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. This mass of rock plunged from an altitude of approximately 3000 feet (914 meters) down into the waters of Gilbert Inlet (see map below). The impact force of the rockfall generated a local tsunami that crashed against the southwest shoreline of Gilbert Inlet.
The wave hit with such power that it swept completely over the spur of land that separates Gilbert Inlet from the main body of Lituya Bay. The wave then continued down the entire length of Lituya Bay, over La Chaussee Spit and into the Gulf of Alaska. The force of the wave removed all trees and vegetation from elevations as high as 1720 feet (524 meters) above sea level. Millions of trees were uprooted and swept away by the wave. This is the highest runup ever recorded for a tsunami.
Alaskan Rocks Feet
In brief, weathering crumbles rocks and minerals apart into smaller pieces. Erosion carries these pieces away by water, wind, glaciers, and gravity, often transporting the pieces for long distances. In Denali, ice is the predominant mechanism of erosion.
In the high, frozen regions of the Alaska Range, snow and ice are the main forms of precipitation. In the past, most of the snow and ice remained behind; very little melting occurred. Snow and ice accumulated and got deeper and deeper, year after year, until the mass of ice that formed was so thick it compressed under its own weight. Gravity caused this ice to flow through stream valleys as glaciers. Glaciers are rivers of ice. The glaciers we see today in the park are increasingly small remnants of their former selves, but all around us we can see evidence of how they dominated the landscape. During past ice ages, most recently about 10,000 years ago, glaciers covered the Alaska Range and much of Alaska in ice. All of south-central Alaska has been buried in ice numerous times, and the shape of the land in this area comes from the carving forces of glaciers and the debris they leave behind.Glaciers are often fed by more snow and ice precipitating and accumulating at higher elevations. If ice builds up at its source, a glacier may flow at rates ranging from several feet per year to several feet per day. As a glacier flows downhill, it grinds away at its beds with tremendous force. It picks up rocks from its bed, grinding some to a fine powder called silt and by plucking up larger chunks. When the glacial ice melts, the silt is carried along in the meltwater to be deposited downstream as outwash. Streams flowing from melting glaciers are often milky-colored. The silt in the water is called glacial flour, and the silty water is described as glacial milk. The larger chunks get left behind as erratics or in unsorted deposits forming ridges or hills called moraines.
Erratics are rocks that are foreign to the surrounding terrain. They differ from the types of rock found where they are deposited.The rocks embedded in glacial ice grind away at bedrock, forming the jagged ridges and deep U-shaped valleys found in the range. Large blocks of ice can be stranded in the moraines left behind by retreating glaciers. When they finally melt, a water-filled depression known as a kettle lake develops. The carving action of ice forms many of the elongated lakes in the upper Susitna Valley to the south of Denali, and examination of a map reveals that they are all oriented in the direction that the ice was moving.
11,300 feet up Mount St. Elias, another group of climbers felt the ground moving in waves as avalanches pounded down the slopes around them. Nine days later, descending after a blizzard suffocated one of the men in his tent, the survivors found the landscape of snow and ice deeply altered, and no sign of the lower camp where they had cached their snowshoes.
The Fairweather fault runs directly through Gilbert and Crillon inlets, which form the crosspiece at the top of Lituya Bay's distinctive "T" shape. During the earthquake, the southwest side of the inlets moved about 20 feet northwest relative to the opposite shore, on the other side of the fault.
Don Miller, the geologist, was on a USGS barge in Glacier Bay when the earthquake struck. The barge heaved, and Miller watched as rocks fell from high cliffs into the bay. In the morning, he learned of the disaster in Lituya Bay and chartered a float plane to take him there. They flew over rafts of logs fanning out in the open water as far as five miles from the mouth of the bay. Once over the bay, they could not land because its entire surface was strewn with tree trunks and giant blocks of ice.
When Miller returned to study the effects of the wave, he measured the highest trimline more precisely at 1,720 feet. For most of the bay, destruction below the trimline was absolute. Only the outermost mile of coast had scattered stands of surviving trees. The lighthouse at Harbor Point and the cabin on Cenotaph Island were both gone without a trace. The site of the mountaineers' camp was scoured down to bedrock.
