Historic Earthquakes
Prince William Sound, Alaska
1964 March 28 03:36 UTC
1964 March 27 05:36 p.m. local time
Magnitude 9.2
Largest Earthquake in Alaska
Damage Photos
House displaced by compressional ridge formed at toe of L Street landslide
Anchorage district. Cook Inlet region, Alaska. 1964.
Control tower at Anchorage International Airport, collapsed by earthquake shaking. Anchorage district, Cook Inlet region, Alaska.
Close-up view of the damage created at the piers of the
"Million Dollar" truss bridge by movement of the truss
spans during the earthquake. Note the bent base plates,
the sheared 2-inch diameter bolts and the overturned rocker bars.
The Turnagain Heights landslide in Anchorage, occurred along a
steep bluff fronting Knik Arm of Cook Inlet. Its length, which
is parallel to the bluff, was about 1.5 miles; its width was
about .25 to .50 miles. This landslide reduced to rubble many
of the finer homes of the city. Failure here, and in the
"L" Street, Fourth Avenue, and Government Hill landslides in
Anchorage occurred on horizontal or near horizontal slip surfaces
in the Bootlegger Cove Clay, a marine silt of Pleistocene age.
Alaska.
This reinforced concrete deck of highway bridge across Twenty
Mile River near Turnagain Arm of Cook Inlet fell into the
river during the earthquake; the adjacent steel railroad
bridge survived with only minor damage. Both bridges were
founded on thick deposits of soft alluvium and tidal flat
mud, and were subjected to severe seismic vibration.
During the earthquake some of the concrete deck sections
hit the underlying wood pilling with sufficient force to
drive the bare ends of the wood piles through the concrete
deck.
The marquee of the Denali Theater, which was in the graben
of the Fourth Avenue landslide in Anchorage, subsided
until it came to rest on the sidewalk in front of the
theater, which was on ground that was not involved in the
landslide.
This truck at Lowell Point, 2 miles from Seward, was bent
around a tree by the surge waves generated by the
underwater landslides along the Seward waterfront. The
truck was about 32 feet above water level at the time of
the earthquake.
Collapse of Fourth Avenue near C Street, Anchorage, due to
earthquake caused landslide. Before the earthquake, the
sidewalk at left, which is in the graben, was at street level
on the right. The graben subsides 11 feet in response to 14
feet of horizontal movement. Anchorage district, Cook Inlet region,
Alaska. 1964.
Photos from the Earth Science Photographs from the U.S. Geological Survey Library, by Joseph K. McGregor and Carl Abston, U.S. Geological Survey Digital Data Series DDS-21, 1995.
