Geohazard assessment of the coastal zone – the case of the southern Baltic Sea

Abstract

As so ci ate Ed i tor: Tomis³aw Go³êbiowski Re search by the Pol ish Geo log i cal Sur vey has been car ried out along the south ern Bal tic coastal zone over a dis tance of 38 km. The Bal tic Sea is clas si fied as non-tidal, and its south ern coasts are built en tirely of weakly lithified sed i men tary rocks. These de pos its form three main types of coast, namely cliffs, bar ri ers and al lu vial coasts (wetlands), with the re search fo cusing on the first two. Meth ods in clud ing re mote sens ing, map ping (geo log i cal, hydrogeological), off shore sur vey (bathymetric and geo phys i cal mea sure ments), lab o ra tory anal y ses and mod el ling re vealed a num ber of nat u ral haz ards. These are, respec tively: (1) per ma nently oc cur ring haz ards, caus ing ma te rial dam age such as: land slides, coastal ero sion and sea bed ero sion; (2) in ci den tal haz ards such as dune break age and storm surge over flow and (3) hy po thet i cal threats that may oc cur in the fu ture, such as hydrogeohazards de fined here as flood ing re sult ing from ground wa ter level rise or more rarely, earthquake threats.

Numerical model of late Pleistocene and Holocene ice-sheet and shoreline dynamics in the southern Baltic Sea, Poland

“…Glacial phases: L, Leszno; Poz, Poznań; Pom, Pomeranian; G, Gardno; SB, southern Baltic; SMB, Southern Middle Bank. SBS development phases (Uścinowicz, 1995, 1999): BIL, Baltic Ice Lake; YS, Yoldia Sea; LGM, last glacial maximum; LG1–3, late-glacial stadials 1–3; LI1–2, late-glacial interstadials 1 and 2; B/A, Bolling/Allerod interstadial; YD, Younger Dryas; H1, Heinrich event 1; ELA, equilibrium line altitude of glacier (modified from Marks et al, 2016), coordinate system ETRS 1989 PL-1992 (EPSG 2180).…”

“…6).

Figure 6.Palaeogeography (A) and palaeodynamics of the Southern Baltic Sea (SBS) development in the Holocene in the light of the relative sea-level rise (SLR) curve (Uścinowicz, 1995, 1999, 2004, 2014), modified from the 4F model, the icon contains a hyperlink to the 4F model, last accessed on February 4, 2021. (B) Relative SLR curve for the SBS (modified from Uścinowicz, 2004, 2014; and supplemented with the Baltic developmental dynamics from the current study.

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“…A primary, fully operational model that is adaptable and expandable was constructed in the Desmos environment. Because development of the Baltic coastline in the past was related to the retreat of the Scandinavian ice sheet (Uścinowicz, 1995, 1999, 2004, 2006, 2014; Marks, 2002; Marks et al, 2016; Harff et al, 2017; Rosentau et al, 2017; Hall and van Boeckel, 2020), it is justified to use markers such as a range of individual phases of glaciation and consecutive shoreline frontiers for the purpose of modelling. Owing to the development of the methodology presented in the preceding sections, the 4F model was applied to determine the deglaciation palaeodynamics during the late Vistulian period (Weichselian/Würm glaciation), which included the limits of glacial phases during MIS 2, from the Leszno Phase (L, 24 ka BP) (Marks et al, 2016), through the Poznań Phase (Poz, 20–19 ka BP), the Pomeranian Phase (Pom, 17–16 ka BP) (Marks et al, 2016), the Gardno Phase (G, 16.8–16.6 ka BP), the Słupsk Bank Phase (SB, 16.2–15.8 ka BP) up to Southern Middle Bank Phase (SMB, 15.4–15.0 ka BP) (Uścinowicz, 1995, 1999), followed by the Baltic basin development in the Holocene (Uścinowicz, 1995, 1999, 2006).…”

“…The input data for the 4F model comprised maps that represent the results of analyses performed with the use of geologic, geomorphological, and oceanographic research (coupled with radiocarbon dating). Specifically, the 4F model inputs such as time ( t 1 to t 16 ) and baseline geospatial locations were derived from Marks et al (2016) and Uścinowicz (1995, 1999). They were geocoded using the GIS ArcMap suite in accordance with standard procedures, which were applied in order to view, edit, register, and analyse geospatial data.…”

“…As the degree of the polynomial increases, the quality of the representation decreases. This is reflected in the value of the correlation coefficient.

Figure 4.Nested model of shift dynamics in the time function (dashed line) of the Scandinavian ice-sheet recession in the late Pleistocene (Marine Oxygen Isotope Stage 2 [MIS 2]) based on Marks (2002) and Marks et al (2016) (black); the development of the SBS in the Holocene (MIS 1) (blue) (Uścinowicz, 1995, 1999); and forecasts of the pace and extent of erosion in the Anthropocene, in the light of projected gmsl-rise RCP8.5 and RCP2.6 scenarios: red, Oppenheimer et al (2019), and green, Golledge (2020), modified from the 4F model nested matrix. The icon contains a hyperlink to the 4F model, last accessed on February 4, 2021.

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