Steven Dutch, Professor Emeritus, Natural and Applied Sciences, Universityof Wisconsin - Green Bay
|I may have purchased the last available copy of this classic paper, but since the references I have to it elicit a fair amount of interest, I have scanned it as a service to the geological community. |
To the best of my knowledge, this is all public domain. This has been edited into Web format and figures inserted where most appropriate. The table of contents and index are omitted since they refer to page numbers in the original text. A few typos in the original have been corrected.
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Lituya Bay, on the northeast shore of the Gulf of Alaska, is an ice-scoured tidal inlet with a maximum depth of 720 feet and a sill depth, at the narrow entrance, of only 33 feet. The northeastward-trending stem of the T-shaped bay, 7 miles long and as much as 2 miles wide, transects the narrow coastal lowland and foothills belt flanking the Fairweather Range of the St. Elias Mountains. The two arms at the head of the bay, Gilbert and Crillon Inlets, are part of a great trench along the Fairweather fault. Gentle slopes border the outer part of the bay, but the walls of the inner, fiordlike part rise steeply to altitudes of 2,200 feet to more than 6,000 feet.Until recently, little notice was taken of the giant waves that have rushed out from the head of Lituya Bay, leaving sharp trimlines to mark the upper limit of total or near total destruction of the forest along the shores. The dates of occurrence of 4 known and 1 inferred giant waves, and the maximum altitudes of their trimlines are as follows: July 9, 1958-1,720 feet ; October 27, 1936-490 feet ; 1899 (?)-about 200 feet ; about 1874-80 feet ; and 1853 or 1854-395 feet.In 1958 about 40 million cubic yards of rock, loosened either by displacement on the Fairweather fault or by the accompanying shaking, plunged into Gilbert Inlet from a maximum altitude of about 3,000 feet on the steep northeast wall. This rockslide caused water to surge over the opposite wall of the inlet to a maximum altitude of 1,740 feet, and generated a gravity wave that moved out the bay to the mouth at a speed probably between 97 and 130 miles per hour. Two of three fishing boats in the outer part of the bay were sunk, and two persons were killed. The interpretation that water was primarily responsible for destruction of the forest over a total area of 4 square miles, extending to a maximum altitude of 1,720 feet and as much as 3,600 feet in from the high-tide shoreline, is supported by eyewitness accounts of the survivors, by the writer's field investigation, and by R. L. Wiegel's study of a model of Lituya Bay and his calculations from existing theory and data on wave hydraulics.The giant waves in 1936 were generated in Crillon Inlet. They were described by eyewitnesses at a point about midway along the bay as 3 waves of increasing height, in close succession and traveling about 22 miles per hour. Of the possible causes considered here, movement of a tidal glacier front or submarine sliding seems most likely but can be neither disproved nor conclusively supported from the information at hand.The configuration of trimlines formed by giant waves in late 1853 or early 1854 (dated by tree ring count) and about 1874, suggests sliding from the south wall of Lituya Bay at Mudslide Creek as a likely cause. A slide, fault displacement, or some other disturbance in Crillon Inlet may have caused anothergiant wave during one of the great earthquakes in September 1899.The frequent occurrence of giant waves in Lituya Bay, as compared to other similar bays, is attributed to the combined effect of recently glaciated steep slopes, highly fractured rocksand deep water in an active fault zone, heavy rainfall, and frequent freezing and thawing. These waves are likely to occur again, and should be taken into account in any future use ofLituya Bay. Other giant waves have been caused by sliding of part of a mountain into Shimabara Bay in Japan ; repeatedly by falling or sliding of rock masses into Loen Lake, Tafjord, and Langfjord in Norway; by avalanching of a hanging glacier intoDisenchantment Bay in Alaska; and repeatedly by landslides into Franklin D. Roosevelt Lake in Washington.
Lituya Bay is an ice-scoured, nearly landlocked tidal inlet on the northeast shore of the Gulf of Alaska (fig. 14). Most descriptions of Lituya Bay, including that of its discoverer La Perouse (1798), have dwelt at length on the hazards of the strong tidal current in the narrow entrance, but until recently, little notice was taken of an even more remarkable and potentially more dangerous hydraulic oddity of the bay-its propensity for developing enormous waves. At least four times during a little more than a century giant waves have rushed out from the head of the bay, destroying the forest on the shores and leaving trimlines similar to those formed by glaciers. The latest and largest of these waves washed out trees to a maximum altitude of 1,720 feet, more than 8 times the maximum recorded height of a tsunami breaking on an ocean shore (Leet, 1948, p.179).
