California’s California’s natural natural hazardshazards

Earthquake hazards

tsunamis, seismic shaking, liquefaction, and landslides

tsunamis• Form when the ocean

floor shifts in an earthquake or undersea landslide.

• The wave travels 600mph

• Coastal warning systems are in place.

• If you see the water go out…RUN!

Crescent City, 1964 after Alaska earthquake

Seismic shaking

• Amount of shaking depends on the soil, buildings, distance from epicenter and intensity of the quake.

1868 quake on the Hayward fault

Other EQ hazards

• Liquifaction: water-soaked soil turns into a liquid.

• Landslides: on steep slopes, rocks and dirt come loose.

• Other causes:– Excess rain– After fires– After drought

Anchorage, Alaska 1964

Volcanic hazards

• Include volcanic ash, lava flows, and volcanic gases.

• Volcanic fields can become active again.

• Toxic CO2 from Mammoth Mtn. is killing the forest in this volcanic area east of the Sierras.

Mt. Lassen 1914-1917

Storm hazards

• Mudflows: a mass of very wet soil flows downhill – can move 60 km/hr.

• Flooding: too much rain or melting snow.

• Failing levees in rivers and deltas

• Flash floods in deserts

Be prepared for an earthquake

• Getting together an EQ safety kit.

• Preparing your home for an earthquake

• Know how to turn off the gas supply.

Review

1. What is the name of a large wave caused by an earthquake?

2. Name 3 storm hazards.

3. Name 3 things that affect seismic shaking.