California Earthquakes Through an historical perspective San

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 School 120 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

San Fernando Valley Earthquakes • Cross-sections of the San Fernando and Northridge 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

Northridge Earthquake The mountains are the surface expression of the fault. This fault was unknown before this 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.