Figure 14. Map of part of southeastern Alaska, showing location and regional geographic setting of Lituya Bay.
The writer became interested in the giant waves while studying the Tertiary rocks in Lituya Bay and adjoining area in 1952 and 1953, as a part of the U.S. Geological Survey's program of petroleum investigations in the Gulf of Alaska region. The two trimlines then recognized were mapped and their approximate ages determined, inquiries were made of residents and former residents of the region, and a search was begun for references to the origin of the trimlines in Lituya Bay and to comparable features in other places. In apaper read at geological meetings in Seattle, Wash. and Anchorage, Alaska, and published in abstract (Miller, 1954) the trimlines in Lituya Bay were attributed to cataclysmic floods or waves of water moving out from the head of the bay at high velocity. The information then available did not give conclusive supportto any of several possible mechanisms that were suggested for setting the water in motion.
The investigation of the cause of the floods or waves was laid aside, except for correspondence and the accumulation of additional references, until the spring of 1958 when assignment to a field mapping project basedin Juneau afforded opportunities to resume the searchfor local sources of information. On July 9 muchnew information was provided in a dramatic and wholly unexpected way when a major earthquake centering near Lituya Bay was followed almost immediately by a wave that denuded an area of about 4 square miles in Lituya Bay, destroyed 2 of 3 fishing boats anchored in the bay, and killed 2 people. The problem of the cause of the waves, until then mainly of scientific interest, became overnight a matter of general public interest.
The earthquake late in the evening of July 9 (Morning of July 10, Greenwich civil time; Pacific standard time (120 W. meridian time) is used throughout this report.) was strongly felt on the U.S. Geological Survey power barge, Stephen R. Capp8, at anchor in Glacier Bay about 60 miles east of Lituya Bay. Rocks fell into the water from steep cliffs nearby, causing small waves that broke with a height of not more than 2 or 3 feet on the shores; no large waves were seen, however. Upon learning by radio on the following morning of the destruction in Lituya Bay, the writer chartered a small pontoon-equipped airplane, and spent about 1-1/2 hours flying over the bay at low altitude. Observation and photography were hampered by low ceiling, rain, and fog, and no landings could be made in the debris choked bay. Early in August, when the power barge was anchored in Dixon Harbor about 30 miles southeast of Lituya Bay, a helicopter was used for 1-1/2 days of ground and aerial observations and photography of the bay. In late August and early September the writer again photographed and examined Lituya Bay on several flights with fixed-wing aircraft, and camped for 3 days in the bay.
On August 29, 1958, a photographic mission of the U.S. Coast and Geodetic Survey photographed the entire Lituya Bay area with a 9-lens aerial camera, and also made single-lens vertical photographs of the entrance.
D. L. Rossman, George Plafker, R. C. Ellis, E. A. Hainze, and Todd Nelson all assisted in the field at times during the 1952-53 seasons. R. L. Velikanje, C. L. Sainsbury, R. E. Marsh, Mrs. Caroline Jensen, and L. H. Bayers in the Juneau office of the U.S. Geological Survey canvassed potential sources of information by interview and letter. R. F. Taylor, forester in charge of the Alaska Forest Research Center in Juneau, gave advice on tree ring studies made in the field in 1953 and arranged for preparation of tree sections; R. M.Godman of the same organization counted and interpreted the growth rings.
A. J. Mitchell, superintendent of the Sitka andGlacier Bay National Monuments, in 1958 aided ingathering local information on the waves, provided logistic support and encouragement to the investigation, and accompanied the writer on one flight to Lituya Bay. J. P. McKee, E. L. Henrickson, V. I. Mann and Edward Berdusco of the Fremont Mining Co. provided a valuable record of conditions in Lituya Bay immediately preceding the 1958 wave and also called attention to evidence for movement along the Fairweather fault near Lituya Bay. Part of the logistic support for the 1958 field investigation was provided by the Geological Survey's southeastern Alaska project barge and helicopter and by Seventeenth Coast Guard District airplane. Special thanks are due to pilot Kenneth Loken of Juneau for making it possible to inspect Lituya Bay shortly after the 1958 wave, despite adverse weather.
