Coastal Geomorphology and Erosion at Iceland’s Reynisfjara Beach

April 6, 2020

Iceland as a site to study coastal geomorphology

Coastal geomorphology as a discipline of study is broad, ranging from studies such as the geomorphology of estuaries and deltas, to aeolian studies of coastal sediment transportation on beaches and dunes. It is for this reason that studies related to the overarching field of coastal geomorphology require narrowing their topic by geographic region, or specific location. Studies in cliff geomorphology, and the oceanic forces acting against them, is an example of a study that has been conducted in a variety of geographic regions.

However, there have been minimal studies of these processes in a specific location where the effects can be analyzed to provide estimates of future geomorphology in that area. Iceland, specifically its oceanic coasts, are of great geomorphological interest in these types of studies.

Iceland is home to a vast array of geological processes and unique environments (Gudmundsson, 2017), mostly from having gone through over 20 glaciations over the past 4–5 million years and being a volcanic hotspot (Geirsdóttir, Miller & Andrews, 2006). Wave-cut platforms, for example, are geological landforms found on cliff sides and edges that are formed by wave action and other environmental factors, ultimately causing cliff material to be eroded away over time. Thus, Iceland provides a plethora of possibilities for scientific study, making it equally a prime location for geomorphological study.

This brings us to the question this study will approach: what is the rate of coastal erosion, and how does the height, shape, and prevalence of wave-cut platforms vary along the cliffs found at Reynisfjara beach in southern Iceland?

Natural Tourism in Iceland

Iceland, known for its geological wonders and natural phenomena, is home to a very large tourism industry. This industry has seen a massive increase in the past decade, in large part from the use of social media to document and share travel photos and stories. Photos using the hashtag #Iceland on Instagram have been posted over 11.2 million times as of October 2019. This is extremely significant for Iceland because it has boosted travel industry statistics as well.

According to tourism statistics for Iceland in 2018, the country received 2,224,600 foreign visitors in 2017, resulting in an average growth rate of 24.3% since 2010 (Óladóttir, 2018). This large increase in popularity was also found to almost always be related to the natural features of the country. In fact, a whopping 92.4% of tourists responding to a survey explained that Iceland’s natural wonders were influential factors in deciding to visit (Óladóttir, 2018).

It is clear from these statistics that Iceland is unique in this way, which leads me to conclude that there is a wealth of physical geography to study in this country using field work.

Reynisfjara beach and coastline as a study subject

Iceland’s southern coastline and unique cliffs and beaches are of particular interest. Although these locales have been visited by international and local tourists for years, there has not been much interest or study on how these landscapes will change over time from erosion, climate change and other climatological forces (Stone & Orford, 2004)

The Reynisfjara (“black sand”) beach and surrounding cliffs are the specific topics of research here. It is unknown what the future looks like for this area, as climate change and its subsequent weather extremes affect the landscape through a variety of geomorphological processes. Coastal erosion, for example, is a process caused by aeolian and oceanic forces, which the beach is strongly affected by due to its geographic position.

Current geomorphological research on erosion and deposition from the ocean’s waves on coasts is detailed as well (Gardner, 2019), allowing for in-depth research technique development for the purpose of this study. Additionally, wave-cut platforms – where areas of the cliff are eroded away over time by outside factors – and their prevalence along a cliff length increase the risk of crumbling and falling cliff material, gradually altering the landscape over time. As climate change becomes more visible in the Northern Hemisphere, the amount of extreme, sporadic weather will be a directly linked effect.

Furthermore, climate fluctuations in the North Atlantic have been linked to chronologies of coastal erosion (Stone & Orford, 2004), proving that there is a relationship worth studying in this field. Dawson et al. (2004) identified a series of historical “climate see-saws” (significant fluctuations in climate) from Great Britain to Greenland and stretching across the entire North Atlantic Ocean. This also explained erosional patterns observed in Great Britain, Greenland and Iceland. The study concluded that, historically, tropospheric circulations (causing climate see-saws) have been directly linked to an increase in the severity and frequency of winter storms in the North Atlantic and consequently an increase in coastal erosion (Dawson et al., 2004).

Finally, there are various recorded instances of rockfalls and landslides at Reynisfjara beach itself. For example, the beach was deemed dangerous for tourists in the summer of 2019 from a huge rockslide, totalling an estimated 25,000 cubic metres in volume, from a section of cliff 50 metres long and 100 metres wide (Kyzer, 2019). Some boulders in the rockslide were as large as 3 metres in diameter, and it was reported that the material from this significant event ran all the way into the sea from the base of the Reynisfjall Mountain (Kyzer, 2019).

These findings bring forth the fact that coastal erosion in Iceland can be caused by natural fluxes in the severity of winter storms, and from extreme morphological changes and events, further proving that there are definite physical erosion processes at work at the Reynisfjara beach.

Rogue waves as a source of coastal erosion at Reynisfjara

Rogue waves are another aspect of interest at the Reynisfjara beach. A 2017 study found that since 2007 there have been three deaths and numerous accidents involving rogue waves at Reynisfjara (Truter, 2017). Although rogue waves seem unlikely to be common due to the nature of their name, this is not the case. Additional records have shown that South Iceland is prone to these rogue waves. A 2012 study of human-wave incidents around the world listed one event in which waves were large enough to hit a car on a pier, quickly sweeping a local resident into the ocean (Nikolkina & Didenkulova, 2012).

