EarthquakeEarthquake

CH 5 Prentice Hallp.154-159

CH 5 Prentice Hallp.154-159

SafetySafetyHazards andHazards and

How Earthquakes Damage

• Severe shaking produced by seismic waves can damage or destroy buildings and bridges.

• Topple utility poles• Fracture gas and water mains.• S-Waves – side to side and

up/down motion can tear a building apart.

Local Soil Conditions

• Loose soil shakes more violently than surrounding rock.

• A house built on solid rock will shake less than a house build on sandy soil.

Liquefaction

• Occurs when the violent shaking suddenly turns loose, soft soil into liquid mud.– Likely where soil is full of moisture.– Buildings sink and pull apart.– Can trigger landslides.

Aftershocks

• Smaller earthquakes that follow large earthquakes.

• Up to 1,000 per day can strike

• May strike hours, days or months later.

Tsunamis

• Huge ocean waves caused by underwater earthquakes or landslides.

• Displaces water and forms a large ocean wave.– Waves travel at speeds up

to 750km/h or 500mph.– Wave height is low until it

reaches land.• Six story building (30ft)

• Threatens coast lines.

Tsunamis

2004 Tsunami

Making Buildings Safer

• To reduce damage new buildings must be made stronger and more flexible.

• Older buildings must be modified to withstand stronger quakes.

Choice of Location

• Steep slopes- pose the danger of landslides.

• Filled land (loose soil) can shake violently

• Avoid building near faults.

Construction Methods

• Anchor buildings and road supports into solid rock below.

• Base-isolated buildings– Rests on shock absorbing

rubber pads or springs.– Allows the building to

move back and forth gently.

Protecting Yourself

• Most danger is due to falling objects.

• Stop, Cover and Hold

• Stay along an inner wall and cover your head and neck.

Protecting Yourself

• Avoid windows, mirrors and furniture that may fall over.

• Make an earthquake kit- with first aid supplies, canned food and water.

Protecting Yourself

• If outside-– Move to an open area away

from falling objects:• Power lines• Trees• Buildings

– Sit down to avoid being thrown down.

Earthquake Safe House

Earthquake Supplies

Earthquake Quizzes