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The 1964 Good Friday Earthquake

taken from Alaska Earthquake Information Center

On March 27, 1964, at 5:36 p.m. ADT (03:36 3/28 UTC) a great earthquake of magnitude 9.2 (moment magnitude) occurred in Prince William Sound region of Alaska. The epicenter was about 10 km east of the mouth of College Fiord, approximately 90 km west of Valdez and 120 km east of Anchorage. The epicenter was located at Lat. 61.04N, Lon. 147.73W, at a depth of approximately 25 km. This earthquake is the second largest earthquake ever recorded in the world, after a M9.5 earthquake in Chile in 1960. The duration of rupture lasted approximately 4 minutes (240 seconds).

Cause

Government Hill School damage from 1964 earthquake
This photo shows evidence of the subsidence at the Government Hill School location, Anchorage.

The northwestward motion of the Pacific plate at about 5 to 7 cm per year causes the crust of southern Alaska to be compressed and warped, with some areas along the coast being depressed and other areas inland being uplifted. After periods of tens to hundreds of years, this compression is relieved by the sudden southeastward motion of portions of coastal Alaska as they move back over the subducting Pacific plate.

As a result of the 1964 quake, the Latouche Island area moved about 18 meters to the southeast. Also, the patterns of uplift and subsidence which had been slowly developing prior to the earthquake were suddenly reversed, with areas around Montague Island being uplifted 4-9 meters and areas around Portage down-dropped as much as 3 meters. The hinge line (line of no vertical change separating the uplift and subsidence zones) extended from near the epicenter in Prince William Sound to the SE coast of Kodiak Island. This vertical deformation affected and area of approximately 250,000 km2 (100,000 miles2). The end results was the movement of the Pacific plate under the North American plate by about 9 meters on average.

Four Seasons apartment building in Anchorage damaged from the 1964 earthquake
The six-story Four Seasons apartment building in Anchorage was completely destroyed. It was unoccupied at the time of the earthquake.

Aftershocks

The aftershock zone of this earthquake was about 250 km wide and extended about 800 km from Prince William Sound to the southwestern end of Kodiak Island. The mainshock and its aftershocks occurred on a fault which is part of the boundary between the Pacific and North American plates. Thousands of aftershocks were recorded in the months following the mainshock. In the first day there were 11 aftershocks with magnitudes greater than 6.0; in the next three weeks there were 9 more. Smaller aftershocks continued for more than a year.

Damage

The area where there was significant damage covered about 130,000 square kilometers. The area in which it was felt was about 1,300,000 square kilometers (all of Alaska, parts of Canada, and south to Washington). The four minute duration of shaking triggered many landslides and avalanches. Major structural damage occurred in many of the major cities in Alaska. The damage totalled 300-400 million dollars (1964 dollars).

Middleton Island uplift from the 1964 earthquake
Middleton Island has repeatedly experienced earthquake-induced uplift, with 5 terraces visible from the last 800 years. The plateau on the right side of this picture is the original beach. The vertical uplift due to the 1964 earthquake was 3.6 meters.

Losses

The number of deaths from the earthquake totalled 131; 115 in Alaska and 16 in Oregon and California. The death toll was extrememly small for a quake of this magnitude due to low population density, the time of day and the fact that it was a holiday, and the type of material used to construct many buildings (wood).

Water Waves

Much of the damage and most of the lives lost were due to the effects of water waves. These were mainly of two kinds: the tsunami of open-ocean sea wave, generated by large-scale motion of the sea floor; and the local wave, generated by underwater landslides in bays of fiords.

The 1964 Alaska tsunami was the second largest ever recorded, again following only the one caused by the 1960 Chile earthquake (4 meters at Sitka). Of the 119 deaths attributable to the effects of the ocean, about one-third were due to the open-ocean tsunami: 4 at Newport Beach, Oregon; 12 at Crescent City, California; and about 21 in Alaska. Local waves claimed at least 82 lives. Maximum height reported for these waves were 70 meters in Valdez Arm.

Seiches, a sort of sloshing of water back and forth in a small body of water like a boat harbor or swimming pool, were observed as far away as Louisiana where a number of fishing boats were sunk. Oscillations in the height of water in wells were reported from as far away as South Africa.

