European Geologist Journal 58

Invisible landscapes revealed: geophysical insights into the underwater extensions of terrestrial landforms

 

by Michael Strupler 1*

1 Institute of Geological Sciences, University of Bern, Switzerland

Contact: michael.strupler@unibe.ch

Abstract

The morphology of many lakes in mountainous regions is attributed to their deglaciation history and associated processes. However, the visibility within these lakes is often limited due to suspended sediment and organic particles, making it challenging to discern landforms below the water’s surface. As a result, lakes are regarded by many as unknown water bodies, with limited understanding of their submerged features. Recent advancements in high-resolution geophysical data have made it possible to unveil underwater morphologies to a wider audience. This article presents three pristine examples from perialpine Swiss lakes, illustrating the seamless transition of subaerial landforms into the nearshore zone. Understanding these geomorphic expressions enhances our knowledge of landscape formation and supports better land use and hazard management decision-making.

Cite as: Strupler, M. (2024). Invisible landscapes revealed: geophysical insights into the underwater extensions of terrestrial landforms. European Geologist, 58. https://doi.org/10.5281/zenodo.14840703

Creative Commons License This work is licensed under a Creative Commons Attribution 4.0 International License.

1. Introduction

Landscapes and landforms are shaped by various processes that operate over different scales regarding space and time. Hence, geomorphic investigations are important to understand these processes and the evolution of landforms. Moreover, understanding geomorphodynamic processes is crucial for hazard assessment and mitigation.

The Swiss Alpine landscape was formed by a combination of tectonic, glacial, and fluvial processes that led to the formation of deep fjord-type Alpine and perialpine lakes (Figure 1). Such lakes are typically bordered by steep slopes, both above and below the water’s surface. The underwater slopes in these lakes typically exhibit inclinations ranging from 10° to 25°. Such slope gradients are particularly sensitive to subaqueous mass movements [1–4]. An overview of the characteristics of Swiss perialpine lakes, including their area, depth, sedimentology, and information on historical mass movements and their consequences, is available in [5–7].

Whereas the subaerial geomorphology is often identifiable by eye, landforms that are located below the water surface are often hidden due to limited visibility caused by suspended sediment, and organic particles. Many descriptions of landscapes and geomorphic interpretations are limited to the subaerial domain and do not include the subaqueous environment.

During the past two decades, an abundance of high-resolution geophysical data, including seismic reflection and multibeam echosounder data, has been acquired on Swiss perialpine lakes. These datasets reveal a great diversity of subaqueous landforms, including underwater moraines [8, 9], deltas [10–12], mass movement erosion and deposition zones [1, 3, 13–17], pockmarks [18, 19], canyons, gullies and terraces [15].

Interpreting these landforms allows us to estimate information about glacier extents and stillstands, sediment dynamic processes, currents, and fluid fluxes. Based on this information, the potential for future geological events, including cascading hazards, such as landslide-induced tsunamis, can be estimated and assessed [1, 6, 14, 20–25].

This article presents and analyses three pristine examples of landforms transitioning from the subaerial to the subaqueous domain. These landforms are identified and characterised using high-resolution geophysical datasets, including topographic, bathymetric, and seismic reflection data. Through these examples, this article aims to highlight the significance of an integrated investigation of landforms that transition between these domains to better understand the formation, evolution, and dynamics of these features. The main purpose of this article is to inspire and motivate the reader to visualise the primarily hidden subaqueous landforms. The findings demonstrate that the advanced quality of modern underwater geophysical data now enables the detailed visualisation of previously poorly understood subaqueous landscapes, unlocking new possibilities for various applications.

Figure 1: Shaded relief of Switzerland indicating the location of the 3 examples: (1) Molasse Terraces in Lake Geneva, (2) a rockslide, and (3) a subaqueous sill, both located in Lake Lucerne. Data: [26, 27]

2. Materials and Methods

Description and analysis of the landforms are mainly based on publicly available digital datasets: The freely available bathymetric models (termed “DBM” hereafter) of Switzerland, “SwissBATHY3D” [28] and existing Sparker seismic reflection data of the lake basins [8, 9] (data available upon request) are used to characterise the subaqueous geomorphology.

