Major damage occurred in the densely populated city of Long Beach on the south-facing coast of Los Angeles County.

The magnitude of the earthquake is considered medium, but a significant amount of damage occurred due to unfavorable geological conditions (landfill, water-soaked alluvium) combined with poorly constructed buildings.

[12] On March 20, 2008, a Los Angeles Times article stated that "the 1933 quake changed the landscape, leading to improved school construction standards and a heightened awareness of earthquake risks.

"[13] Among other buildings, the La Grande Station, the main Los Angeles terminal of the Atchison, Topeka, and Santa Fe Railroad, was heavily damaged.

[15] Only 30 days after the earthquake, Governor James Rolph Jr. signed the Field Act to govern the planning, design and construction of public school buildings.

The committee was chaired by CalTech physicist Robert Millikan, and included architects John C. Austin and Sumner Hunt.

To support the World War II efforts, Long Beach created naval yards and increased the number of aircraft produced.

[20] A 2016 press release by the United States Geological Survey indicates that research shows the 1933 Long Beach earthquake may have been man-made, caused by oil and gas extraction underneath the city.

[25] Within the Los Angeles depositional basin, northwest-trending groups of faulted anticlines were viewed to be caused by oil and gas extraction underneath the city.

The extraction of oil and gas produces salty water,[clarification needed] adding stress to faults, causing earthquakes.