Don Tocher of the University of California Seismographic Station joined the writer in making a field investigation of the effects of the 1958 earthquake, and contributed valuable suggestions on the interpretation of the giant waves and on the preparation of this report. R. L. Wiegel of the Institute of Engineering Research, University of California, made a model study of the 1958 wave and generously contributed the resulting observations for quotation in this report. A. R. Tagg of the U.S. Geological Survey made the photogrammetric measurements of trimline altitudes. The writer is indebted to F. H. Fredrickson, Mr. and Mrs. W. A. Swanson, and H. G. Ulrich for their cooperation in providing eyewitness accounts of the waves. Photographs of Lituya Bay and information on the waves were furnished by W. O. Field, Jr., of the American Geographical Society, Bradford Washburn, of the Museum of Science, Boston, Mass., and Tom Smith, Trevor Davis and Robert De Armond of Juneau. Finally, many other persons not specifically mentioned here have contributed suggestions as to the cause of the waves, sources of information and methods of attacking the problem, and helpful criticism of the manuscript.
Lituya Bay is a T-shaped inlet that cuts through the coastal lowland and foothills belt flanking the Fairweather Range of the St. Elias Mountains, on the south coast of Alaska (fig. 14, pl. 2).
The entrance of the bay, at lat 58�36'45" N., long 137�39'40" W., is 122 miles west of Juneau and 99 miles southeast of Yakutat. The main part of the bay, corresponding to the stem of the letter T, is 7 miles long and ranges from three-fourths of a mile to 2 miles in width except at the entrance, which has a width of only 1,000 feet at low tide. Cenotaph Island divides the central part of the bay into two channels, two-fifths and four-fifths of a mile in width. Gilbert and Crillon Inlets extend northwestward and southeastward, respectively, from the head of the bay to form, the upper part of the T, which in 1958 was about 3 miles long. The name "Lituya," according to Emmons (1911, p. 294), is a compound word in the Tlingit language meaning "the lake within the point," in reference to the nearly landlocked nature of the bay.
Lituya Bay was aptly described by Dall (1883, p. 204) as "a Yosemite Valley, retaining its glaciers and with its floor submerged six or eight hundred feet." The bay fills and slightly overflows a depression only recently occupied by a piedmont glacier lobe and its tributary valley glaciers, of which the present Lituya, Cascade, and North Crillon Glaciers are remnants (pl. 2). The maximum stand of the Lituya Glacier system is clearly recorded by the arcuate end moraine that forms La Chaussee Spit and is continuous with lateral moraines and trimlines rising gradually to an average altitude of about 1,800 feet at the head of the bay (pl. 3 A.). The Solomon Railroad (pl. 2), a part of the end and lateral moraine north of the bay, rises abruptly like a railroad embankment to a sharp, even crest standing as much as 600 feet above the adjoining lowlands.
Lituya and North Crillon Glaciers, each about 12 miles long and 1 mile wide, originate in ice fields at altitudes of 4,000 feet and higher near the crest of the Fairweather Range. Both glaciers flow southwestward down the flank of the Fairweather Range and make nearly right-angle turns into the northwestward-trending trench between this range and the foothills. In the summer of 1958 about 1,600 feet or one-third of the total width of the front of North Crillon Glacier was tidal at the head of Crillon Inlet. The surface of this glacier near the front was mostly debris covered and relatively smooth. Just prior to the earthquake and wave in 1958 about 3,000 feet of the front of Lituya Glacier was tidal. The surface of this glacier near the front was rough, with little debris cover except along the southwest margin and at a narrow medial moraine near the northeast margin. At the end of August 1958 almost the entire front of Lituya Glacier was tidal, and deeply crevassed. Cascade Glacier is about 4 miles long and very steep. Its terminus in recent years has been low and largely debris covered. At the end of August 1958 only a small part of the glacier terminus reached the high-tide shoreline at the head of Lituya Bay.