To characterise the terrestrial landforms bordering the lakes, data from the freely available digital elevation model “SwissALTI3D” [29] (termed “DEM” hereafter) are used. In addition, geological information is retrieved from the “GeoCover” vector data [30]. Information on tectonic units was retrieved from the “GeoMaps 500” vector dataset [31].

SwissAlti3D data is available for download at spatial resolutions of 0.5 m and 2 m, while SwissBathy3D offers resolutions of either 1 m or 2 m, depending on the specific lake. Hence, for homogenisation purposes, the DEM and DBMs were resampled to a raster resolution of 2 m and merged.

Basic operations on the raster data, such as merging individual raster mosaics, clipping, and resampling were conducted using GDAL [32] from the command line interface. The free software QGIS v. 3.34 [33] was used to visualise the topographic and bathymetric data and to analyse the landforms geomorphologically. Specifically, the expressions of selected landforms are described. These are related to various past and present glacial, fluvial, and anthropogenic processes responsible for their formation.

3D illustrations of the combined topography and bathymetry were created with the “Rayshader” package [34] for the free statistical software R [35].

Sparker seismic data was interpreted with “Kingdom” seismic and geological interpretation software [36].

3. Results

In this section, three examples of geophysical data are presented and analysed. The first example data is from Lake Geneva (Western Switzerland), and the second and third examples are from Lake Lucerne (Central Switzerland).

3.1. Molasse Terraces in Lake Geneva

Lake Geneva is situated in the southwestern region of Switzerland, where it shares its borders with France (Figure 1). Geologically, the lake is flanked by the Alps to the south and the Jura Mountains to the north. The lake level is located at 372 m a.s.l. [37]. The elongated lake basin itself was glacially excavated in the western Alpine foreland, which mainly consists of Tertiary Molasse deposits with alternating layers of sedimentary rocks [38]. A sequence of glacial and lacustrine deposits covers the substratum of the lake basin. On the northeastern shore of the lake, adjacent to the Lavaux Wine region, the high-resolution bathymetric dataset reveals underwater ridges oriented in a northwest-southeast direction (Figure 2).

Figure 2: (a) 3D visualisation of the Molasse Terraces in Chexbres. (b) Map view of the site. Terrestrial outcrops of the Subalpine Molasse Terraces are indicated in light yellow (data: SwissBATHY3D, SwissALTI3D, and GeoCover [28–30]). The sediment input from the river (dotted area) smooths the terrasse ridges locally.

The exposed structures in this area create terraces, with step widths ranging from approximately 130 m to 200 m and extending up to 2 km on land and about 1 km underwater. On the land-based terraces, smaller terraces can be observed (step widths of ca. 5-15 m), which have been constructed for winemaking purposes. These underwater terraces were already interpreted as subaquatic outcrops of conglomerate of the Subalpine Molasse by [39]. The lithology of the “Mont Pèlerin Conglomerate” consists of limestones, sandstones, marlstones, and conglomerates [30]. The terraces in the shown dataset extend from above lake level down to ca. 150 m below lake level. Near river mouths, terraces are smoothed out by fluvial sediment and traces of sediment mobilisation. The step structures, however, are mostly very crisp.

The existence of these terraces can be interpreted as a combination of lithological variability, tectonic activity, and glacial influence: The alternating sedimentary layers in the Subalpine Molasse show different properties, and therefore react differently to erosion. Relatively harder rocks like conglomerates and sandstones may resist erosion more than softer rocks like marls. The dip of the terraces is related to the thrusting and folding of the Molasse sediments during orogeny. Glacial erosion led to the formation of overdeepened troughs.

3.2. Rockfall at Lake Lucerne (Obermatt Quarry)

Lake Lucerne (434 m a.s.l. [37]) is a perialpine Lake located in central Switzerland (Figure 1). Due to its geologic-geomorphic predisposition, the area has experienced a plenitude of gravitational mass movements since deglaciation [40]. Both in the DEM and DBM, traces of the well-documented Obermatt rock-irregular slide that occurred at a shut down quarry in multiple phases (main events 1963,1964, and summer 2007) are identifiable. The events in 1963, 1964, and 2007 had limestone [30] rock volumes of ca. 20 × 103 m3, 70 × 103 m3 , and 35 × 103 m3 that were partially deposited on the base plateau and partially entered the water, where they caused local impulse waves with amplitudes of ca. 4, 15, and 5-6 m respectively [40–42].

