California Earthquakes
Through an historical perspective
San Francisco
Loma Prieta
San Fernando
Northridge
Long Beach
1933 Long Beach Earthquake
• March 10,1933, 5:54 PM• Mw = 6.4• Right lateral slip along Newport-Inglewood
Fault• No surface rupture• 120 fatalities• 50 million dollars in damage
Newport-Inglewood Fault
Franklin Junior High School120 schools destoyed; 70 damaged
Collapse of unreinforced masonry structures
Pile of Bricks
Collapse of Unreinforced Masonry School
• 5 teachers killed• Field Act passed• Gave the state authority to supervise
structures built for schools
1971 San Fernando Earthquake
• February 9, 1971, 6:01 AM• Thrust fault dipping to the north• 12 miles of surface rupture• Maximum displacement of 6 feet• 65 fatalities• 500 million dollars of damage
Location, San Fernando Valley
• Cross-sections of the San Fernando and Northridge earthquakes.
San Fernando Valley Earthquakes
Dam: end terminus of the Los Angeles water system; 80 % of LA’s water
Shaking caused landslide
80,000 people below
House over Garage
Veterans Hospital
Olive-View Hospital (soft story collapse)
1989 Loma Prieta Earthquake
• October 17, 1989; 5:04 PM• Mw = 6.9• Oblique movement on the San Andreas Fault• Maximum offset of 3-4 feet• ~ 25 miles of fault plane movement• 15 seconds of shaking• 6-10 billion dollars of damage
Earth Materials
The Northridge Earthquake
• January 17. 1994, 4:31 am• Epicenter: 1 mile SW of Northridge• Magnitude: Mw 6.7• Type of fault: blind thrust, the Pico Thrust• Hypocenter: 18.4 km• Deaths: 57• 1500 seriously injured• Cost: 15 billion dollars
The mountains are the surface expression of the fault. This fault was unknown before this earthquake.
Northridge Earthquake
Collapse of Soft Story
Failure of Reinforced Concrete Structures
Rebuilt Olive-view Hospital
Success of retrofitted URM
structures
Change in how earthquake insurance is distributed.