The 1964 Alaskan earthquake… …also known as the Great Alaskan Earthquake, the Portage Earthquake and the Good Friday Earthquake, lasted nearly four minutes on Good Friday, March 27, 1964. This megathrust earthquake attacked south-central Alaska and caused ground fissures, collapsing structures, and tsunamis. It was the most powerful recorded earthquake in U.S. and North American history, at a shocking magnitude of 9.2, and the second most powerful in the entire world, only to the horrible1960 Valdivia earthquake, also known as the Great Chilean Earthquake.
Wikipedia states…“The powerful earthquakeproduced earthquake liquefactionin the region. Ground fissures andfailures caused major structuraldamage in several communities,much damage to property andseveral landslides. Anchorage (myhometown) sustained greatdestruction or damage to manyinadequately engineered houses,buildings, and infrastructure (pavedstreets, sidewalks, water and sewermains, electrical systems, and otherman-made equipment), particularlyin the several landslide zones alongKnik Arm. Two hundred milessouthwest, some areas near Kodiakwere permanently raised by 30 feet(9.1 m). Southeast of Anchorage,areas around the head ofTurnagain Arm near Girdwood andPortage dropped as much as 8 feet(2.4 m), requiring reconstructionand fill to raise the Seward Highwayabove the new high tide mark.”
The damage…Most damage occurred inAnchorage, 75 miles northwest of theepicenter. Luckily, Anchorage wasnot hit by tsunamis. But downtownAnchorage was still severelydamaged, and parts of the city builton sandy bluffs overlying "BootleggerCove clay" near Cook Inlet, mostnotably the Turnagain neighborhood,suffered landslide damage.The neighborhood lost a total of 75houses in the landslide, and thedestroyed area has since beenturned into Earthquake Park.The Government Hill school was left intwo jagged, broken pieces due to alandslide. Land overlooking the ShipCreek valley near the Alaska Railroadyards also slid, destroying many acresof buildings and city blocks indowntown Anchorage.Most other areas of the city wereonly moderately damaged. The 60-foot concrete control tower atAnchorage International Airport wasnot engineered to withstandearthquake activity and actuallycollapsed, killing one employee.
Interesting tidbits… Valdez, AK was not totally destroyed, but after three years, the town relocated to higher ground 7 km (4 mi) west of its original site The earthquake caused the Cold-War era 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 collapsed Other towns along the U.S. Pacific Northwest and Hawaii were damaged Minor damage to boats reached as far south as Los Angeles Several fishing boats were sunk in Louisiana, and water sloshed in wells in Africa
Aftershocks…There were literallythousands of aftershocksfor three weeks,following the major, life-shattering earthquake.On the first day alone,eleven scary aftershockswere recorded with amagnitude greater than6.2. Nine more ensuedover the next threeweeks.More than a year later,the aftershocks stopped.