Figure 3 shows the source area and Mass Transport Deposit (MTD) of these events. The study site is located at the border between the Helvetic Nappes and the Subalpine Molasse [43].

Figure 3: a) 3D visualisation of the Obermatt rockslide source area and MTD. b) Map view of the site with the rockslide scar (red dashed line), MTD extent (black dashed line), and blocky debris indicated. Data: SwissBATHY3D [28] and SwissALTI3D [29].

The source area of the rockslide is characterised by very steep (almost vertical, i.e. >70°) slopes. Due to the quarry activity, a ca. 50 m long (perpendicular to the shore) and ca. 120 m wide plateau is located at the base of the slope. At the shoreline, the slope continues to descend in a very steep manner with angles of 30-40° and transitions immediately into a flat basin at a water depth of ca. 140 m. At this depth, located ca. 200 m from the shoreline at the foot of the slope, the shore-proximal section of the MTD starts. The MTD identifiable in the DBM has a length of ca. 500 m and a width of ca. 300 m. The MTD has a rougher texture than its surroundings with some larger blocks (diameter: up to 50 m, height: ca. 1-3 m) visible. The MTD is a frontally emerging type [44]. According to [3], the MTD has a volume of ca. 0.4 x 109 m3. As the high-resolution DBM [3] was acquired after the three events (occurring temporally very close) at Obermatt, it is difficult to impossible to distinguish single phases from each other. It would only be possible to assign individual deposits to a respective event phase in such a case by conducting a bathymetric data acquisition immediately after each event and constructing differential DBMs.

3.3. Subaqueous Molasse Ridge in Lake Lucerne (“Kreuztrichter ridge”)

The substratum of Lake Lucerne’s northern basins is tectonically primarily located in the Subalpine Molasse, which generally dips southeastward towards the Alps [43]. In 2011, the subbottom of Lake Lucerne was surveyed with a Sparker (150-1500 Hz central frequency) seismic acquisition system [8, 9]. Here, bathymetric data (Figure 4a) is presented alongside an extract of these seismic reflection data (Figures 4b and 4c) within the context of the article’s objective: making invisible landforms visible. To keep as much information as possible about the structure of the subsurface, seismic data is not filtered with a band-pass filter.

Figure 4: (a) Bathymetric data of the “Kreuztrichter ridge”. (b) Sparker seismic reflection data of Profile AB. Vertical exaggeration: 5.4 x. (c) Interpreted data showing the three seismic facies (I – III). On the eastern flank of the ridge, layered eastward-dipping reflections can be identified. TWT = Two-way traveltime. Data: SwissBATHY3D [28], SwissALTI3D [29], and [8, 9].

Due to its low central frequency and the related long wavelength, the Sparker Acquisition System allows for deep penetration depths. Hence, the internal structure of the bedrock and overlying deposits, and its topography could be identified. Complemented by sedimentological data, an interpretation of subaqueous landforms (focus on underwater moraines) and their glacial formation was conducted. Based on their seismic facies and stratigraphic position, three main seismic units were defined (Figure 4c): Seismic unit I is the stratigraphically lowest unit. At some locations, it shows a large-scale layering, mainly dipping towards SE. Seismic unit II is stratigraphically located directly above unit I and shows chaotic to transparent seismic facies. Seismic unit III shows neatly layered, continuous reflections. Based on core-to-seismic data correlation and information from literature, seismic unit I could be assigned to bedrock material, seismic unit II to till, and seismic unit III to lacustrine sediments.

