A recent string of massive landslides in Alaska and around the world bears the fingerprint of climate change. Not all Alaskan rockslides possess the same potential as the Taan Fiord event for generating giant waves that might endanger vessels. 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. This landslide-generated tsunami had a maximum height of over 600 feet. Ultra-rapid landscape response and sediment yield following glacier retreat Icy Bay, southern Alaska. Inversion of long-period waves arriving at nearby seismometers identified the general area and direction of the landslide. Some forest remained standing along steep slopes with runups of about 30 feet (10 m), and patches of dense spruce forest at the mouth of the fjord survived where rafts of debris formed dams to protect them from the iceberg-laden flow. National Geophysical Data Center, NOAA. And in 2017, a landslide in Greenland produced a tsunami that roared into a small, isolated community. In Alaska stürzten 2015 am Taan Fjord enorme Gesteinsmassen ins Meer. Figure 4 shows the 2012 Hubbard and Lituya landslides (Geertsema 2012). Months later, teams of scientists visited the site to document both the landslide and tsunami. 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. 2018. Adventure kayakers, trophy bear hunters, commercial and sport fishers, and even cruise ships visit Icy Bay (Figure 2). Having detected the Tyndall Glacier landslide, Stark and Ekstrom located it with a very high resolution satellite image, which Lamont-Doherty have included in their press release : Geologic effects and records of tsunamis. And in 2017, a landslide in Greenland produced a tsunami that roared into a small, isolated community. 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. Tyndall Glacier retreated at an increasing pace through the late 20th century until it stabilized in 1991, at approximately the location of the current terminus. The Icy Bay landslide in Alaska. Alaska Park Science 18(1):6-15. Die Flutwelle scheint gewaltige Ausmaße gehabt zu haben. Approximately 90% of the landslide entered the fjord, generating a tsunami. 2013. 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. 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. Higman, Bretwood, Dan H. Shugar, Colin P. Stark, Göran Ekström, Michele N. Koppes, Patrick Lynett, Anja Dufresne et al. Direkt neben dem Tyndall-Gletscher stürzten sie in die Tiefe und verdrängten abrupt das Wasser im Tal, wodurch sich eine gewaltige Flutwelle bildete. Am gegenüberliegenden Hang schlug sie 193 Meter empor. However, modeling to simulate possible future events will be very sensitive to potential landslide locations, requiring many model runs to capture a range of possible scenarios. The friction that held silt to silt and rock to rock began giving way. 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. Scientific Reports 8(1): 12993. doi:10.1038/s41598-018-30475-w The 2015 landslide and tsunami reshaped the landscape at the terminus of Tyndall Glacier. Some 200 million metric tons of rock slid down the mountain in a crash that must have been deafening. 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. These deposits are distinctive in their character, up to 70 m thick, and we anticipate that other such deposits should be recognizable in other fjords. 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 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. 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. These long-period tsunamis usually take up to a half-hour to inundate elevations less than twenty meters above the water. Journal of Geophysical Research, Earth Surface DOI: 10.1029/2018JF004608. (US Government Printing Office Washington, DC). The faint echo of the tsunami reached tide gages 80 and 250 miles (130 and 400 km) away where they recorded 40-minute-long oscillations of several inches in water level. 180 Millionen Tonnen Gestein donnerten damals in einen Fjord. Unlike during the Lituya Bay tsunami -- during which three anchored boats were sunk by or rode atop a 100-foot wall of water -- no fisherman were in Taan Bay at the time of the slide. 2018. Wiles, G. C. and P. E. Calkin. 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. Erosion rates during rapid deglaciation in Icy Bay Alaska. 2019. At the same time, glaciers fill the valley, preventing failure of lower slopes and supporting higher slopes to reduce the chance of slope collapse. 2018. Field work was carried out in the summer of 2016, and by the time this paper was written, almost all of the supraglacial debris was advected into the fjord and half the subaerial hummocks were buried by glacial advance; this rapid change illustrates how highly active sedimentary processes in high-altitude glacial settings can skew any landslide-frequency analyses, and emphasizes the need for timely field investigations of these natural hazards. 2006. 11. 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. September 2018, 08:00 57 Postings. 