Tsunami Event

Date Tsunami Cause Tsunami Source Location Tsunami Parameters
Max
Water
Height		 Num. of
Runups		 Deposits Magnitude Tsu
Int		 Warn Status
Year Mo Dy Hr Mn Sec Val Code Country Name Latitude Longitude Abe Iida
1946 4 1 12 28 56.0 4 1 USA UNIMAK ISLAND, AK 53.320 -163.190 35.05 511 7 5.10 4.00
tsevent
Tsunami Effects Total Effects (Tsunami and Source)
Deaths Missing Injuries Damage Houses Destroyed Houses Damaged Deaths Missing Injuries Damage Houses Destroyed Houses Damaged
Num De Num De Num De $Mill De Num De Num De Num De Num De Num De $Mill De Num De Num De
164 3 26.26 4 3 164 3 26.26 4 3
Tsunami Comments

Comments for the Tsunami Event

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On April 1, 1946, at 12:29 [local time] a rather strong magnitude 7.4 earthquake occurred with source to the south of Unimak Island, causing one of the most destructive tsunamis in the Pacific Ocean. (reference #414)

The earthquake, with a rupture which occupied a 100 mile by 50 mile block between southeast of Scotch Cap and southeast of Sanak Islands, produced a Pacific-wide tsunami disproportionate to its zone of rupture. 30-40 seconds of shaking were reported at the U.S. Coast Guard Direction Finding station on Unimak Island, but the extensive property damage and loss of life associated with this event were a result of the associated tsunami. Houses and structures throughout the area were destroyed, including the Pankof and Scotch Cap lighthouses; the latter resulted in five deaths and an antenna at 33m height was washed away. Hawaii experienced the worst damage, with 158 deaths (96 at Hilo) and $26 million in property loss. Total property damage in Alaska was $250,000; while California experienced one death and $10,000 damage from the tsunami. These events led to the development of tsunami travel time charts for the Pacific and the Pacific Tsunami Warning Service.

Warnings were issued to many communities through the Coast Guard although a formal system for doing so was not yet in place. Some communities took precautions in evacuating lowlying areas. The warnings triggered another phenomena which has plagued mitigation efforts in all subsequent events. They triggered a reverse response in attracting crowds to the beach. This event happened on April 1, April Fools Day, and some mistook the warning and reports of a tsunami as a hoax. (reference #237)

Reference #150 lists Hawaiian Islands great damage, 173 deaths, Hilo: 448 structures destroyed. 78 deaths.

View a calculated tsunami-travel-time map.

