Alaska Park Science 18(1):6-15. Dufresne, A., M. Geertsema, D. H. Shugar, M. Koppes, B. Higman, P. J. Haeussler, C. Stark et al. The 2015 landslide and tsunami reshaped the landscape at the terminus of Tyndall Glacier. 2017). In Grönland löste ein Erdrutsch an der Westküste im Jahr 2017 eine über 90 Meter hohe Welle aus , die einen Großteil eines nahe gelegenen Fischerdorfes zerstörte und vier Menschen tötete. Erosion rates during rapid deglaciation in Icy Bay Alaska. Ideally, new development in areas of potential tsunami inundation could be designed to maximize options for evacuation and minimize costs of reconstruction after an event. It is possible to anticipate areas of potential hazard for vessels using tsunami models. Finally, in troughs between waves vessels might ground on obstacles that would otherwise pose no threat. Where there was little loose sediment, the tsunami typically scoured the land down to bedrock, and left little in the way of deposits. Initial estimates of the maximum tsunami run up were as high as 150 m using the Alaska IfSAR-derived DEM. The careful documentation of the physical environment of the fjord before and after the landslide, combined with tsunami runup and flow directions, should make this a place where tsunami modelers can test their models to see if they work correctly. Journal of Sedimentology 364: 302-318. Glacial landslides, or glacial detachments, are a phenomenon of a warming planet. The Taan Fiord tsunami can help us understand subaerial landslide tsunami hazards and prepare for potential impacts. Precursory deformation began decades before failure, and the event left a distinct sedimentary record, showing that geologic evidence can help understand past occurrences of similar events, and might provide forewarning. 2009. Die Flutwelle scheint gewaltige Ausmaße gehabt zu haben. Haeussler, P. J., S. P. S. Gulick, N. McCall, M. Walton, R. Reece, C. Larsen, D. H. Shugar, M. Geertsema, J. G. Venditti, and K. Labay. VIDEO: Camp Bay, height Tyndall Glacier, Taan Fjord Mega-Tsunami. Auch die Zunge des Tyndall-Gletschers, der in den Taan-Fjord entwässert, wurde von Wasser und Gestein überflutet. See more pictures of Tyndall Glacier here: Go to Tyndall Glacier. In the case of Taan Fjord, the result was a massive tsunami," said Dr Dan Shugar, assistant professor of Geoscience at the University of Washington Tacoma and co-author of the report. Adventure kayakers, trophy bear hunters, commercial and sport fishers, and even cruise ships visit Icy Bay (Figure 2). Multibeam sonar and sub-bottom profiling show blocky deposits capped by more homogenous layered deposits filling the fjord bottom (Haeussler et al. Assuming these trees were originally circular in cross-section, some must have lost at least 4 inches (10 cm) of wood to achieve the scoured shape we observed. That tsunami contributed to the deaths of two people. Geomorphology 78: 207–221. Though logging along its shore has ended, plans for a large-scale mine are being explored, potentially creating another vulnerable facility. Der Tsunami wälzte sich bis in die eigentliche Bucht und rasierte auf seinem Weg das mit Tannen bestandene Ufer kahl. in The First Meeting of International Consortium of Landslides Cold Region Landslides Network, Harbin, China 49–54. On October 17th, 2015 a landslide adjacent to the tidewater Tyndall Glacier, located at the head of Taan Fjord in Alaska's Icy Bay, generated a massive tsunami that inundated and modified several large stream deltas within the fjord. Also, while modeled tsunami runup has been widely validated, currents produced by tsunami flows are rarely directly documented, and tsunami models differ substantially in the results they produce (Lynett et al. Observations and modeling of tsunami-induced currents in ports and harbors. The black arrows show only the direction of the moving water; together with the color the viewer is able to see both the magnitude and direction of the tsunami flow. The October 17th, 2015 Taan Fiord landslide and tsunami generated a runup of 193 m, nearly an order of magnitude greater than most previously surveyed tsunamis. They can impact areas as large as entire ocean basins, but with shorter runups (they run up from the coast to lower elevations), as happened with the Indian Ocean tsunami in 2004, and the Tohoku, Japan tsunami in 2011. Ground Truth Trekking, licensed under CC BY 3.0 . In Alaska stürzten 2015 am Taan Fjord enorme Gesteinsmassen ins Meer. 2013. F2. The October 17th, 2015 Taan Fiord landslide and tsunami generated a runup of 193 m, nearly an order of magnitude greater than most previously surveyed tsunamis. In October 2015, a massive landslide slid into Taan Fjord and created a tsunami in excess of 600 feet. While most of the Taan landslide debris entered the fjord, in other cases, the