1. 13A.3 – Natural Hazards

2. Do Now
What are four main earthquake hazards in California?

3. Do Now What are four main earthquake hazards in California? Tsunamis
Seismic Shaking
Liquefaction
Landslides

4. Key Words
Hazard

5. Vocab Words
Natural Hazard
Volcanic Field

6. What is a Natural Hazard?
An event that results from Earth processes and that can cause damage and endanger human life.
Earthquakes, landslides, tsunamis, shaking, liquefaction, volcanoes, mudflows and flooding in CA
Tornadoes, hurricanes, etc. in other states

7. California’s Earthquake Hazards
Hundreds of earthquakes each day in CA
Most are so weak they are generally not felt.
Earthquakes can lead to numerous other natural hazards
Tsunamis, Seismic Shaking, Liquefaction and Landslides.

8. Tsunamis
In the past 200 years, more than a dozen locally generated tsunamis have struck the CA coastline.
Not all are locally such as when a major earthquake in Alaska in 1964 produced a tsunami that struck Crescent City hours later and killed 11 people.

9. Seismic Shaking
The amount of shaking from one location to another varies.
The further from the epicenter the less shaking that will occur.
Rock and soil conditions also play a part.

10. Liquefaction
Liquefaction occurs when water-soaked soil turns to a thick, soupy liquid during an earthquake.

11. When loose rock and soil on a slope moves resulting from an earthquake.
Mostly on steep slopes
More likely after fires or droughts since plants are damaged and they typically hold the soil in place.
Landslides

12. California's Volcanic Hazards
Natural hazards that result from volcanic activity are volcanic ash, lava flows and volcanic gases.
The Cascade Range runs through CA, in northern CA.
Most are dormant but can still erupt at any given time.
All composite cones and has the potential to cause volcanic ash and lava flows.

13. California's Volcanic Hazards
Volcanic Field:
An area that is covered by volcanic rocks.
Eastern and central parts of CA.
Long Valley Caldera is an example of a volcanic field.
High concentrations of Carbon Dioxide gases are currently leaking in this area; causing plants, animals and people to die. Especially Mammoth Mountain.

14. California's Storm Hazards
Two main storm-related hazards in CA are mudflows and flooding.
The dry conditions in southern CA make it very susceptible to mudflows and flooding, especially when precipitation is greater than normal.

15. Mudflows
Masses of very wet soil, and sometimes rock, that flows quickly downhill.
These are common in southern CA during and after severe rainfall.
Usually on a steep slope.

16. Flooding There are flash floods in areas that have been in droughts.
Flooding, especially flash flooding is extremely dangerous because the water rises and moves rapidly.

17. Group Challenge Question
What factors are responsible for most of the floods in California?