California Hotspot
- Created by: keeels
- Created on: 07-05-14 21:25
View mindmap
- California
- The state of California in the USA has many highly populated towns and cities at risk from a variety of hazards.
- Earthquakes
- The San Andreas fault runs the length of California- it's a conservative plate boundary
- Earthquakes occur when pressure between the plates builds up and then is suddenly released as they jerk past each other
- Califronia has two or three earthquakes each year that are powerful enough to damage structures (5.5+ on the Richter scale)
- Studies of the frequency and magnitude of past earthquakes show that there's a good chance of an earthquake of magnitude 7.0+ hitting the San Francisco Bay area before 2025
- Past disasters include the San Francisco earthquake of 1906 (thought to have measured 7.8) which along with subsequent fires, destroyed much of the city
- Droughts
- Drought in California can be caused by anticyclones (long lasting periods of high air pressure with sinking, dry air) Dry, sinking air means no rain.
- Drought can also be caused by La Nina events (periods when the surface water in the eastern Pacific Ocean is cooler). This means less evaporation, so there's less precipitation
- Another cause of drought is increased wind blowing westward from the desert areas that are east of California, e.g from Arizona. The dry air has no moisture to cause precipitation
- The most devastating effect of drought in California is wildfires - dry vegetation is extremely flammable, so fires spread quickly over wide areas
- The wildfires in southern California in October 2007 killed 22 people and destroyed 1300 homes
- Tsunamis
- A tsunami is a series of large waves that can flood coastal areas
- They can be caused by earthquakes on the sea bed, or landslides into the sea
- Earthquakes under the Pacific Ocean could cause a tsunami along the California coastline
- An earthquake off the coast of Alaska in 1964 caused a tsunami to strike the coast of northern California, killing 12 people in Crescent City
- Landslides
- Landslides occur on unstable steep land. Land can be made unstable by coastal erosion or extreme weather (rainstorms). Landslides can be triggered by earthquakes
- The risk of landslide disaster in Califronia is high because of building on and around steep slopes, as well as building on coastal land overlooking the ocean e.g La Conchita
- Volcanoes
- There hasn't been a volcanic eruption in California since 1915 (Lassen Peak)
- But there are volcanoes being monitored for potential eruptions, e.g Lassen Peak, Mount Shasta and the Volcanoes around Mammoth Lakes
- Vulnerable Population
- More than 70% of California's population live within 50km of a fault line
- There's a lot of building on unstable land - this can lead to soil liquefaction during earthquakes (where the ground can become more like a liquid), which damages buildings and increases the risk of landslides. This was a major problem during the Loma Prieta earthquake in 1989
- There are many buildings along the coast that are vulnerable to tsunamis
- California is a wealthy state, but there are very poor areas within it - around 20% of the residents in Los Angeles live below the official poverty line. These people have the lowest capacity to cope when affected by a hazard
- Califronia has a massive economy, so there are likely to be huge economic losses when a disaster occurs
Similar Geography resources:
Teacher recommended
Comments
No comments have yet been made