A Boulder Beach Formed by Waves From a Calving Glacier Revisited: Multidecadal Tsunami–Controlled Coastal Changes in Front of Eqip Sermia, West Greenland

ABSTRACT The calving of glaciers regularly produces tsunami‐like waves that pose a serious threat to coastal environments. Those strong waves are not only able to move ice mélange and redistribute icebergs, growlers, or sea ice across a fjord but also flood and remodel neighbouring cliffs and beache...

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Bibliographic Details
Published in:Permafrost and Periglacial Processes
Main Authors: Kostrzewa, Oskar, Szczypińska, Małgorzata, Kavan, Jan, Senderak, Krzysztof, Novák, Milan, Strzelecki, Mateusz C.
Other Authors: Narodowe Centrum Nauki
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2024
Subjects:
Online Access:http://dx.doi.org/10.1002/ppp.2235
https://onlinelibrary.wiley.com/doi/pdf/10.1002/ppp.2235
Description
Summary:ABSTRACT The calving of glaciers regularly produces tsunami‐like waves that pose a serious threat to coastal environments. Those strong waves are not only able to move ice mélange and redistribute icebergs, growlers, or sea ice across a fjord but also flood and remodel neighbouring cliffs and beaches. Here, we analyze over 90 years (1929–2023) of coastal zone changes that occurred in front of Eqip Sermia. We show that calving waves play a dominant role in transforming the lateral moraine and forming a beach and spit system south of the glacier front. Part of the former moraine has transformed into a boulder‐dominated spit, which closed the lagoon over the years. By multidecadal analysis, we also detected a significant erosion of unconsolidated cliffs located on the opposite side of the bay (~0.53 m per year between 1985 and 2023). In addition, we demonstrate that even a single event (one calving wave) can remodel a beach surface by entrainment of up to 1.8‐m‐diameter boulders and the erosion of the beach surface by washing away sand and gravel from rocky outcrops. Our study constitutes important progress toward modes of paraglacial coastal evolution in regions characterized by rapidly retreating calving glaciers.