Download MT 9: CaLIFORNIA gEOLOGY

MT 6:
CALIFORNIA GEOLOGY
LT 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.
• 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.
• 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.
–
• 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
–
• 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
–
• 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.
–
• 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.
–
• 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
–
• 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.
• 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?