earthquake safety 2-4. earthquake risk determined by locating where faults are active and where past...

Earthquake safety

2-4

Earthquake risk

• Determined by locating where faults are active and where past earthquakes have occurred

• High risk on West coast because North American and Pacific plates meet nearby

How Earthquakes Cause Damage

• Shaking• Liquefaction• Aftershocks• Tsunamis

Shaking

• Produced by seismic waves• Can trigger landslides or avalanches• Damage and destroy buildings• Type of rock and soil determines how much

the ground shakes– Loose soil shakes more violently than solid rock

Liquefaction

• Earthquakes violent shaking turns loose, soft soil into mud

• Likely where soil is full of moisture

Aftershocks

• Earthquake that occurs after a larger earthquake in the same area

• May strike hours, days, or months later

Tsunamis

• Caused when an earthquake jolts the ocean floor causing it to rise slightly and push water out of the way

• Height of wave is low in the open ocean• Grows as it reaches shore

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Protecting Yourself

• Earthquake kit-canned food, water, first aid• Drop, cover, hold• Indoors: – Crouch under table or desk or against an inner wall; cover

head and neck with arms– Avoid windows, mirrors, wall hangings, unstable furniture

• Outdoors:– Move to open area– Sit down– Avoid vehicles, power lines, trees, buildings

Designing Safer Buildings

• Reinforce or strengthen walls• Anchor to solid rock below soil• Build base isolated buildings with shock

absorbing rubber pads or springs• Flexible joints in gas and water lines• Automatic shut off valves