are recognizable as the light areas rimming the bay. The tsunami reached 524 m above sea level on the opposite shoreline and killed two people in a small boat. Although there have been at least 90 M>4 earthquakes within 100 kilometers of Glacier Bay since 1958, none have been large or close enough to trigger landslides in the Park. The areas of destroyed forest along the shorelines... [+] are recognizable as the light areas rimming the bay. Gigantic waves will catch the intruder, transforming it into a bear, common animals in the Alaskan wilderness. The concerned experts claim the catastrophic event could even happen within the next 12 months if melting ice triggers a landslide of unstable rocks. A melting Alaska glacier could trigger an unprecedented ‘mega-tsunami,’ scientists have warned. Portions of the head and toe of the smaller Landslide B have shown a relatively small 3 inches of movement during the same period. The results indicate that Landslide A has shown little to no movement, with less than an inch of change. After scrutinizing the bay’s geology and history for years, one scientist calculated giant waves happen there once every quarter century—a 1 in 9000 chance on any given day. USGS scientists want to answer these questions: The USGS investigation determined where landslides could start and where they could travel within GBNPP. The landslide loosened some 40 million cubic yards of debris spawned a … “Although landslides occur in every State, our understanding of landslide hazards at the national scale is limited because landslide information across the United States is incomplete, varies in quality, accessibility, and extent, and what is known is not collected in a central location,” said Jonathan Godt, USGS program coordinator for Landslide Hazards. It’s unknown whether or not it created a tsunami, but its size makes it the largest known landslide within GBNPP. Satellite image of the Lituya Bay in Alaska. Rock avalanches are particularly dangerous because they involve large volumes of earth material, they can move long distances (>1 kilometer), and they can travel very fast (up to 100 meters per second). A "big wall of water," according to Ulrich 50 to 75 feet high, swept through the bay washing away rocks and trees along the shores. On the night of July 9, 1958, an earthquake along the Fairweather Fault in the Alaska Panhandle loosened about 40 million cubic yards (30.6 million cubic meters) of rock high above the northeastern shore of Lituya Bay. A typical tour of the Bay traverses the entire length of the Bay to the glacier calving viewpoints in the Johns Hopkins and Tarr Inlets. Juli 1958 verursachte ein Erdbeben einen Erdrutsch am östlichen Ende (landeinwärts gelegen), bei dem 90 Millionen Tonnen Gestein und Eis in die Bucht stürzten. More recently, in 2015, a rock avalanche in Wrangell-St. Elias National Park and Preserve about 300 kilometers northwest of GBNPP, travelled about 5 kilometers into Taan Fiord, and generated a tsunami that ran about 190 meters up the shoreline. Studying therefore old maps, photographs and reports, I became interested in the history of geology and how early geologists figured out how earth works, blogging about it in my spare time. Melting glaciers in Prince William Sound in Alaska could lead to a mega tsunami, scientists have said. It is a T-shaped bay with a width of 2 miles (3 km) and a length of 7 miles (11 km). In the confines of Glacier Bay, a locally generated tsunami could produce massive waves that slosh up the hillsides in bathtub fashion. The largest tsunami ever recorded occurred in 1958 in Lituya Bay, Alaska, per the United States Geological Survey. Existing digital data on landslide occurrence are held by a range of Federal, State, and local government agencies, and no central point of access has previously been available. A century-long glacial retreat has opened a multi-armed bay more than 30 miles (48 km) long. EY & Citi On The Importance Of Resilience And Innovation, Impact 50: Investors Seeking Profit — And Pushing For Change, Michigan Economic Development Corporation BrandVoice. Is the unstable slope in Barry Arm moving now? The landslide and tsunami occurred within Taan Fiord, and fortunately didn’t impact any structures. © 2020 Forbes Media LLC. Living in one of the classic areas of early geological research, I combine field trips with the historic maps, figures and research done there. Trees washed away be the wave along the slopes of the Gilbert Inlet, on the opposite shore, suggests a maximum wave height of 1,720 feet, taller than the Empire State Building in New York. Tsunami-inducing landslides are rare but have occurred in Alaska and elsewhere. At the beginning of the 20th century, the bay entrance was permanently blocked by a giant tidewater glacier face that calved icebergs directly into the Gulf of Alaska. Der wohl spektakulärste Mega-Tsunami dieser Art ereignete sich im Jahr 1958 in der Lituya Bay, einer T-förmigen Bucht von 11 km Länge und 1.3 km Breite im Glacier Bay National Park an der südlichen Ostküste Alaskas. With increased effects of climate change predicted for the future, it is important to investigate the potential impacts to landslide hazards and any associated risks to park visitors. Yellow dots show how high the tsunami reached above water level (runup) in meters. I graduated in 2007 with a project studying how permafrost, that´s frozen soil, is reacting to the more visible recent changes of the alpine environment. French explorer Jean-François de La Pérouse who explored Alaska in 1786, noted that the shores of Lituya Bay "had been cut cleanly like with a razor blade," suggesting that a tsunami occurred shortly before his arrival. Areas with the most potential for landslides entering the water (where they could possibly generate waves that could affect boats) are the Johns Hopkins, Tarr, Rendu, and Tidal Bay Inlets. The narrow entrance of the bay has a depth of only 33 feet (10 m). The tsunami reached 524 m above sea level on the opposite shoreline and killed two people in a small boat. In 1958, a landslide into Alaska’s Lituya Bay created a 524-meter wave – the tallest ever