1964 Alaska earthquake

On March 27, 1964, at 5:36 p.m. AKST (March 28, at 3:36 a.m. UTC), a fault between the Pacific and North American plates ruptured near College Fjord in Prince William Sound. The epicenter of the earthquake was north of Prince William Sound, east of Anchorage and west of Valdez. The focus occurred at a depth of approximately . Ocean floor shifts created large tsunamis (up to in height), which resulted in many of the deaths and much of the property damage. Large rockslides were also caused, resulting in great property damage. Vertical displacement of up to occurred, affecting an area of within Alaska. Studies of ground motion have led to a peak ground acceleration estimate of 0.14–0.18 g. Uplift occurred across from southern Kodiak to Prince William Sound and further east of the sound. The maximum uplift was in Montague Island, where the ground was raised relative to sea level. The uplift also affected Kodiak, Sitkalidak, and Sitkinak islands. Subsidence was observed for from north and west of the sound, in Chugach Mountains, most of Kenai Peninsula, and almost all the Kodiak Island group. ==The tsunami==

Two types of tsunami were produced by this subduction zone earthquake. There was a tectonic tsunami produced in addition to about 20 smaller and local tsunamis. These smaller tsunamis were produced by submarine and subaerial landslides and were responsible for the majority of the tsunami damage. Tsunami waves were noted in over 20 countries, including Peru, New Zealand, Papua New Guinea, Japan, Mexico, and in the continent of Antarctica. The largest tsunami wave was recorded in Shoup Bay, near Valdez, Alaska, with a height of about . ==Death toll, damage, and casualties==

between Point Woronzof and Fish Creek, causing substantial damage to numerous homes in the Turnagain-By-The-Sea subdivision. department store in Anchorage in 1964, following the earthquake As a result of the earthquake, 139 people are believed to have died: Fifteen died as a result of the earthquake itself and another 124 died from the subsequent tsunamis in Alaska, Oregon, and California. Five died from the tsunami in Oregon, and 13 died from the tsunami in California, mostly in or near Crescent City. Property damage was estimated at $116 million The Government Hill school suffered from the Government Hill landslide, leaving it in two jagged, broken pieces. Land overlooking the Ship Creek valley near the Alaska Railroad yards also slid, destroying many acres of buildings and city blocks in downtown Anchorage. Most other areas of the city were only moderately damaged. The concrete control tower at Anchorage International Airport collapsed, killing the controller on the top floor, as well as trapping two cooks on the first floor, who were later rescued. One house on W. 10th Avenue suffered peripheral damage, but only one block away the recently completed (and still unoccupied) Four Seasons Building on Ninth Avenue collapsed completely, with the concrete elevator shafts sticking up out of the rubble like a seesaw. The hamlets of Girdwood and Portage, located southeast of central Anchorage on the Turnagain Arm, were destroyed by subsidence and subsequent tidal action. Girdwood was relocated inland and Portage was abandoned. About of the Seward Highway sank below the high-water mark of Turnagain Arm; the highway and its bridges were raised and rebuilt in 1964–66. Elsewhere in Alaska , as shown in this 1974 photo Most coastal towns in the Prince William Sound, Kenai Peninsula, and Kodiak Island areas, especially the major ports of Seward, Whittier and Kodiak were heavily damaged by a combination of seismic activity, subsidence, post-quake tsunamis and/or earthquake-caused fires. Valdez with 32 dead was not totally destroyed, but after three years, the town relocated to higher ground west of its original site. Some Alaska Native villages, including Chenega and Afognak, were destroyed or damaged. The earthquake caused the ballistic missile detection radar of Clear Air Force Station to go offline for six minutes, the only unscheduled interruption in its operational history. Near Cordova, the Million Dollar Bridge crossing the Copper River also suffered damage, with Span #4 slipping off its pylon and collapsing. The community of Girdwood was also confined to the southern side of the Seward Highway when water rushed into Turnagain Arm and flooded or destroyed any buildings left standing to the north of the highway. Only the ground immediately along the highway and that on the north side of the road dropped, prompting geologists to speculate that Girdwood may rest upon an ancient cliff face covered by thousands of years of sediment and glacial deposits. Canada A wave reached Prince Rupert, British Columbia, just south of the Alaska Panhandle, about three hours after the earthquake. The tsunami then reached Tofino, on the exposed west coast of Vancouver Island, and traveled up a fjord to hit Port Alberni twice, washing away 55 homes and damaging 375 others. The towns of Hot Springs Cove, Zeballos, and Amai also saw damage. The damage in British Columbia was estimated at CA$10 million ($ in Canadian dollars or $ in US dollars). Elsewhere " that was killed and preserved by salt water along with ruined buildings at the site of the former town of Portage, 2011 Ten people were killed by the tsunami in Crescent City, California, and one other man was killed near Requa, California after being swept out to sea while fishing in the Klamath River. Four children were killed while camping with their parents on the Oregon coast at Beverly Beach State Park. An additional death that is sometimes attributed to the tsunami took place in Bolinas, California; a fisherman wading into a seaside channel at Duxbury Point was swept into the ocean by a strong surge that took place 13 hours after the initial tidal surge. Crescent City was particularly hard-hit, with 30 blocks destroyed, representing half of the city's waterfront business district. The total damage to Crescent City was estimated at $7.4 million ($76 million in 2025 dollars). Other coastal towns and harbors in the Pacific Northwest, California, and Hawaii were damaged, often extensively. Damage to harbors and boats occurred as far south as Long Beach, California. Effects of the earthquake were even noted as far east as Freeport, Texas, where tide gauges recorded waves similar to seismic surface waves. Seiches were detected in wells in countries around the world, including England, Namibia, and Australia. ==Aftershocks==

