MT 6: CALIFORNIA GEOLOGYLT 1: Natural Hazards

Why are we studying CA Geology?

• We live in California and it is a state standard.

• California has major, unique geological features and history.

• California is located on the west coast of the United States. The United States is part of the North American continent.

• The North American plate meets the Pacific plate directly under the crust of our state.

• California is in a zone of major plate movement and activity.

• California was formed as a result of this tectonic plate movement for thousands of years.

• Also California has been carved from wind, water, ice, and erosion on the surface of the Earth to form our unique landscape.

So what is the unique landscape of California?

• Very tall and large mountain range called the Sierra Nevada Range.

• Large Eastern deserts.

• Located directly in contact with the largest ocean in the world called the Pacific Ocean.

• Northern California is cooler and receives more precipitation.

• Southern California is warmer and receives less precipitation.

CA Natural Hazards

• The most dangerous events and natural hazards that result from them for different areas of Ca are

• Storms

• Earthquakes

• Volcanoes

CA: Natural Hazards

•What is the importance?•Natural hazards

can cause damage

and endanger human life

CA Natural Hazards

•Storms (excess of Precipitation)

-Winter storms typically

bring rain to lower elevations and snow to the mountains.

-Two main storm-related hazards in California are mudflows and flooding.

CALIFORNIA’S STORM HAZARDS• MUDFLOWS-

• A mudflow often starts in a depression on a steep hillside. • At first, a mudflow moves fairly slowly-about 16 kilometers per hour. • But as the mud engulfs more and more loose debris, it picks up

speed. • At top speed, a mudflow can move nearly 60 kilometers per hour,

destroying everything in its path.

CALIFORNIA’S STORM HAZARDS• FLOODING-

• Flooding Is another California storm hazard. • Some of the state’s floods are regional floods. • Some flooding in California occurs when excessive rainfall causes

dams and levees to fail.

CA Natural Hazards

• Earthquakes-When Californian’s thinks of Natural Hazards, Earthquakes are the first to come in mind.

-Hundreds of earthquakes occur each day in California.

-But the stronger Earthquakes, especially quakes with a magnitude of 5 or higher can be dangerous.

CALIFORNIA’S EARTHQUAKE HAZARDS

• TSNUNAMIS – • Is a wave formed when the ocean floor shifts suddenly during an earthquake. • As a Tsunami nears land and begins to break, the Tsunami can grow to enormous

size.• A Tsunami gains speed as it gets closer to land• A Tsunami acts like a wall of water

CALIFORNIA’S EARTHQUAKE HAZARDS

• SIESMIC SHAKING – • Is a measure of how much ground movement occurs during an earthquake. • Seismic Shaking reflects the behavior of an earthquake’s seismic waves. • Can cause buildings, freeways and structures to collapse

CALIFORNIA’S EARTHQUAKE HAZARDS

• LIQUEFACTION –• Occurs when water-soaked soil turns to a thick, soupy liquid during an earthquake• As liquefaction takes place, buildings and other structures quickly collapse into soft

mud.

CALIFORNIA’S EARTHQUAKE HAZARDS

• LANDSLIDES – • Occur on steep slopes where sediment is loose or where rocks are highly

fractured. • Earthquakes can also cause landslides in areas that are underlain by weak

soils.

CA Natural Hazards•Volcanoes

• Many are surprised to learn that

parts of the state are at risk from

volcano‘s.

CALIFORNIA’S VOLCANIC HAZARDS

• VOLCANIC ASH – • the dust that comes off the burning rock of the volcano.

• Can be harmful to plant, animal and human respiratory system

• Can block incoming solar radiation that is needed to survive

CALIFORNIA’S VOLCANIC HAZARDS• LAVA FLOWS – • Lava flow is produced when lava breaks through the surface of a volcano and starts to travel down the sides.

• Lava flows can destroy whole villages and help create new land masses.

CALIFORNIA’S VOLCANIC HAZARDS• VOLCANIC GASES-• Magmatic gases and high-temperature volcanic gases,

• Low-temperature volcanic gases and hydrothermal systems,

• Non-explosive volcanic gas release

WHICH HAZARD DO YOU THINK EFFECTS YOU THE MOST?