The shores around the outer part of Lituya Bay are mainly bouldery beaches, the adjoining land risingaway from the beach at rates ranging from 100 feet in a horizontal distance of 6,000 feet, near Fish Lake, to 540 feet in a horizontal distance of 1,200 feet at The Paps (pl. 2). Around the head of the bay the walls are steep and fiordlike, rising to altitudes between 2,200 and 3,400 feet in the foothills immediately to the north and south, and to more than 6,000 feet in the Fairweather Range less than 2 miles from the shore of Crillon Inlet. The submarine contours, based on soundings made in 1926 and 1940 (U.S. Coast and Geodetic Survey, 1942), show a pronounced U-shaped trench with steep walls and a broad, flat floor sloping gently downward from the head of the bay to a maximum depth of 720 feet just south of Cenotaph Island, and rising again toward the outer part of the bay. The minimum depth in the entrance is 33 feet at mean lower low water; hence the bay has a closure of at least 687 feet. The tide in the bay is diurnal, with a mean range of 7 feet and a maximum range of about 15 feet (U.S. Coast and Geodetic Survey, 1957). The tidal current in the narrow entrance attains a velocity of 12 knots (U.S. Coast and Geodetic Survey, 1952), or about 13.8 statute miles per hour.
Weather records for the 2 stations nearest Lituya Bay, at Cape Spencer 47 miles to the southeast and at Yakutat 99 miles to the northwest (U.S. Weather Bureau, 1958), indicate that the total annual precipitation ranges from 111 to 134 inches and the mean annual temperature ranges from 39� to 41� F. in this coastal area. Because of the heavy precipitation and mild climate at low altitude, the lower slopes (from the high tide line to an altitude of 1,700 to 2,000 feet) where not overly steep or poorly drained, normally are covered by a dense growth of trees and brush. Reforestation of land newly exposed by the retreat of glaciers or the sea, or, as in Lituya Bay, denuded by waves, under present climatic conditions at this latitude takes place in the following succession : dense stands of alder(Almus) and willow (Salix) grow within a few years, but are soon exceeded in height by cottonwood (Populus trichocarpa) ; Sitka spruce (Picea sitchensis) nextdominates but gradually becomes mixed with hemlock (Tsuga he:terophylla and T. mertensiana) ; and finally Alaska cedar (Chamaecyparis nootkatensis) appears. At the time of the 1958 wave, forests of five distinct ages were growing on or near the shores of Lituya Bay. These zones, as identified on plate 8A, are: mixed alder, willow, cottonwood, and spruce with a known maximum age of 22 years (shore to h) ; 2 bands of mixed spruce and cottonwood with maximum ages of about 84 years (h-j) and of 105 years (j-k); mixed spruce and hemlock with an estimated age of 400 years or more (k-m); and mixed spruce, hemlock, and cedar probably more than 1,000 years old (above m).
Lituya Bay lies near the southeast end of and transects a geologic province in which sedimentary rocksof Tertiary age are exposed or inferred to underlie lowland areas (Gryc, Miller, and Payne, 1951, p. 159-162).The two arms at the head of Lituya Bay are part of agreat trench that extends for many miles to the northwest and southeast along the southwest front of theFairweather Range and the southern part of the St.Elias Mountains (fig. 14). Mertie (1931, p. 123) first recognized this trench as the topographic expressionof a major fault, named more recently the Fairweatherfault (Miller, 1953). Field investigations by the writer and by D. L. Rossman (written communication, 1957) indicate that the Fairweather fault from the vicinity of Lituya Bay southeast to Palma Bay is vertical or dips steeply to the northeast. Along this fault the crystalline rocks exposed on the northeast side are inferred to have moved up relative to less altered and in part younger rocks exposed in the lowland and foothills belt on the southwest side. St. Amand (1957, p. 1357-1359) suggested, however, that the fault is of lateral or oblique habit, and cited as evidence some of the effects of the 1899 earthquakes in Yakutat Bay.
