Notable Earthquake of the Week

Long Beach M6.4 Earthquake  

In the evening of March 10, 1933, a strong earthquake registering M6.4 occurred along the Southern California coast south of Los Angeles. Although the 5:54 p.m. temblor was centered near the border of Huntington and Newport Beach, Long Beach suffered the most damage, hence the name, the Long Beach Earthquake.

The quake occurred on the prominent Newport- Inglewood-Rose Canyon fault zone, a right-lateral strike-slip fault system that parallels the coastline from San Diego to north of Inglewood. A strong aftershock sequence lasted for nearly three years and consisted over 120 tremors registering M4 or stronger, including 10 in the M5 range - six of which occurred within 24 hours of the main jolt. The largest aftershock measured M5.5 and occurred just before 11 p.m. the night of the disaster and contributed to additional damage.

The temblor was extremely violent, registering shaking intensities of XI on the Modified Mercalli scale (a relative shaking intensity rating from 1-12 shown in Roman numerals). Numerous buildings were severely damaged, including several schools and government buildings. Fortunately, many schools were out of session at that time of day which saved countless lives. However, at least 120 people lost their lives and damage was estimated at $50 million dollars (1933 figures). More damage photos.

In the wake of the immense public outcry against shoddy construction practices, strong legislation was passed which significantly upgraded building construction standards throughout the State. Most notable was the passage of the Field Act, which gave the State Division of Architecture authority and responsibility for approving design and supervising construction of public schools.

Of the 500+ school buildings that meet the new construction standards during the 1971 Sylmar earthquake, none sustained significant structural damage. But 50 of the older schools that did not pass seismic-resistance requirements suffered substantial damage.

 
Seismo-Watch Earthquake Reports

Track earthquake activity with the Seismo-Watch Earthquake Reports. Click here or on any of the reports below.

You can also track activity in Central California with the Brief CCA Earthquake Report and the Western Basin and Range, including the very active Mammoth Lakes region, with the Brief WGB Earthquake Report.

Seismo-Watch Alert Bulletins are a great way to be informed right away when significant earthquakes occur.