percentages of debris deposited in water bodies may be minimal to non-existent. The slide caused tens of meters of shallowing in some areas, while it eroded sections of the pre-landslide shoreline. The 2015 landslide and tsunami reshaped the landscape at the terminus of Tyndall Glacier. In contrast, one small island that used to support supra-tidal vegetation was scoured down such that now it is only a shoal emerging at low tide (location marked on Figure 5). Die daraus resultierende Welle war bis zu 193 Meter hoch Note how the tsunami is strongly influenced by the topography, with large changes in run-up elevations over short distances. Bourgeois, J. 2018), and as glaciers continue to migrate landwards, water bodies such as fjords and lakes will also grow landward toward steep, recently deglaciated terrain, increasing the potential for more landslides, more “direct hits” into water, and therefore more, and possibly larger landslide-generated tsunamis. Global Historical Tsunami Database. 2018. It is a unique event in that the landslide debris was deposited into three very different environments: on the glacier surface, on land, and in the marine waters of the fjord. 1960. Additionally, glacial retreat is exposing new bodies of water that may be vulnerable to tsunamis. Ground Truth Trekking, licensed under CC BY 3.0. Journal of Geophysical Research 111 no. Sedimentology and geomorphology of a large tsunamigenic landslide, Taan Fiord, Alaska. Scientific Reports 8: 12993. A systematic analysis of this sort could inform park development planning and public education efforts that could reduce risk. At the same time, glaciers fill the valley, preventing failure of lower slopes and supporting higher slopes to reduce the chance of slope collapse. Earth and Planetary Science Letters 327-328:68-74. Tsunamis generated by subaerial landslides are often confined to a few tens of kilometers around the landslide, both because shorter-period waves disperse energy more quickly and because they commonly are triggered in relatively confined bays and lakes. The tsunami moved boulders up to 16 feet (5 m) in diameter where it was largest (Figure 3). Though landslides like this can happen at any time, these events are becoming more frequent—driven by climate change-induced glacial retreat and permafrost thaw. The degree of destruction increased away from the limit of inundation, areas 60 feet (20 m) below that limit were typically so hard-hit that only a few torn roots and soil remnants remained, while trees near the limit were often toppled but still rooted. Wiles, G. C. and P. E. Calkin. Climate change has increased the risk of a huge landslide in an Alaskan fjord that could cause a catastrophic tsunami, scientists said Thursday. Approximately 90% of the landslide entered the fjord, generating a tsunami. Some of the rock slid onto the snout of a tidewater glacier but most slid into the head of Taan Fjord – displacing a massive volume of water. 1992. More recently, a 2015 landslide near Alaska’s Taan Glacier produced a 633 feet (193 meter) wave in Taan Fjord that smashed into the opposite wall of the glacial valley. “Earlier, we … An 800 foot (250 m) diameter hill that was surrounded but not overtopped by the tsunami had runups of over 160 feet (50 m) where the tsunami directly impacted it, but less than 65 feet (20 m) on the lee side (Figure 5). Both of these events thankfully occurred in sparsely populated areas, so few fatalities occurred. The Journal of Geology 1: 3. Photo: Ground Truth Alaska (CC BY-NC 3.0) Responding to this May’s warning, Chugach National Forest officials advised the public to avoid the famously scenic Harriman Fiord, a staple for recreation and tourism activity that provides revenue across south-central Alaska. The Sea 15: 53–91. 2018. Geophysical Research Letters 44: 7276–7284. Taan Fjord is on the east side of Icy Bay, about 14 miles (22 km) north-northeast of Point Riou. Die Folge war ein Tsunami mit knapp 200 Meter Höhe. The wave affected the entire length of the fjord. And in 2017, a landslide in Greenland produced a tsunami that roared into a small, isolated community. A small volume of the total slide mass remains within the source area and is topped by striated blocks (> 10 m across) and standing trees that were transported down the slope in intact positions during the landslide. Simple scaling of catastrophic landslide dynamics. July 15, 2020. The 2015 Taan Fiord landslide and tsunami. The 2015 Taan Fjord tsunami was generated by a 99 million cubic yards (76 million cubic meters) landslide that occurred following retreat of the Tyndall Glacier. In October 2015, a massive landslide slid into Taan Fjord and created a tsunami in excess of 600 feet. The Taan Fiord event provides warning that Icy Bay may see similar, potentially more