To Miller, the destruction he saw was clearly the work of a giant wave, but its height seemed unbelievable. Miller wrote that his observations were "widely doubted both on theoretical grounds and on the basis of aerial observations and study of photographs by others." Scientists who had not seen the effects of the wave firsthand argued that above 300 feet, the soil and trees must have slid into the bay during the earthquake. But Miller had seen driftwood and rocks strewn across the slopes at the top of the trimline, and the trees that had not been washed into the bay all lay on the ground pointing westward, as the wave had traveled. Miller could not explain how the earthquake had caused such an enormous wave, but he was certain that it had.
A second Berkeley researcher, R.L. Wiegel, built a 1:1000 scale model of Lituya Bay and found that he could more or less recreate Miller's observations given a large enough mass of rocks falling as a unit into Gilbert Inlet at high velocity. The landslide scar, which was high above Gilbert Inlet on a near-vertical slope, appeared to have dumped about 40 million tons of rock into the inlet all at once.
In 2001, Hermann Fritz and Willi Hager attempted to replicate the initial wave's 1,720-foot run-up using a pneumatic landslide generator to blast simulated rockslides into at 1:675 scale model of Gilbert Inlet. Fritz and Hager found that a slide like the one at Gilbert Inlet could generate that much run-up because the rapid impact of the slide would bring a large air cavity into the water behind it, displacing far more water than just the volume of the rock.
Wiegel's and Fritz's research reinforced Miller's observations as well as Ulrich's eyewitness account of the massive wave in Gilbert Inlet. However, Steven Ward and Simon Day of UC Santa Cruz felt that the Gilbert Inlet slide alone could not account for the size of the wave that swept through the outer bay or the amount of material deposited at the bottom of Gilbert Inlet. Their 2010 paper describes a possible double slide, where the destruction of the toe of Lituya Glacier triggered a much larger, slower submarine slide of glacial deposits after the initial rockslide. Proving this would require surveying the bottom of Gilbert Inlet to measure and date the layers of sediment. In other words, 60 years after the Lituya Bay tsunami, we are still working out how it happened.
During the earthquake, the bay side of Gilbert and Crillon inlets moved about 20 feet northwest relative to the northeast wall that forms the head of the bay. The Sunmore (S) and Badger (B) were anchored in Anchorage Cove, while the Edrie (E) was anchored in the small cove behind the Paps hills. (Map from Miller, Great Waves in Lituya Bay, Alaska)
The spur that forms the corner between Gilbert Inlet and the main body of Lituya Bay. This is the site of the 1,720-foot run-up, the highest ever documented. One World Trade Center in New York City is only 56 feet taller. (Photo: USGS)
I sat on the edge of the Zodiac as we zoomed down the fjord. Chunks of ice floated around us, ranging in size from cubes that could fit in a glass to icebergs as big as my apartment. I pulled my warmest clothes closer to my body as the cold glacial winds made me shiver. The Tracy Arm Fjord, south of Juneau, Alaska, is a cathedral of stone and ice. Giant rock faces stretch thousands of feet into the sky as icebergs reach deep below the water and into the murky depths.
My time in Alaska taught me that rocks are our eldest knowledge holders. Understanding ice, glaciers, mountains, and rocks is like understanding the language of the Earth. After this trip, I believe that when we understand and connect personally with the Earth, we are more deeply inspired to protect it.
The slope threatening the port has rocks placed over 600 feet above the dock, and the area was subject to rockslides earlier, with local leaders pointing out two slides that took place fall of 2017. Juneau, an Alaska-based KTOO, highlights another slide in June. However, everyone was lucky, and no one was injured.
12. Otters might look soft and cuddly but remain dangerous wild animals. Otters have strong teeth and a powerful bite. So, whether you see an otter on land or at sea, be sure to maintain a safe distance of at least 5 kayak lengths or 60 feet from the otters. Learn more about staying safe around sea otters.
Garvey had completed a morning climb Friday with partner Matt Howard and was leading a second climb at noon when Howard noticed the safety rope go slack. Howard turned and saw Garvey hit the rock outcrop on which he was standing and roll a few feet down a shale slope. Garvey died when his rope was cut during a short leader fall. He fell over 100 feet to the ground.
The rocks on the route were on the side of a glacier carved valley, and were known for being sharp. Another employee of ours had climbed with Garvey in this area and remembers doing a route several years ago that incorporated an otherwise easy layback section that was unclimbable because the sharp rock edges sliced his fingers open. (Source: Bill Laxson, Alaska Mountain Rescue Group) 2ff7e9595c
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