Seismic Waves

In addition to damage in the epicentral region immediately following the quake, long period seismic waves traveled around the earth for several weeks. Basically the whole earth vibrated (rang) like a church bell during this time. States as far away as Texas and Florida were affected with vertical motions of up to 5 to 10 cm.

Text composed by Doug Christensen, PhD, Geophysical Institute, University of Alaska Fairbanks

Map of the location of the 1964 earthquake and the aftershocks.
This map shows location of the 1964 earthquake: star - epicenter, open circles - aftershocks occurred within 1 month after the mainshock, solid black line - estimated extent of the ruptured fault from the seismic waveform inversion (Christensen and Beck, PAGEOPH, 1994). Red lines are mapped faults.
Map composed by N. Ratchkovski.

Publications

The Alaska Earthquake Professional Papers

USGS Professional Papers on the 1964 Earthquake covers USGS Professional Paper 541 USGS Professional Paper 542 USGS Professional Paper 543 USGS Professional Paper 544 USGS Professional Paper 545 USGS Professional Paper 546

The U.S. Geological Survey published the results of investigations of the Alaska earthquake of March 27, 1964, in a series of six Professional Papers.

  • Professional Paper 541 is an introduction to the story of a great earthquake—its geologic setting and effects, the field investigations, and the public and private reconstruction efforts.
  • Professional Paper 542 describes the effects of the earthquake on Alaskan communities.
  • Professional Paper 543 describes the earthquake’s regional effects.
  • Professional Paper 544 describes the effects of the earthquake on the hydrologic regimen.
  • Professional Paper 545 describes the effects of the earthquake on transportation, communications, and utilities.
  • Professional Paper 546 is a summary of what was learned from a great earthquake about the bearing of geologic and hydrologic conditions on its effects, and about the scientific investigations needed to prepare for future earthquakes.

Other Publications

Grantz, A., G. Plafker, and R. Kachadoorian. 1964. Alaska's Good Friday earthquake, March 27, 1964, a preliminary geologic evaluation. USGS Circular: 491, 35 p.

Moore, G. W. 1964. Magnetic disturbances preceding the 1964 Alaska Earthquake. Nature 203:508-509. doi: 10.1038/203508b0

Van Dorn, W. G. 1964. Source mechanism of the tsunami of March 28, 1964 in Alaska. Proceedings of the 9th Conference on Coastal Engineering, American Society of Civil Engineers 166–190.

Plafker, G. and L. R. Mayo. 1965. Tectonic deformation, subaqueous slides, and destructive waves associated with the Alaskan March 27, 1964, earthquake: an interim geologic evaluation. USGS Open File Report 65-124, 35p.

Plafker, G. 1965. Tectonic deformation associated with the 1964 Alaska earthquake. Science 148(3678):1675-1687.

Hansen, W. R. 1967. The Alaska earthquake of 1964. Nature 215:348-351. doi: 10.1038/215348a0

Page, R. 1968. Aftershocks and microaftershocks of the great Alaska earthquake of 1964. Bulletin of the Seismological Society of America. 58(3):1131-1168.

Atwater, B.F., D. K. Yamaguchi, S. Bondevik, W. A. Barnhardt, L. J. Amidon, B. E. Benson, G. Skjerdal, J. A. Shulene, and F. Nanayama. 2001. Rapid resetting of an estuarine recorder of the 1964 Alaska Earthquake. Bulletin of the Geological Society of America 113:1193–204. doi: 10.1130/0016-7606(2001)113<1193:RROAER>2.0.CO;2

Zweck, C. J. T. Freymueller, and S. C. Cohen. 2002. Three-dimensional elastic dislocation modeling of the postseismic response to the 1964 Alaska earthquake. Journal of Geophysical Research: Solid Earth 107(B4):ECV 1-1–ECV 1-11. doi: 10.1029/2001JB000409

Zong, Y., I. Shennan, R. A. Combellick, S. L. Hamilton, and M. M. Rutherford. 2003. Microfossil evidence for land movements associated with the AD 1964 Alaska earthquake. The Holocene 13(1):7-20. doi: 10.1191/0959683603hl590rp

Doser, D. I., N. A. Ratchkovski, P. J. Haeussler, and R. Saltus. 2004. Changes in crustal seismic deformation rates associated with the 1964 Great Alaska earthquake. Bulletin of the Seismological Society of America, 94(1):320-325. doi: 10.1785/0120030096