recorded. The Lituya Bay earthquake was powerful enough to generate a series of smaller landslides, both in the sea as on land, at a distance of 155 miles from the quake epicenter. In collaboration with State geological surveys and other Federal agencies, the USGS has compiled much of the existing landslide data into a searchable, web-based interactive map called the U.S. I graduated in 2007 with a project studying how permafrost, that´s frozen soil, is reacting to the more. Since 1853 at least four or five similar events are documented. Die entstehenden Felsstürze bedecken Gebiete zwischen 5,5 und 22,2 Kubikkilometern. The tsunami did have some impact outside the fjord, but did not reach coastal habitations. In 2018, the National Park Service (NPS) article “Landslides and Giant Waves” said, “The combination of recent deglaciation, relatively frequent earthquakes, steep rocky slopes, and narrow inlets suggests that many locations in Glacier Bay have the potential for generating large tsunami waves” that could pose a threat to ships or boats nearby. Lituya Bay, on the west side of the park (part of Glacier Bay National Monument in 1958), has experienced at least 3 tsunamis, the largest occurring in 1958 from an M7.8 earthquake on the Fairweather fault that triggered a rockslide. Based on this initial investigation, USGS scientists recommended more fieldwork to determine geologic conditions that control landslide occurrence and size, systematic monitoring of steep slopes to detect slow movements or deformations that could possibly provide warning of landslide events, and tsunami modeling to determine the boat size that could be threatened by landslide-generated waves. Im Glacier Bay National Park in SE Alaska sind laut unseren Kollegen Coe et al. Geological evidence, historical observations, and even myths suggest that such megatsunami are quite common along the Gulf Of Alaska. Lituya Bay a few weeks after the 1958 tsunami. Still, Alaskans should understand the risk and follow advice from emergency managers to prepare for a tsunami in the unlikely event that one occurs. All Rights Reserved, This is a BETA experience. (2018) seit 1984 mindestens 24 große Felsstürze aufgetreten. However, there is no evidence a significant failure is imminent, or that one will happen anytime soon. A giant, catastrophic tsunami in Alaska triggered by a landslide of rock left unstable after glacier melting is likely to occur in the next two decades, scientists fear - and it could happen within the next 12 months. Local legends record even earlier events, predating modern explorers and scientists by centuries. Icy Bay, Alaska. This article is part of the August-September 2020 issue of the Sound Waves newsletter. 2017; Dufresne et al. In the cave lives the evil spirit qa-htu-‘a, similar in appearance to a great toad or frog. 4 According to the legends, qa-htu-‘a still there, ready to send another deadly tsunami at any time. Researchers have also completed other surveys of the landslide areas. The boat was carried by the wave above the trees and luckily washed back into the bay, both Howard Ulrich and his son survived. Zwei dieser Stürze werden von Arbeitsgruppen untersucht, mit denen Dr. Anja Dufresne vom Institut für Ingenieurgeologie zusammenarbeitet. Geographic Names Information System (GNIS), Mapping, Remote Sensing, and Geospatial Data, August-September 2020 issue of the Sound Waves newsletter, USGS scientists recommended more fieldwork, Interferometric synthetic aperture radar data from 2020 for landslides at Barry Arm Fjord, Alaska, Potential Landslide Paths and Implications for Tsunami Hazards in Glacier Bay, Alaska – An Initial Investigation, Mountain Permafrost, Climate Change, and Rock Avalanches in Glacier Bay National Park, Alaska. There is evidence that they are increasing in size and travel distance. 2018; Higman et al. On July 9, 1958, an earthquake with an estimated magnitude of 7.7-8.3 triggered an enormous rockfall in a remote bay along the Gulf of Alaska. Aerial view of Barry Arm Fjord and glacier on June 26, 2020, showing outlines of potential landslide areas. Howard Ulrich, a fisherman visiting Lituya Bay with his 8-years-old son that day, at first heard a loud rumbling noise from up at the head of the bay, followed a moment later by what he describes as "an atomic explosion." Smaller tsunami, with a maximal wave height of 20 feet, were recorded in the Yakutat Bay, Disenchantment Bay, Dry Bay, Glacier Bay, Inian Island, Skagway and Dixon Harbor. In recent years, there has been a spate of large landslides in GBNPP that corresponded to record-breaking warm temperatures in Alaska. Bis zu einer Höhe von 520 Metern wurden die … Lituya Bay is an ice-scoured tidal inlet with a maximum depth of 722 feet (220 m). Dramatic footage shows a huge chunk of glacier dropping into the sea and triggering a wave in Alaska. It originated above land, but most of the deposit is underwater in Glacier Bay. Although landslide-generated tsunamis are historically uncommon in GBNPP, there have been plenty of landslides in and near the park, and some of them have produced tsunamis. If someone dares to disturb its sleep, it will violently shake the land and the sea. Photo credit: Gabe Wolken. Mega-tsunami hundreds of metres tall feared if Alaskan glacier disappears ... creating a tsunami wave potentially hundreds of metres high. An interesting find emerged during the study—Bathymetry data used during the research revealed a previously hidden landslide at the junction of Johns Hopkins and Tarr inlets that appears to have occurred sometime after 1892 when glaciers withdrew from the area. 2018). Opinions expressed by Forbes Contributors are their own. Diese enorme Menge hatte einen Megatsunami zur Folge. Juli dieses Jahres kam es um 22 Ortszeit an der Fairweather-Bruchline (58.340 N; 136.520 W), die sich nordwestlich der Bucht befindet, zu einem Erdbeben der Stärke 8,3 auf der Richterskala, dessen Epizentrum knapp dreizehn Meilen von Lityua Bay entfernt lag. AN UNPRECEDENTED 'mega-tsunami' could be caused by a melting Alaska glacier, scientists have warned.
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