deadly events in the future. Tsunamis are water waves generated by a sudden force (Bourgeois 2009), typically through either rapid displacement of the seafloor (during earthquakes or from submarine landslides), or through displacement and impact (by mountain landslides entering water, glacial ice collapses, or meteorite impacts). Sie schickte eine Tsunamiwelle, die 193 m hoch an den gegenüberliegenden Talhängen aufprallte. However, many similar situations might have had greater impact: A landslide might occur at a busy time of year; a small landslide or tsunami might impact a beach campsite; or a large landslide might occur in one of the other fjord arms of Icy Bay. Alaska parks are prone to events like this. Geologic effects and records of tsunamis. To date, most post-tsunami surveys are from earthquake-generated tsunamis and the geomorphic signatures of landslide tsunamis or their potential for preservation are largely uncharacterized. Tree trunks that remained standing after the tsunami were scoured by strong sediment-laden currents that sometimes severely abraded the upstream side of trees, leaving them peppered with small rocks (Figure 3). Landsat 8 image of Taan Fiord acquired in 2016. In the case of the massive landslide that fell into Taan Fjord, Alaska, the answer was no—and yes. Part of the debris traversed the width of the fjord and re-emerged onto land, depositing coherent hummocks with preserved source stratigraphy on an alluvial fan and adjacent moraines on the far side of the fjord. Smaller vessels might experience some of the same hazards as can be found in tidal rapids—strong eddy-lines and whirlpools that can capsize and sink boats. Our field observations provide a benchmark for modeling landslide and tsunami hazards. 2019. Icy Bay [near Taan Fjord] was full of glaciers as recently as 100 years ago.” A giant boulder moved by the tsunami as it ran down Taan Fjord. When they retreat, whether due to changing climate or to regular glacial cycles, they remove that support, allowing slopes to sag and fractures to expand, making them vulnerable to failure. A., E. K. Bessette-Kirton, and M. Geertsema. The most dramatic hazard posed to vessels is the breaking tsunami wave in areas where the tsunami height is significant in comparison to the depth of the water. The colors on the tsunami indicate the height, with the reds indicating tsunami crest elevations of 40 m (130 ft) above the tide and the dark blues showing tsunami trough depressions of 20 m (65 ft) below the tide level. Climate warming is likely driving an increase in the frequency of large landslides and promoting the growth of deep bodies of water where large tsunamis can form. CoastView. October 1, 2020 - by Tim Lydon. Landslides doi:10.1007/s10346-017-0879-7 A small portion of the landslide traveled across the fjord bottom and slid back up above the waterline on the far side of the fjord, forming 30-70 feet-high (10-20 m) debris hillocks. Oktober 2015 kamen 180 Millionen Tonnen Fels plötzlich ins Rutschen. 11. Days later, high-resolution satellite imagery revealed the landslide and tsunami impacts, and tide gage data from more than 90 miles (~150 km) away at Yakutat showed small fluctuations in water level (4 inches or ~0.1 m) resulting from the tsunami. The Icy Bay landslide in Alaska. Most of the research on tsunami impacts has focused on longer-period regional tsunamis—especially subduction zone earthquake tsunamis that produce some of the longest period waves. 2018. A few sites showed that hills can provide significant protection from the worst tsunami impacts. “The resulting tsunami reached elevations of … Am 17. In ... Taan Fjord, Alaska, USA: Fjord: subaerischer Erdrutsch: 193 → Tyndall-Gletscher: 1936: Lituya Bay, Alaska, USA: Fjord: subaerischer Erdrutsch: 149: 2017: Nuugaatsiaq, Grönland: Fjord : subaerischer Erdrutsch: 90 → Tsunami in Grönland 2017: Einzelnachweise. Current velocity validation using natural indicators of previous tsunami flow, or using direct observations of tsunamis, are badly needed. At 8:19 p.m. Alaska Daylight Time on 17 October 2015, the side of a mountain collapsed on the western end of the head of Taan Fiord, a finger of Icy Bay. The looming tsunami of Harriman Fjord A century ago, Icy Bay was filled with glaciers (Russel 1893). Der Erdrutsch ihm Taan Fjord (einem Seitenarm des von Touristen oft besuchtem ‘Icy Bay’) verlief nicht viel anders. A decade before catastrophic failure in 2015, Meigs and others (2006) noted ground-cracking and deformation, and aerial topographic surveys documented tens of meters of gradual motion (Higman et al. September 2018, 08:00 57 Postings. Lituya Bay produced at least five giant tsunamis over the course of three centuries (Miller 1960) and Icy Bay could well rack up a similar record. 