Ichinose, G., P. Somerville, H. K. Thio, R. Graves and D. O'Connell. 2007. Rupture process of the 1964 Prince William Sound, Alaska, earthquake from the combined inversion of seismic, tsunami, and geodetic data. Journal of Geophysical Research: Solid Earth 112(B7) doi: 10.1029/2006JB004728

Suito, H. and J.T. Freymueller. 2009. A viscoelastic and afterslip postseismic deformation model for the 1964 Alaska earthquake. Journal of Geophysical Research: Solid Earth 114(B11) doi: 10.1029/2008JB005954

Suleimani, E., D. J. Nicolsky, P. J. Haeussler, and R. Hansen. 2011. Combined effects of tectonic and landslide-generated Tsunami Runup at Seward, Alaska during the Mw 9.2 1964 earthquake. Pure and Applied Geophysics 168(6-7):1053-1074. doi: 10.1007/s00024-010-0228-4

Barnes, D. F. 2012. Gravity changes during the Alaska earthquake. Journal of Geophysical Research 71(2):451-456. doi: 10.1029/JZ071i002p00451

Davies, K. and D. M. Baker. 2012. Ionospheric effects observed around the time of the Alaskan earthquake of March 28, 1964. Journal of Geophysical Research 70(9):2251-2253. doi: 10.1029/JZ070i009p02251

Dziewonski, A. M. and F. Gilbert. 2012. Observations of Normal Modes from 84 Recordings of the Alaskan Earthquake of 1964 March 28. Geophysical Journal International 27(4):393-446. doi: 10.1111/j.1365-246X.1972.tb06100.x

Johnson, J. M., K. Satake, S. R. Holdahl, and J. Sauber. 2012. The 1964 Prince William Sound earthquake: Joint inversion of tsunami and geodetic data. Journal of Geophysical Research: Solid Earth 101(B1):523-532. doi: 0.1029/95JB02806

Kanamori, H. 2012. The Alaska Earthquake of 1964: Radiation of long-period surface waves and source mechanism. Journal of Geophysical Research 75(26):5029-5040. doi: 10.1029/JB075i026p05029

Leonard, R. S. and R. A. Barnes, Jr. 2012. Observation of ionospheric disturbances following the Alaska earthquake. Journal of Geophysical Research 70(5):1250-1253. doi: 10.1029/JZ070i005p01250

Piersanti, A., G. Spada, and R. Sabadini. 2012. Global postseismic rebound of a viscoelastic Earth: Theory for finite faults and application to the 1964 Alaska earthquake. Journal of Geophysical Research: Solid Earth 102(B1):477-492. doi: 10.1029/96JB01909

Plaker, G. 2012. Alaskan earthquake of 1964 and Chilean earthquake of 1960: Implications for arc tectonics. Journal of Geophysical Research 77(5):901-925. doi: 10.1029/JB077i005p00901

Reimnitz, E. and N. F. Marshall. 2012. Effects of the Alaska earthquake and tsunami on recent deltaic sediments. Journal of Geophysical Research

Sykes, L. R. 2012. Aftershock zones of great earthquakes, seismicity gaps, and earthquake prediction for Alaska and the Aleutians. Journal of Geophysical Research 76(32):8021-8041. doi: 10.1029/JB076i032p08021

Stauder, W. and G. A. Bollinger. 2012. The focal mechanism of the Alaska earthquake of March 28, 1964, and of its aftershock sequence. Journal of Geophysical Research 71(22):5283-5296. doi: 10.1029/JZ071i022p05283

Brocher, T.M., Filson, J.R., Fuis, G.S., Haeussler, P.J., Holzer, T.L., Plafker, G., and Blair, J.L., 2014, The 1964 Great Alaska Earthquake and tsunamis—A modern perspective and enduring legacies: U.S. Geological Survey Fact Sheet 2014–3018, 6 p., http://dx.doi.org/10.3133/fs20143018.

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The Alaska Earthquake Alliance, which is composed of member groups and organizations, coordinates earthquake awareness and preparedness activities in Alaska. The Alliance is a part of a statewide alliance linking organizations and individuals that provide earthquake information and services. You, or your organization can JOIN US.

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Last modified: September 30, 2014