2009. Numerous landslides and at least two smaller landslide tsunamis have occurred in Alaska recent years (e.g., Geertsema 2012, Coe et al. They happen quickly and pose a threat to anything and everything in their path. Meigs, A., W. C. Krugh, K. Davis, and G. Bank. When the tsunami occurred in October 2015, workers were present in Icy Bay Lodge just 20 miles (32 km) away, fortunately beyond damaging waves. Using a variety of Digital Elevation Modeling (DEM) and imagery sources, the research team was able to estimate the landslide volume, document movement leading up to the event, and map the deposit thickness. Lynett, P., J. Borrero, R. Weiss, S. Son, D. Greer, and W. Renteria. Ekström, G. and C. P. Stark. It caused a tsunami that inundated an area over 20 km2, whereas the landslide debris itself deposited within a much smaller area of approximately 2 km2. Even below the inundation line on the protected side of this hill, there were more rooted trees and intact soil than in less-protected areas. Die daraus resultierende Welle war bis zu 193 Meter hoch . Taan Fjord is a long, and narrow fjord created by the retreat of the Tyndall glacier over the past 50 years The fjord is ~ 15 km in length, with depths to ~180 m The coastline along Taan is a mix of glacial moraines, alluvial fans, dense brush, and steep, barren slopes. The slide caused tens of meters of shallowing in some areas, while it eroded sections of the pre-landslide shoreline. VIDEO: Camp Bay, height 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). Two-and-one-half-miles (4 km) farther, on a section of the west coast of Icy Bay that faces directly toward the mouth of Taan Fiord, the wave reached 36 feet (11 m) and toppled trees, but quickly diminished to below high tide as it spread out along the coast (Figure 2). 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. Recent papers take a detailed look at the events leading up to and during one of the most massive landslide and tsunamis ever recorded. The articles call attention to the increasing frequency and magnitude of natural hazards near glaciated mountains and attributes these incidents, indirectly, to climate change. The area is uninhabited and no one was visiting it at the time, and the event went undetected for several hours until its signature was noted as a 4.9-magnitude event on the Richter scale on seismograms at Columbia University in New York City. 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. However, no such preparation was conducted and it’s urgent that we learn from the 2015 event and take steps to assess and mitigate hazards in Icy Bay and elsewhere before another event happens. Ground Truth Trekking, licensed under CC BY 3.0. 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. Vegetation loss is clear near the water line. The landslide flowed into Taan Fjord, triggering a localised tsunami that was detected 155 km away, according to the Lamont-Doherty press release. Climate Change. 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. The Tsunami Generated by the October 17th, 2015 Taan Fjord Landslide Patrick Lynett, Robert Weiss, Andrew Mattox, Vassilios Skanavis, Bretwood Higman, Adam Keen, Hui Tang, Colin Stark, Aykut Ayca Photo property of Bjørn Olson. 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. Slope failure at the terminus of Tyndall Glacier on 17 October 2015 sent 180 million tons of rock into Taan Fiord, Alaska. Der Tsunami hinterließ dicke, charakteristische Ablagerungen, die sich von denen anderer moderner Tsunamis 16 unterschieden, als er mehrere Schwemmfächer entlang des Taan-Fjords überschwemmte und wieder auftauchte (siehe ergänzende Abbildung). In October 2015, a massive landslide slid into Taan Fjord and created a tsunami in excess of 600 feet. In Taan Fiord, Alaska, we collected excellent postlandslide data of the Earth's surface, both above and below sea level. Imagery from before the landslide shows that the catastrophic slope failure was preceded by deformation and sliding for at least the two decades since the glacier retreated to its current terminus location, exposing steep and extensively faulted slopes. 50 m on the opposite shore of the fjord. Geomorphology 78: 207–221. Mt. In October 2015, a massive landslide slid into Taan Fjord and created a tsunami in excess of 600 feet. July 15, 2020. In some areas where there was abundant loose sediment, deposits of everything from boulders to sand were so thick that they raised ground elevations by over 16 feet (5 m). Nonetheless, the hazard from large landslide-generated waves will likely increase in the coming decades. In addition to the complete destruction in the path of the slide, the 2015 Taan Fiord landslide reshaped the fjord bottom and far shoreline. Also see this article in Alaska Park Science. 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. The Sea 15: 53–91. The events at Grewingk Lake, Taan Fiord, and a 2016 landslide tsunami in Cowee Creek near Juneau all occurred in bodies of water that didn’t exist (because their basins were filled with ice) only a few decades before. “The resulting tsunami reached elevations of … 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. 