In the northwestern part of the lake, a N-S striking ridge could be identified in the bathymetric and seismic data (“Kreuztrichter ridge”; Figure 4). Previous studies have assumed this ridge structure to be mainly a depositional feature, namely a moraine [45]. However, the seismic reflection data clearly shows that the ridge is mainly a sill in the Molasse bedrock, as indicated by the SE dipping large-scale reflections, the same direction as the terrestrial outcrops of the Subalpine Molasse in the region [46]. However, the southern and northern parts of the ridge are covered by till, so the Molasse ridge may have favoured a stillstand of the glacier during its retreat and the deposition of till to create a moraine. The ca. 90 m deep trough in the Molasse bedrock cannot be identified from the bathymetric data alone, it is only visible in the seismic reflection data. The trough has a ca. 10-m-thick till base layer, which is covered by ca. 80-m-thick lacustrine sediments of the Holocene. Its location, typical “U” shape, and infill stratigraphy suggest that this trough was created by glacial activity.

4. Discussion

The aim of this work was to showcase three examples of landforms and structures that transition from the onshore to the offshore zone and to demonstrate the importance of combining DEMs and DBMs for geomorphological applications. Rather than conducting an exhaustive analysis of each landform, the goal was to provide an overview that highlights the potential of this integrated approach.

The availability of modern high-resolution bathymetric and seismic reflection data significantly enhances our understanding of the submerged landforms. Without these advanced acquisition techniques, many of these features would remain undetected. Both erosional and depositional structures that continue from the terrestrial to the aquatic environment could be identified in high-resolution geophysical data. The landforms presented in this article are the result of complex processes, including tectonic, glaciological, and dynamic influences (e.g., gravitational mass movements). The landforms can be eroded differently, due to varying weathering processes occurring in distinct environments. Whereas in the subaerial environment, physical erosion processes are favoured by rapid temperature changes and wind action, subaqueous weathering depends mostly on chemical and biological processes. However, wave action in shallow areas and currents can also contribute to erosion. Slow deposition of authigenic lacustrine sediments may protect landforms from erosion, although it may also obscure their original form. In some cases, it can be more difficult (or even impossible) to identify both terrestrial and subaqueous counterparts of a landform, due to various erosional, depositional, or anthropogenic processes that alter their morphology and surface features, as seen in the case where smoothing occurs due to authigenic and allogenic sediments.

By integrating various hydroacoustic survey data, such as seismic reflection data from the lake bottom with bathymetric data, it is possible to reveal not only what lies beneath the water surface but also what is hidden below the lake floor. The example of the Kreuztrichter ridge in Lake Lucerne highlights the importance of using a multi-method approach when investigating landforms.

The examples presented here demonstrate that an integrated analysis of terrestrial and subaqueous geophysical data – including DEMs, DBMs, and seismic reflection data – leads to a deeper understanding of landforms transitioning from subaerial to subaqueous environments. Knowing what landforms exist in an area and interpreting what processes were responsible for their formation may be very important for various applications, including sediment dynamics, slope stability analyses, and hydrodynamic investigations. Ultimately, the gained knowledge may contribute to better estimating and mitigating natural hazards (e.g., gravitational mass movements) both above and below lake level. This is of primary importance since geohazards do not stop at the lake shore, in contrast, they can trigger cascading hazards such as impulse waves or lake tsunamis. The mass-movement-generated tsunami potential on perialpine lakes mainly depends on the topography, bathymetry, potentially mobile sediment or rock volumes, and their respective location above or below lake level. A comparison of the tsunami potential for Swiss perialpine lakes can be found in [6].

Future research may adopt a more quantitative approach to further differentiate the effects of subaerial and subaqueous environments on specific landforms.

5. Conclusions

Whereas geomorphic mapping is often limited to either the subaerial or the subaqueous domain, conducting an integrated analysis of the landforms in a hybrid environment is highly recommended. Complementing investigations of subaerial landforms provide several significant benefits that enhance our geomorphodynamic understanding. An integrated approach for investigating nearshore subaerial and subaqueous geomorphologies is a first, but significant, step for estimating and mitigating geohazards.

Funding: This research received no external funding

Acknowledgments: The editor and the two anonymous reviewers are acknowledged for their constructive input.

Conflicts of Interest: The author declares no conflict of interest.

