San Francisco EarthquakeSan Francisco Earthquake19891989

Loma PrietaLoma Prieta

What happened?What happened?

• October 17th 1989 • 5.04pm• 20 seconds duration• Magnitude 7• Intensity IX• Enormous amounts of damage

DamagesDamages

• Cost $10 billion– $2 billion in San Francisco

• Damages– 18000 homes– 2500 other buildings

• Destroyed– 963 homes– 147 other buildings

CasualtiesCasualties

• Over 3700 injuries

• 62 deaths

• 12000 missing

Catastrophic EventsCatastrophic Events

• Collapse of theInterstate 880

• Collapse of the San Francisco-Oakland Bay bridge

• Liquefaction– Building collapse

in Marina District

• Landslides

• Damage to Epicentre locality

CauseCause

• San Andreas Fault

– Plate Boundary

– 800 miles across California

• Unusual San Andreas activity

– Horizontal Slip

– Thrusting• Result 70° dip • to southwest

Earthquake HistoryEarthquake History

• Long history of earthquakes– First recorded quake in 1769– 1989 quake repeat of 1865– First large earthquake since 1906

• Irregular pattern to earthquakes– Many in one year (e.g. 1971)– Then no significant ones for several years

PredictionPrediction

• Earthquake was predicted

– Little significant activity

– Several over 5 in last 2 years

Damage PreventionDamage Prevention

• Earthquake Research

• Improved building design

– Reinforcements– Less rigid– Movement

• Very costly– Cant rebuild whole city

• Research is never complete– Full prevention can

never occur