outlined submerged margins of archaeological remains related to ancient Ptolemaic and Greek ports.
Seismic interpretations revealed significant changes in the coastal geomorphology, where the massive burial of the port structure indicated the occurrence of sudden natural hazards originated from seismic waves; therefore, a destructive tsunami wave accompanied by sediment slumping that followed by eustatic sea-level-rise seems to be the dominant factors for this dramatic burial. The research results showed the potentiality of hydrographic surveys in detecting climate change indicators.
Keywords
Full Text:
PDFReferences
Becker, M., Meyssignac, B., Letetrel, C., Llovel, W., Cazenave, A., Delcroix, T., “Sea level variations at tropical Pacific islands since 1950” Global Planet Change, 94(33), 2012, pp. 85–98.
Bird, E. C., “Coastal erosion and rising sea level, in Sea Level Rise and Coastal Subsidence”. edited by Millimann, J. D. and Haq, B. U., 1996, pp. 87–103. Kluwer Acad., Dordrecht, the Netherlands.
Chalari, A., Papatheodorou, G., Geraga, M., Christodoulou D. and Ferentinos, G., “A marine geophysical survey illustrates Alexandria’s Hellenistic past”. Zeitschrift fur Geomorphologie, 53(1), 2009, pp. 191-212.
Fekry, A., “Impact of Sea level Changes on the Geomorphological Features along some Areas of Alexandria Coast, Egypt”. Ph.D. Thesis, Tanta University, 2021.
Folk, R.L. “Petrology of Sedimentary Rocks”. Hemphill Publishing Company: Austin, TX, USA, 1974.
Goddio, F., Bernand, A., Bernand, E., Darwish, I., Kiss, Z., Yoyotte, J., “Alexandria: The Submerged Royal Quarters.” Periplus, London, 1998, P. 274.
Guidoboni, E., Comastri, A., Traina, G., “Catalogue of Ancient Earthquakes in the Mediterranean Area up to the 10th Century.” Bologna: Istituto Nazionale di Geofisica, 1994, 504. p.
Hamouda, A., “A reanalysis of the AD 365 tsunami impact along the Egyptian Mediterranean coast.” Acta Geophys., 2010, 58, 687–704.
Hamouda, A., El-Gendy, N., El-Shishtawy, A., El-Gharabawy, S., Fekry, A., “Submergence of the Western Greco-Roman Archaeological Site at the Eastern Harbor of Alexandria: Emerged from High Resolution Geophysical Mapping.” Quaternary, 2021, 4, 22.
Jondet, M. G., “Les Ports Submergés de l’Ancienne île de Pharos”, Cairo, L’Institut Egyptien, 1916, 101 p.
Kemp, A., Horton, B., Donnelly, J., Mann, M., Vermeer, M., Rahmstorf, S., “Climate related sea level variations over the past two millennia.” Proc. Natl. Acad. Sci. U. S. A., 2011, 108(27), 11017–11022.
Lambeck, K., Yokoyama, Y., Purcell, A., “Into and out of the Last Glacial Maximum: sea-level change during oxygen isotope stages 3 and 2.” Quat. Sci. Rev., 2002, 21,343–360.
Mastronuzzi, G., Aringoli, D., Aucelli, P., Baldassarre, A., Bellotti, P., Bini, M., Biolchi, S., Bontempi, S., Brandolini, P., Chelli, A., Davoli, L., Deiana, G., Muro, S., Devoto, S., Di Paola, G., Donadio, C., Fago, P., Ferrari, M., Furlani, S., Valente, A., “Geomorphological map of the Italian coast: From a descriptive to a morphodynamic approach.” Geografia Fisica e Dinamica Quaternaria., 2017, 40. 161-195. 10.4461/GFDQ.2017.40.11.
Mourtzas, N.D., “A palaeogeographic reconstruction of the seafront of the ancient city of Delos in relation to Upper Holocene sea level changes in the central Cyclades.” Quat. Int., 2012, 250, 3–18.
Stanley, J. D., Carlson, R., Beek, G., Jorstad, T., Landau, E., “Alexandria, Egypt, before Alexander the Great: A multidisciplinary approach yields rich discoveries.” GSA Today, 2007, 17, 4–10.
Stiros, S., “The AD 365 Crete earthquake and possible seismic clustering during the fourth to sixth centuries AD in the Eastern Mediterranean: a review of historical and archaeological data”, Journal of Structural Geology, 2001, 23(2–3), P. 545-562.
Stiros, S., “The AD 365 Ammianus tsunami in Alexandria, Egypt, and the Crete ca. 365 fault and tsunami.” Arab J Geosci, 2020, 13, 716.
Strabo, “The Geography”, Translated by H.L. Jones, Cambridge, Harvard University Press, 1917-1932 (8).
Wilken, D., Wunderlich, T., Feldens, P., Coolen, J., Preston, J., Mehler, N., “Investigating the Norse Harbour of Igaliku (Southern Greenland) Using an Integrated System of Side-Scan Sonar and High-Resolution Reflection Seismics.” Remote Sens., 2019, 11, 1889.
DOI: http://dx.doi.org/10.21622/MARLOG.2022.11.226
Refbacks
- There are currently no refbacks.
Copyright (c) 2023 Ahmed M. Fekry, Amr Z. Hamouda
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
The International Maritime Transport and Logistics Journal (MARLOG)
E-ISSN: 2974-3141
P-ISSN: 2974-3133
Published by:
Academy Publishing Center (APC)
Arab Academy for Science, Technology and Maritime Transport (AASTMT)
Alexandria, Egypt