References

  1. Schnellmann M, Anselmetti FS, Giardini D, McKenzie JA. 15,000 Years of mass-movement history in Lake Lucerne: Implications for seismic and tsunami hazards. Eclogae Geologicae Helvetiae. 2006;99(3):409–428. doi:10.1007/s00015-006-1196-7
  2. Strasser M, Hilbe M, Anselmetti FS. Mapping basin-wide subaquatic slope failure susceptibility as a tool to assess regional seismic and tsunami hazards. Marine Geophysical Research. 2011;32(1–2):331–347. http://link.springer.com/10.1007/s11001-010-9100-2. doi:10.1007/s11001-010-9100-2
  3. Hilbe M, Anselmetti FS, Eilertsen RS, Hansen L, Wildi W. Subaqueous morphology of Lake Lucerne (Central Switzerland): Implications for mass movements and glacial history. Swiss Journal of Geosciences. 2011;104(3):425–443. doi:10.1007/s00015-011-0083-z
  4. Strupler M, Danciu L, Hilbe M, Kremer K, Anselmetti FS, Strasser M, Wiemer S. A subaqueous hazard map for earthquake-triggered landslides in Lake Zurich, Switzerland. Natural Hazards. 2018;90(1):51–78. http://link.springer.com/10.1007/s11069-017-3032-y. doi:10.1007/s11069-017-3032-y
  5. Tolotti M, Dubois N, Straile D, Lami A. Large and deep perialpine lakes : a paleolimnological perspective for the advance of ecosystem science. Springer International Publishing; 2018. https://doi.org/10.1007/s10750-018-3677-x. doi:10.1007/s10750-018-3677-x
  6. Strupler M, Evers FM, Kremer K, Cauzzi C, Bacigaluppi P, Vetsch DF, Boes RM, Fäh D, Anselmetti FS, Wiemer S. A Simplified Classification of the Relative Tsunami Potential in Swiss Perialpine Lakes Caused by Subaqueous and Subaerial Mass-Movements. Frontiers in Earth Science. 2020;8. https://www.frontiersin.org/article/10.3389/feart.2020.564783/full. doi:10.3389/feart.2020.564783
  7. Kremer K, Wirth SB, Reusch A, Fäh D, Bellwald B, Anselmetti FS, Girardclos S, Strasser M. Lake-sediment based paleoseismology: Limitations and perspectives from the Swiss Alps. Quaternary Science Reviews. 2017;168:1–18. http://www.sciencedirect.com/science/article/pii/S0277379117303542. doi:10.1016/j.quascirev.2017.04.026
  8. Strupler M. Mapping and interpreting subaquatic moraines in Lake Lucerne [MSc Thesis]. University of Zurich; 2012.
  9. Hilbe M, Strupler M, Hansen L, Eilertsen RS, Van Daele M, De Batist M, Anselmetti FS. Moraine ridges in fjord-type, perialpine Lake Lucerne, central Switzerland. Geological Society, London, Memoirs. 2016;46(1):69–70. http://mem.lyellcollection.org/lookup/doi/10.1144/M46.107. doi:10.1144/M46.107
  10. Fabbri SC, Haas I, Kremer K, Motta D, Girardclos S, Anselmetti FS. Subaqueous geomorphology and delta dynamics of Lake Brienz (Switzerland): implications for the sediment budget in the alpine realm. Swiss Journal of Geosciences. 2021;114(1):1–17. https://doi.org/10.1186/s00015-021-00399-1. doi:10.1186/s00015-021-00399-1
  11. Girardclos S, Schmidt OT, Sturm M, Ariztegui D, Pugin A, Anselmetti FS. The 1996 AD delta collapse and large turbidite in Lake Brienz. Marine Geology. 2007;241(1–4):137–154. doi:10.1016/j.margeo.2007.03.011
  12. Hilbe M, Anselmetti FS. Signatures of slope failures and river-delta collapses in a perialpine lake (Lake Lucerne, Switzerland). Sedimentology. 2014;61(7):1883–1907. doi:10.1111/sed.12120
