A 7.1 magnitude earthquake struck western Washington on April 13, 1949. It had its epicenter near the coast between Olympia and Tacoma, and it was felt strongly in Washington, Oregon, Idaho, and British Columbia. It was the most powerful earthquake to strike Puget Sound since 1700. Eight people were killed, and dozens of others were seriously injured.

The most severe damage occurred along an eighty-mile stretch of coast from Seattle to Chehalis. Approximately 40% of Chehalis' commercial and residential buildings were damaged, and more than 10,000 chimneys in Washington needed to be repaired. The total cost of the damage was $25 million.

Eight buildings in Olympia, the state capital, were damaged. North of Olympia, a large sandy spit jutting into Puget Sound vanished. The earthquake in Portland resulted in rockslides and building cracks. Earthquake damage in Seattle included the strongest ground shaking of the quake. Damage to well-built structures was significant, while damage to poorly built structures was extensive. Some structures collapsed. Chimneys, factory stacks, columns, and monuments were destroyed. People had difficulty driving because heavy furniture had overturned.

Three schools were severely damaged and were eventually condemned. The large brick gable over the main entrance at Lafayette Elementary School in West Seattle collapsed. Due to shifting earth, three bridges crossing the Duwamish River were jammed shut. Near Green Lake, cracks appeared in the earth. Throughout the city, numerous brick walls collapsed, fractured, or bulged. They were all sentenced to death.

Many Seattle homes built on filled areas were demolished, and the ground in some places turned to quicksand, causing floors to crack and basements to fill with silt. Cracks appeared in the ground, some of which spewed water six feet high. Gas lines in Seattle burst in a hundred places, but no fires broke out. This has been a common issue in coastal cities along the United States' coasts. San Francisco's experience in 1906 and subsequent earthquakes is a classic example of the problem.

Cities expand their footprint by reclaiming sea-level land. New foundations are rarely designed to support new buildings. As a result, when an earthquake occurs, liquefaction occurs as a result of the shaking, and the former surface beneath buildings becomes a muddy mass incapable of supporting any weight. A 200-foot-high cliff collapsed into Puget Sound south of Seattle, near Tacoma. Several railway bridges were thrown out of alignment in the same area.