Instrumental and field observations point to movement along the Fairweather fault as the cause of the earthquake immediately preceding the 1958 wave in Lituya Bay. Tocher and Miller (1959) studied the surface breakage where the trace of the fault is exposed near Crillon Lake, 6 to 10 miles southeast of Lituya Bay. At one point the southwest side moved northwestward at least 21-1/2 feet and up 3-1/2 feet. Slides and other evidence of strong shaking observed elsewhere along known or inferred trace of the Fairweather fault from Palma Bay to the latitude of Nunatak Fiord near Yakutat Bay, indicated tearing along the fault probably for 115 miles or more. The instrumental epicenter of the earthquake, as determined by the U.S. Coast and Geodetic Survey (Brazes and Jordan, 1958, p. 36), is lat 58.6�N., long 137.1�W., a point in the Fairweather Range about 71/2 miles east of the surface trace of the Fairweather fault and 13 miles southeast of the head of Lituya Bay. A later determination from a larger number of stations (William Stauder, written communication, paper given at Tucson meeting of Geol. Soc. America; oral communication, Apr. 29, 1959) places the epicenter farther southeast but nearer the assumed surface trace of the Fairweather fault.
Bedrock is exposed or lies beneath only a thin veneer of soil, glacial drift, or talus at water level around mostof Cenotaph Island and from a point 4-1/2 miles inside the entrance on the south shore around the head of Lituya Bay to a point 5-1/2 miles inside the entrance on the north shore. The rocks are largely hard schist on the northeast shore of Gilbert and Crillon Inlets. Diorite and slightly metamorphosed volcanic rocks, slate, and graywacke are exposed on the southwest shore of Gilbert Inlet and the adjoining north shore of the bay, on the southwest shore of Crillon Inlet, and on the south shore of the bay as far as the mouth of Coal Creek. Bedded sedimentary and volcanic rocks of Tertiary age are exposed on Cenotaph Island and on the south shore west of Coal Creek. Around most of the outer part of the bay boulder till is exposed at the surface or lies under a thin soil.
Field observations in 1952 and 1953 indicated that the forest inside the moraine enclosing the outer part of Lituya Bay, but above the highest trimline, is distinctly younger than the forest growing along the coast outside of the moraine. Although no tree ring counts were made, the writer noticed that there was much less deadfall in the forest inside the moraine, and that the spruce and hemlock trees were smaller inside the moraine. Moreover, Alaska cedar trees as much as 3 feet in diameter were found growing up to the outer edge of the moraine, but not even small cedars were seen inside the moraine. This evidence of a post-Wisconsin advance of ice to the mouth of Lituya Bay is now corroborated by evidence newly exposed by the 1958 giant wave. An ice-sheared stump, rooted in a humus-rich soil just below the surficial till on the south shore near the entrance of the bay (fig. 15, loc. A), has a radiocarbon age of 6,060+/-200 years B. P. (Meyer Rubin, written communication, U.S. Geological Survey lab. no W-800 report, May 26,1959).
The evidence indicates that ice stood at or near the mouth of Lituya Bay within the time required for growth of a climax forest in this region, possibly less than 1,000 years ago. However, the ice fronts were farther back when the La Perouse expedition visited Lituya Bay in 1786 than at the present time. The map made under the direction of La Perouse (1798, opposite p. 146; also Klotz, 1899) shows two tidal glaciers at the head of each inlet, which indicates that the ice fronts had retreated to positions beyond the points where the Lituya and North Crillon Glaciers enter the trench at the head of the bay. The combined length of Gilbert and Crillon Inlets then was about 9 miles. By 1894 both Lituya and North Crillon Glaciers had readvanced nearly to their present positions (Klotz, 1899). Prior to the 1958 wave low deltas of gravel had built out into Gilbert Inlet at the southwest and northeast margins of the Lituya Glacier front, and into Crillon Inletacross about two-thirds of the width of the North Crillon Glacier front (fig. 15). These deltas formed after 1894, and they may be, or may have been, in part underlain by ice projecting from the glacier fronts below sea level.
Available records of the exploration and settlement of the northeastern Gulf of Alaska coast afford only a sketchy history of Lituya Bay beginning in 1786. Little information has been found for the period 1788-1874, during which time at least one destructive wave occurred and Indian settlements in the bay were abandoned, perhaps as a direct result of a wave. Records of visits to or settlement in the bay after 1874, including the accounts of geographic surveys and scientific investigations, contain few references to the occurrence of large waves.