There were hundreds of aftershocks in the first weeks following the main shock. In the first day alone, eleven major aftershocks with a magnitude greater than 6.0 were recorded. Nine more struck over the next three weeks. In all, thousands of aftershocks occurred in the months following the quake, and smaller aftershocks continued to strike the region for more than a year. ==Recovery efforts==

Alaska had never experienced a major disaster in a highly populated area before, and had very limited resources for dealing with the effects of such an event. In Anchorage, at the urging of geologist Lidia Selkregg, the City of Anchorage and the Alaska State Housing Authority appointed a team of 40 scientists, including geologists, soil scientists, and engineers, to assess the damage done by the earthquake to the city. The team, called the Engineering and Geological Evaluation Group, was headed by Dr. Ruth A. M. Schmidt, a geology professor at the University of Alaska Anchorage. The team of scientists came into conflict with local developers and downtown business owners who wanted to immediately rebuild; the scientists wanted to identify future dangers to ensure that rebuilt infrastructure would be safe. The team produced a report on May 8, 1964, just a little more than a month after the earthquake. The United States military, which has a large active presence in Alaska, also stepped in to assist within moments of the end of the quake. The U.S. Army rapidly re-established communications with the lower 48 states, deployed troops to assist the citizens of Anchorage, and dispatched a convoy to Valdez. On the advice of military and civilian leaders, President Lyndon B. Johnson declared all of Alaska a major disaster area the day after the quake. The U.S. Navy and U.S. Coast Guard deployed ships to isolated coastal communities to assist with immediate needs. Bad weather and poor visibility hampered air rescue and observation efforts the day after the quake, but on Sunday the 29th the situation improved and rescue helicopters and observation aircraft were deployed. She was effectively designated as the public safety officer by the city's police chief. In the longer term, the U.S. Army Corps of Engineers led the effort to rebuild roads, clear debris, and establish new townsites for communities that had been completely destroyed, at a cost of $110 million. The West Coast and Alaska Tsunami Warning Center was formed as a direct response to the disaster. Federal disaster relief funds paid for reconstruction and financially supported the devastated infrastructure of Alaska's government, spending hundreds of millions of dollars that helped keep Alaska financially solvent until the discovery of significant oil deposits at Prudhoe Bay. At the order of the U.S. Defense Department, the Alaska National Guard established the Alaska Division of Emergency Services to respond to any future disasters. ==See also==