2018. Tyndall Glacier flows to the head of Icy Bay, about 160 miles (258 km) east-southeast of Cordova and 68 miles (110 km) northwest of Yakutat, Alaska. Furthermore, at higher elevations and in arctic and subarctic climates, permafrost is a significant contributor to the strength of some mountains, and thawing, or even warming of still-frozen permafrost, can greatly weaken those mountains. These impacts in Taan Fiord show that development should be sited outside areas of anticipated inundation, and evacuation routes are needed so that anyone within the flood zone can effectively flee. Mt. The rapid retreat of the glacier destabilized the steep slopes of the surrounding mountains and a massive landslide occurred on October 17, 2015. Taan Fjord is remote, but the Tidal Fjord in tourist-heavy Glacier Bay, Alaska, saw a landslide in June 2016. Inverse and forward modeling can provide the framework of a detailed understanding of the geologic and hazards implications of similar events. On 17 October 2015, a landslide of roughly 60 × 106 m3 occurred at the terminus of Tyndall Glacier in Taan Fiord, southeastern Alaska. ... a 2015 landslide at Taan Fjord … Figure 4 shows the 2012 Hubbard and Lituya landslides (Geertsema 2012). In October 2015, a 76 M m 3 section of unstable rock from the Daisy tributary catchment collapsed into Taan Fjord and partially onto the terminus of Tyndall Glacier (Fig. Visit our keyboard shortcuts docs for details, Next Chapter: Catastrophic Glacier Collapse and Debris Flow at Flat Creek, Previous Chapter: Geohazards in Alaska’s National Parks. Journal of Geophysical Research, Earth Surface DOI: 10.1029/2018JF004608. Large landslides are on the increase in southeast Alaska (Coe et al. Areas near stream deltas or other sediment sources might be buried by transported sediment. Tsunami impacts near the landslide. These collapsed fans left no clear deposit—presumably because they were incorporated into the moving submarine slide mass. 2018. Piles of earth and rock following the 2015 Taan Fjord landslide and tsunami. The impact of the slide with the water generated one of the tallest tsunami waves in historical times. 2006), a month of above-average rain, and a few seconds of mild shaking from a distant earthquake (Higman et al. Geomorphology 5: 535–546. 2018, Gullufsen 2018). “In Taan Fiord (Icy Bay, Alaska), a landslide that began moving slowly decades ago suddenly failed in October 2015. Tsunami-inducing landslides are rare but have occurred in Alaska and elsewhere. USGS scientists investigate trees knocked over by the tsunami at the mouth of Taan Fjord, Alaska. It triggered a tsunami wave with a runup height exceeding 90 m close to the landslide, ca. Tsunamis caused by earthquakes are typically long-period waves, meaning they rise and fall gradually. And in 2015, a landslide-generated tsunami in the Taan Fjord in Icy Bay, Alaska, caused a 300-metre run-up of water, says Synolakis. We are able to calculate the volume of the landslide and the volume that entered the fjord. Even though some of the Hubbard landslide entered Disenchantment Bay, it was only a small proportion of the distal landslide deposit—thus the wave was very small—overtopping the beach by less than 6 feet (2 m). A giant boulder moved by the tsunami that ran down Taan Fiord in 2015. Die daraus resultierende Welle war bis zu 193 Meter hoch . Der Felsabbruch im Jahr 2015 mit folgendem Tsunami in der Icy Bay Urheberrecht: A. Dufresne Abbildung 1. Fortunately, the debris from that event didn't reach the water, avoiding a tsunami. A structure built here or in analogous locations would likely fare better even than more exposed locations that are significantly farther from the tsunami source. Alaska’s parks could do a lot to be better prepared for future events like this, whether in Icy Bay or anywhere else where steep glaciated mountains rise above deep water. More recently, a 2015 landslide near Alaska’s Taan Glacier produced a 633 feet (193 meter) wave in Taan Fjord that smashed into the opposite wall of the glacial valley. Koppes, M. and B. Hallet. After the failure in 2015, a portion of the slide block remained on the slope, still covered by jumbled, but still largely upright alder forest (Dufresne et al. Gullufsen, K. 2018. Oktober 2015 landete ein Erdrutsch von rund 180 Millionen Tonnen Gestein auf der Zehe des Tyndall Glacier und im Wasser des Taan Fjords. Modeling based on potential sources can help outline areas of likely impact, with an emphasis on sites with known risk factors. In 2015 rutsche dort innerhalb von wenigen Minuten nach einem kleinem Erdbeben eine riesige Erdmasse ins Icy Bay (St. Elias Wrangell Mountain National Park) ab. (US Government Printing Office Washington, DC). Ground Truth Trekking, licensed under CC BY 3.0.

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