The French explorer La Perouse (1798, p. 115-169) is generally credited with the discovery of Lituya Bay, which he named Port des Francois. In the course of a projected trip around the world La Perouse took his ships La Boussole and L'Astrolabe into Lituya Bay on July 2, 1786. During a stay of nearly a month the expedition mapped Lituya Bay on a scale of 1: 50,000, traded with the Indians then living in and near the bay, and recorded observations on the native culture and the plant and animal life in the vicinity. Twenty-one men were drowned when three small boats engaged in a survey of the entrance were swept into the tidal bore and two were wrecked. In July 1788 Ismailof and Becharof entered Lituya Bay on the ship Three Saints to claim the land for Russia and to induce the natives to accept Russian rule (Shelikof, 1812, p. 108-112). The lack of any reference to waves within the bay in either of these early accounts, together with the mention of trees and native dwellings near the shore, are indirect evidence that no giant waves had occurred in Lituya Bay for some time prior to 1788.
For the remainder of the period of Russian rule andthe early years of American rule, until 1874, the literature examined contains only brief mention of exploration in Lituya Bay: in connection with an expedition of the Russian ship Orel to obtain sea otter skins in 1796 (Bancroft, 1886, p. 356-357); the reported discovery and mining of gold placer deposits on thebeaches in the vicinity of Lituya Bay by American whaling ships (Dall, 1883, p. 202). Russian censuses of the Tlingit tribe give the population of the Lituya clan or settlement as 200 in 1835, and 590 in 1861 (Petroff, 1884, p. 96, 99). Perhaps only asmall part of the clan lived in Lituya Bay, for the French and Russian expeditions in 1786 and 1788 reported that the main village was northwest of the bay.
A U.S. Coast and Geodetic Survey party entered Lituya Bay in 1874 to make geodetic observations and to revise the La Perouse chart of the outer part of the bay (Dall, 1878, p. 158; 1833). No natives were then living in the bay and the village on the south shore seemed to have been abandoned for a long time. In 1894 a topographic map of the region adjoining Lituya Bay was made by a Canadian party of the International Boundary Survey (U.S. Congress, 1904; International Boundary Commission, 1952, p. 254) ; observations on the glaciers at the head of the bay were later published by Klotz (1899, p. 524-526, maps). The bay was visited by field parties of the U.S. Geological Survey for 3 days in 1906 (Wright, F. E., and Wright, C. W. in Reid, 1908, p. 53; in Buddington and Chapin, 1929, p. 269-270) and in 1917 (Mertie, 1931), and for 5 days in 1943 (Kennedy and Walton, 1946, p. 67-72). Surveys of the bay were resumed by the U.S. Coast and Geodetic Survey in 1926 and 1940, resulting in the current navigation chart on a scale of 1: 20,000 (U.S. Coast and Geodetic Survey, 1942). In 1926, and during part of each summer from 1930 to 1934, expeditions engaged in mountain climbing or geographical and geological exploration were based in or near Lituya Bay (Carpe, 1931; Washburn, 1935, 1936; Goldthwait, 1936). Except for the brief mention of "evidence of flooding or washing to a height of at least 10 feet," which Dall (1883, p. 203) attributed to damming of the entrance by ice during the winter, none of the reports on the expeditions just described contain any reference to the giant waves in Lituya Bay.
Placer mining of the gold in the sands along the ocean beach adjacent to the mouth of Lituya Bay was begun by the Americans in 1890 (Boursin, 1893, p. 230) and continued intermittently at least until 1917 (Mertie, 1931, p. 133). Since Lituya Bay served as a port for this operation, during this period it was probably occupied or at least visited frequently. One man, James Huscroft, lived on Cenotaph Island in Lituya Bay almost continuously from 1917 to about 1940. Huscroft and another man were on the island, and two men were in a boat nearby, at the time of the 1936 waves. Their eyewitness accounts, the observations of Tom Smith and others who visited the bay only a few days later, and the observations of J. P. Williams nearly a year later, led to the earliest known published references to the unusual "waves or floods" of water in Lituya Bay (Alaska Daily Press, 1936; Williams, 1938).
Lituya Bay was incorporated in the Glacier Bay National Monument when the boundary was extended in 1939 to include the coastal area from Cape Spencer north to Cape Fairweather (fig. 14). No one has lived permanently either in or near the bay since Huscroft died, but in recent years the bay has come into increasing use as an overnight anchorage and refuge in bad weather for the trolling boats of the fishermen who ply the adjoining waters of the Gulf of Alaska during the summer and early fall.
Created 8 January 1998, Last Update 29 December 1999