  13. Schnellmann M, Anselmetti FS, Giardini D, McKenzie JA. Mass movement-induced fold-and-thrust belt structures in unconsolidated sediments in Lake Lucerne (Switzerland). Sedimentology. 2005;52(2):271–289. doi:10.1111/j.1365-3091.2004.00694.x
  14. Kremer K, Hilbe M, Simpson G, Decrouy L, Wildi W, Girardclos S. Reconstructing 4000 years of mass movement and tsunami history in a deep peri-Alpine lake (Lake Geneva, France-Switzerland). Sedimentology. 2015:1305–1327. doi:10.1111/sed.12190
  15. Strupler M, Anselmetti FS, Hilbe M, Strasser M. Quantitative characterization of subaqueous landslides in Lake Zurich (Switzerland) based on a high-resolution bathymetric dataset. Geological Society, London, Special Publications. 2019;477(1):399–412. http://sp.lyellcollection.org/lookup/doi/10.1144/SP477.7. doi:10.1144/SP477.7
  16. Reusch A, Moernaut J, Anselmetti FS, Strasser M. Sediment mobilization deposits from episodic subsurface fluid flow-A new tool to reveal long-term earthquake records? Geology. 2016;44(4):243–246. doi:10.1130/G37410.1
  17. Strasser M, Monecke K, Schnellmann M, Anselmetti FS. Lake sediments as natural seismographs: A compiled record of Late Quaternary earthquakes in Central Switzerland and its implication for Alpine deformation. Sedimentology. 2013;60(1):319–341. http://doi.wiley.com/10.1111/sed.12003. doi:10.1111/sed.12003
  18. Reusch A, Loher M, Bouffard D, Moernaut J, Hellmich F, Anselmetti FS, Bernasconi SM, Hilbe M, Kopf A, Lilley MD, et al. Giant lacustrine pockmarks with subaqueous groundwater discharge and subsurface sediment mobilization. Geophysical Research Letters. 2015;42(9):3465–3473. doi:10.1002/2015GL064179
  19. Cojean ANY, Kremer K, Bartosiewicz M, Fabbri SC, Lehmann MF, Wirth SB. Morphology, Formation, and Activity of Three Different Pockmark Systems in Peri-Alpine Lake Thun, Switzerland. Frontiers in Water. 2021;3(August):1–13. doi:10.3389/frwa.2021.666641
  20. Anselmetti F, Hilbe M. Tsunamis im Vierwaldstättersee. In: Die Natur kennt keine Katastrophen. 2016. p. 67–79.
  21. Hilbe M, Anselmetti FS. Mass Movement-Induced Tsunami Hazard on Perialpine Lake Lucerne (Switzerland): Scenarios and Numerical Experiments. Pure and Applied Geophysics. 2015;172(2):545–568. doi:10.1007/s00024-014-0907-7
  22. Kremer K, Fabbri SC, Evers FM, Schweizer N, Wirth SB. Traces of a prehistoric and potentially tsunamigenic mass movement in the sediments of Lake Thun (Switzerland). Swiss Journal of Geosciences. 2022;115(1). https://doi.org/10.1186/s00015-022-00405-0. doi:10.1186/s00015-022-00405-0
  23. Strupler M, Hilbe M, Kremer K, Danciu L, Anselmetti FS, Strasser M, Wiemer S. Subaqueous landslide-triggered tsunami hazard for Lake Zurich, Switzerland. Swiss Journal of Geosciences. 2018;111(1–2):353–371. http://link.springer.com/10.1007/s00015-018-0308-5. doi:10.1007/s00015-018-0308-5
  24. Kremer K, Marillier F, Hilbe M, Simpson G, Dupuy D, Yrro BJF, Rachoud-Schneider A-M, Corboud P, Bellwald B, Wildi W, et al. Lake dwellers occupation gap in Lake Geneva (France–Switzerland) possibly explained by an earthquake–mass movement–tsunami event during Early Bronze Age. Earth and Planetary Science Letters. 2014;385:28–39. http://linkinghub.elsevier.com/retrieve/pii/S0012821X1300527X. doi:10.1016/j.epsl.2013.09.017