 From articles like these, it is made clear that extreme wave activity is clearly dangerous, that these waves are present in Southern Iceland, and that Reynisfjara is no different. Historical extreme (including rogue) waves have the possibility to leave a permanent mark on coastal sediments (Gardner, 2019). Waves with this much power ought to have obvious effects on the greater physical environment and the landscape as well, however these effects have yet to be determined for Reynisfjara’s beach and coast specifically.

When soil and rock surfaces are over-saturated from waves and other various types of weathering (mostly wind and precipitation), the process of erosion and breakdown occurs. This can be caused by throughflow of groundwater, open aquifers, or simply the force of gravity. Saturated soils are more susceptible to movement, and porous soils can take in more water than other soil types. Depending on the soil type along the cliffs at Reynisfjara, some erosional processes will occur faster than others. Other factors must be considered as well, like the climate, topography, aspect, vegetation, and animal activity (Dvořák & Novák, 1994).

From the climate fluctuations (see-saws) mentioned previously, we know that the annual climate at Reynisfjara is never predictably consistent. However, we can deduct the possibility that changes will be more extreme when the winter storm season is stronger, as this was mentioned in multiple studies (Dawson et al., 2004, Stone & Orford, 2004). Measuring the moisture content along several sections of the cliff face at Reynisfjara over time will allow for a better understanding of soil type, soil saturation levels and the contribution to coastal erosion on this coastline.

Sediment and grain size at Reynisfjara beach

As waves leave marks on coastal sediment, it is important to address what coastal sediment in Southern Iceland looks like. Many studies document the presence of boulders on Icelandic beaches from sedimentary rock and metamorphic (volcanic) material deposits (Etienne & Paris, 2010).

These boulders are either from a) the landscape and cliff edges in the beach area; b) aged volcanic flow; or c) a different morphotype/collection of boulders in a specific formation (Etienne & Paris, 2010). The first is the most common in the Reynisfjara area. These boulder features are important to note when it comes to coastal geomorphology because they can interfere with or contribute to the acceleration of physical and chemical processes occurring at the site, like erosion. Boulders on wave-cut platforms increase weight and the amount of pressure for collapse on these structures. This is the case at Reynisfjara, where boulders are present on top of the main cliffs, and these boulders have not been studied in depth. This is another aspect of study to be addressed at Reynisfjara.

Grain size on beaches is another aspect to possibly study. Little is known about how grain size and geomorphology connect (Bujan, Cox & Masselink, 2019), but there is some research revolving around how geomorphological processes can be altered due to grain size. One of these factors, for example, is how grain size controls physical factors (like tide range) on the beach (Bujan, Cox & Masselink, 2019); a beach full of boulders or other large grained materials (like cobblestones) near the waters edge will act as a wall or barrier to the range of tide movement. A tide with more boulders will be more broken up than on a smooth, sandy beach. According to photographs of the beach, Reynisfjara is an interesting combination of multiple grain sizes. Smaller portions of the beach are classified as a cobblestone pattern with smooth, rounded stones, while the majority consists of the infamous black, coarse sand, much like sand one would find in a stereotypical beach. This contrast in texture allows us to assume that there are several materials present in the sand portion of the beach, which could affect the speed of geomorphological processes once studied further.

Concluding findings and a call to action

Reynisfjara is home to a unique physical environment that is constantly changing. There are many reasons for this, including erosion, but climate change creates an even deeper-rooted issue that will inevitably impact Reynisfjara, and Iceland’s tourism industry altogether, in the next decade. As we work towards understanding the geomorphology of coastal environments in greater depth through scientific research, it is even more important that we consider ways to prevent further harm to these unique places. Reynisfjara’s natural beauty makes it famous for a reason, and I urge you to consider ways you can raise awareness, promote environmental security and reduce your personal impact on the planet so we can preserve naturally significant areas like Reynisfjara for decades to come.

Reviewed and edited by Meg Schmidt, Masters of Science student, Geography and Environmental Management

References

  • Bujan, N., Cox, R., & Masselink, G. (2019). From fine sand to boulders: Examining the relationship between beach-face slope and sediment size. Marine Geology, 417, 106012.
  • Dawson, A., Elliott, L., Noone, S., Hickey, K., Holt, T., Wadhams, P., & Foster, I. (2004). Historical storminess and climate ‘see-saws’ in the North Atlantic region. Marine Geology, 210(1-4), 247–259.
  • Dvořák, J., & Novák, L. (n.d.). Soil Conservation and Silviculture, Chapter 3. Developments in Soil Science, 23, 39–80.
  • Etienne, S., & Paris, R. (2010). Boulder accumulations related to storms on the south coast of the Reykjanes Peninsula (Iceland). Geomorphology, 114(1-2), 55–70. 
  • Gardner, J. (2019). How water, wind, waves and ice shape landscapes and landforms: Historical contributions to geomorphic science. Geomorphology. 
  • Geirsdóttir, Á., Miller, G. H., & Andrews, J. T. (2007). Glaciation, erosion, and landscape evolution of Iceland. Journal of Geodynamics, 43(1), 170–186. 
  • Gudmundsson, A. (2017). The Glorious Geology of Icelands Golden Circle. GeoGuide.
  • Nikolkina, I., & Didenkulova, I. (2011). Catalogue of rogue waves reported in media in 2006–2010. Natural Hazards, 61(3), 989–1006.
  • Stone, G. W., & Orford, J. D. (2004). Storms and their significance in coastal morpho-sedimentary dynamics. Marine Geology, 210(1-4), 1–5.
  • Truter, A. (2017). Management of Coastal Hazardous Sites: A case study of Reynisfjara Beach, Iceland. University of Akureyri, Faculty of Business and Science.