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. In most places, the forest was destroyed by the passing wave. The event was detected within hours through automated seismological techniques, which also estimated the mass and direction of the slide - all of which were later confirmed by remote sensing. They crash ashore more like a wind wave, rising to their peak elevations within a few minutes at most. Submarine deposition of a subaerial Landslide in Taan Fiord, Alaska. The landslide began as a rotational slide, likely following planes of weakness established decades earlier when failure initiated shortly after glacial retreat. USGS scientists investigate trees knocked over by the tsunami at the mouth of Taan Fjord, Alaska. The wave affected the entire length of the fjord. 2018. Areas near stream deltas or other sediment sources might be buried by transported sediment. The quick detection of this event, the existence of high quality pre-event topographic data, … 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. 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. 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. VIDEO: Camp Bay, velocity. Large landslides are on the increase in southeast Alaska (Coe et al. 2018. 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. After crossing the toe of Tyndall Glacier and entering the water, it generated a violent wave that flattened about eight square miles (20 km2) of forest in Wrangell-St. Elias National Park and Preserve and adjacent private lands (Figure 1). Gullufsen, K. 2018. More recently in 2015, a landslide in Taan Fjord sent roughly 10 million cubic yards of material tumbling into the waters of the remote area west of Yakutat, Alaska and caused a tsunami … DOI:10.1029/2005JF000349. Science 339: 1416–1419. 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. English: Changes in Taan Fiord. Russel, I. C. 1893. 2012. CoastView. However, most of the slide mass sped across the shoreline and terminus of Tyndall Glacier and entered Taan Fiord. The location shown here is near the mid-length of Taan Fiord, where the survey team set up their primary base camp. Landsat 8 image of Taan Fiord acquired in 2016. As it moved down the fjord, the wave stripped vegetation to varying heights that gradually diminished down-fjord. These results could then be compared to areas of infrastructure development, popular tourist destinations, and ship course data (e.g., from Automatic Identification System (AIS) ship-tracking systems) to identify areas of particular vulnerability. Ground Truth Trekking, licensed under CC BY 3.0. 2). See more pictures of Tyndall Glacier here: Go to Tyndall Glacier. A very nice video has been posted on Youtube describing the link between the giant Icy Bay landslide in Alaska in 2015 (this landslide is also variously known as the Taan Fjord landslide and the Tyndall Glacier landslide), which is the largest known recent landslide in North America, and the melting of the adjacent glacier. The tsunami travelled ca. The impact of the slide with the water generated one of the tallest tsunami waves in historical times.  On 9 July 1958, a 7.8 M w strike-slip earthquake in southeast Alaska caused 90 million tonnes of rock and ice to drop into the deep water at the head of Lituya Bay. 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. The location shown here is near the mid-length of Taan Fiord, where the survey team set up their primary base camp. Global Historical Tsunami Database. Depending on the geometry, size, and speed of this force, the nature of the resulting tsunami wave can vary dramatically. Additionally, some consideration should be given to sediment transport: rip rap boulders could be carried by a tsunami, increasing damage and recovery costs. 2018. Tyndall Glacier, Taan Fjord Mega-Tsunami. It wasn’t until the 1960s that four steep-walled fjords began to open at the head of the bay. doi:10.7289/V5PN93H7 The landslide flowed into Taan Fjord, triggering a localised tsunami that was detected 155 km away, according to the Lamont-Doherty press release. Taan Fjord is remote, but the Tidal Fjord in tourist-heavy Glacier Bay, Alaska, saw a landslide in June 2016. Like all tsunami waves, it would also be prone to breaking in shallow water. In the last century, 10 of the 14 highest tsunamis in the world were in glaciated mountains and four were in Alaska parks, which include vast tracts of glaciated terrain (Table 1). https://doi.org/10.1016/j.sedgeo.2017.10.004 Those first rocks shoved more rocks, and then more still. Much of the landslide material was deposited on the Tyndall Glacier and into the fjord. The 2015 landslide and tsunami in Taan Fiord, Alaska. Miller, D. J. Der Tsunami wälzte sich bis in die eigentliche Bucht und rasierte auf seinem Weg das mit Tannen bestandene Ufer kahl. Additionally, glacial retreat is exposing new bodies of water that may be vulnerable to tsunamis. English: Tsunami impacts near the landslide. Much of the landslide material was deposited on the Tyndall Glacier and into the fjord. Want more? in The First Meeting of International Consortium of Landslides Cold Region Landslides Network, Harbin, China 49–54. Tsunamis caused by earthquakes are typically long-period waves, meaning they rise and fall gradually. Presumably what little sediment was available in these areas was transported offshore. The landslide triggered an enormous local tsunami. Other fjords at the head of Icy Bay have steep slopes that haven’t yet been surveyed for potential landslide hazards. 2018). Malaspina Glacier.