References for a Tsunami event ID

References for the Tsunami Event

ID Author Year Citation
45 U.S. Department of the Interior, Geological Survey and U.S. Department of Commerce, National Oceanic and Atmospheric Administration 1928-1986 United States Earthquakes, Annual publication, published 1928-1986. vol.s for 1928-1965 issued by the U.S. Coast and Geodetic Survey; volumes for 1966-1969 issued by the National Earthquake Information Center; volume for 1970 issued by the National Geophysical Data Center; volumes for 1971-1972 issued by the National Geophysical And Solar-Terrestrial Data Center; volumes for 1973-1980 published jointly by the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Geological Survey; volumes for 1981-1986 published by the U.S. Geological Survey. [on shelf]
79 Iida, Kumizi, Doak C. Cox, and George Pararas-Carayannis 1967 Preliminary Catalog of Tsunamis Occurring in the Pacific Ocean, HIG-67-10, Hawaii Institute of Geophysics, University of Hawaii, Honolulu, Hawaii, 275 p. Bibliography to the Preliminary Catalog of Tsunamis Occurring in the Pacific Ocean, December 1967, 27 p.
88 Duda, Seweryn J. 1965 Secular seismic energy release in the circum-Pacific belt. Tectonophysics, vol. 2, no. 5, p. 409-452. DOI:10.1016/0040-1951(65)90035-1
130 Gutenberg, B. and C.F. Richter 1965 Seismicity of the earth and associated phenomena. Princeton University Press, 1954 (second edition); Hafner Publishing Company, New York and London (facsimile edition), 310 p.
150 Iida, Kumizi 1984 Catalog of tsunamis in Japan and its neighboring countries. Aichi Institute of Technology, Yachigusa, Yakusa-cho, Toyota-shi, 470-03, Japan, 52 p.
222 Johnson, Jean M., and Kenji Satake 1997 Estimation of seismic moment and slip distribution of the April 1, 1946, Aleutian tsunami earthquake. Journal of Geophysical Research, vol. 102, no. B6, p. 11765-11774. DOI:10.1029/97JB00274
236 Lander, James F., and Patricia A. Lockridge 1989 United States Tsunamis (Including United States Possessions) 1690-1988, National Oceanic and Atmospheric Administration, National Geophysical Data Center, Boulder, Colorado, USA, Publication 41-2, 265 p.
237 Lander, James F., Patricia A. Lockridge, and Michael J. Kozuch 1993 Tsunamis affecting the West Coast of the United States, 1806-1992, KGRD no. 29, National Oceanic and Atmospheric Administration, National Geophysical Data Center, Boulder, Colorado, USA, September, 242 p.
239 Lander, James F. 1996 Tsunamis Affecting Alaska 1737-1996, KGRD no. 31, National Oceanic and Atmospheric Administration, National Geophysical Data Center, Boulder, Colorado, USA, September, 155 p.
387 Shepard, F. P., G. A. Macdonald, and D. C. Cox 1950 The Tsunami of April 1, 1946, Bulletin of the Scripps Institution of Oceanography of the University of California, vol. 5, no. 6, La Jolla, California, p. 391-528.
414 Soloviev, S.L., and Ch.N. Go 1974 A catalogue of tsunamis on the western shore of the Pacific Ocean. Academy of Sciences of the USSR, Nauka Publishing House, Moscow, 439 p. [Canadian Translation of Fisheries and Aquatic Sciences no. 5077, 1984, translation available from Canada Institute for Scientific and Technical Information, National Research Council, Ottawa, Ontario, Canada K1A OS2, 447 p.]
542 Stover, Carl W., and Jerry L. Coffman 1993 Seismicity of the United States, 1568-1989 (Revised), U.S. Geological Survey Professional Paper 1527, United States Government Printing Office, Washington, D.C.
1620 O'Brien, J.T. 1946 Preliminary Report of Seismic Sea Waves from Aleutian Earthquake of April 1, 1946, Technical Report HE 116207, Wave Project, Fluid Mechanics Laboratory, University of California at Berkeley, April, 1946, 10pp.
2050 Macdonald, G.A., F. P. Shepard, D.C. Cox 1947 The Tsunami of April 1, 1946, in the Hawaiian Islands, Pacific Science, Vol. 1, No. 1, January, 1947, p. 21-37.
2081 Green, C. K. 1946 Seismic Sea Wave of April 1, 1946, as recorded on tide gauges, Transactions, American Geophysical Union, Vol. 27, No. 4, p. 490-500.
3430 Jefferson, Glen 1946 Report of Earthquake and Tidal Wave, Unimak Island, Alaska. Memo dated April 5, 1946 to the Chief, U.S. Weather Bureau, Washington, D.C. from Glen Jefferson, (Alaska) Regional Director. (3 pages.) Attachments include: (1) Chronological reports of events occurring during the earthquakes and tidal waves; (2) U.S. Coast Guard dispatches; and (3) U.S. Navy dispatches. (24 p.)
3806 Synolakis, C.E. and E.A. Okal 2005 1992-2002: Perspective on a decade of post-tsunami surveys. In Tsunamis: Case Studies and Recent Developments, Kenji Satake, ed., Advances in Natural and Technological Hazards Research, vol. 23, p. 1-29. DOI: 10.1007/1-4020-3331-1_1
3924 Powers, H.A. 1946 The tidal wave of April 1, 1946. The Volcano Letter, vol. 491, p. 1-4.
4440 Isaacs, J.D. 1946 Field Report on the Tsunami of April 1, 1946, an extensive report of the University of California Subgroup on Oceanographic Sect. of Joint Task Force one, University of California, Berkeley, College of Engineering, UCB Water Resources Archives Tech. Rep. HE-116-216, 3 May 1946; maps, photographs, observations, Hawaiian newspaper articles.
7099 Dudley, Walter C. 2010 Personal communication (email) to Paula Dunbar, Deaths in Laupahoehoe from the April 1, 1946 tsunami.