  25. Kremer K, Simpson G, Girardclos S. Giant Lake Geneva tsunami in ad 563. Nature Geoscience. 2012;5(November):756–757.
  26. Swisstopo. swissTLM3D. https://www.swisstopo.admin.ch/en/landscape-model-swisstlm3d
  27. Swisstopo. DHM25. https://www.swisstopo.admin.ch/en/height-model-dhm25
  28. Swisstopo. SwissBATHY3D. https://www.swisstopo.admin.ch/en/height-model-swissbathy3d
  29. Swisstopo. SwissALTI3D. https://www.swisstopo.admin.ch/en/height-model-swissalti3d
  30. Swisstopo. GeoCover. https://www.swisstopo.admin.ch/en/geological-model-2d-geocover
  31. Swisstopo. GeoMaps 500. https://www.swisstopo.admin.ch/en/geomaps-500-vector
  32. Rouault E, Warmerdam F, Schwehr K, Kiselev A, Butler H, Łoskot M, Szekeres T, Tourigny E, Landa M, Miara I, et al. GDAL. 2024. https://doi.org/10.5281/zenodo.13330875. doi:10.5281/zenodo.13330875
  33. QGIS.org. QGIS Geographic Information System. 2024. http://qgis.org
  34. Morgan-Wall T. rayshader: Create Maps and Visualize Data in 2D and 3D. 2024. https://cran.r-project.org/package=rayshader
  35. R Core Team. R: A Language and Environment for Statistical Computing. 2024. https://www.r-project.org/
  36. Global S. Kingdom seismic and geological interpretation software. https://www.spglobal.com/commodityinsights/en/ci/products/kingdom-seismic-geological-interpretation-software.html
  37. Swisstopo. Swiss Map Raster 25. https://www.swisstopo.admin.ch/en/national-map-swiss-map-raster-25
  38. Gorin GE, Signer C, Amberger G. Structural configuration of the western Swiss Molasse Basin as defined by reflection seismic data. Eclogae Geologicae Helvetiae. 1993;86(3):693–716.
  39. Sastre V, Loizeau JL, Greinert J, Naudts L, Arpagaus P, Anselmetti F, Wildi W. Morphology and recent history of the Rhone River Delta in Lake Geneva (Switzerland). Swiss Journal of Geosciences. 2010;103(1):33–42. doi:10.1007/s00015-010-0006-4
  40. Keller B. Massive rock slope failure in Central Switzerland: history, geologic–geomorphological predisposition, types and triggers, and resulting risks. Landslides. 2017;14(5):1633–1653. http://link.springer.com/10.1007/s10346-017-0803-1. doi:10.1007/s10346-017-0803-1
  41. Huber A. Felsbewegungen und Uferabbrüche an Schweizer Seen, ihre Ursachen und Auswirkungen. Eclogae Geol. Helv. 1982;75(3):563–578. doi:10.5169/seals-165242
  42. Fuchs H, Boes R. Berechnung felsrutschinduzierter Impulswellen im Vierwaldstättersee. Wasser Energie Luft. 2010;102(3):215–221. doi:10.3929/ethz-b-000256996
  43. Pfiffner OA. Geologie der Alpen. Stuttgart, Deutschland: utb GmbH; 2015. https://elibrary.utb.de/doi/book/10.36198/9783838586106. doi:10.36198/9783838586106
  44. Frey-Martínez J, Cartwright J, James D. Frontally confined versus frontally emergent submarine landslides: A 3D seismic characterisation. Marine and Petroleum Geology. 2006;23(5):585–604. http://linkinghub.elsevier.com/retrieve/pii/S0264817206000341. doi:10.1016/j.marpetgeo.2006.04.002
  45. Buxtorf A, Tobler A, Niethammer G, Baumberger E, Arbenz P, Staub W. Geologische Vierwaldstättersee-Karte, 1:50000. Spezialkarte Nr. 66a. 1916.
  46. Hantke R. Blatt 1151 Rigi, mit Nordteil von Blatt 1171 Beckenried. – Geol. Atlas Schweiz, Erläut. 116. 2006.

This article has been published in European Geologist Journal 58 – Water – making the invisible visible

Read here the full issue: