Disaster hotspot case studies- Califrnia coastline

HideShow resource information
  • Created by: EF98SMRT
  • Created on: 08-03-15 11:14
View mindmap
  • Disaster hotspot case studies- Califrnia coastline
    • Location
      • California is located on the south west coast of North America.
      • 3rd biggest US state with an area of 163,696sqmi and biggest in terms of population with 38,802,500 residents
      • The San Andreas fault (the conservative plate boundary between N. American plate and Pacific Plate) runs through California.
      • Vunerability
        • >70% of the population live within 50km of a fault line.
        • An increasing population has led to buildings being developed on unstable land. This leads to liquefaction during EQs and can also increase the risk of landslides
        • The coast is very developed meaning many people are at risk from Tsnamis
        • 20% of residents live below the poverty line. These people have the lowest capacity to cope with disaster
        • California is a highly developed area with state of the art technology that predicts disasters (e.g seismographs) as well as prevent them (e.g. building reinforcement, disaster training)
          • It has a massive economy which means, combined with it's advanced prevention measures, that losses are mainly economic rather than human
    • Earthquakes
      • The San Andreas fault is a conservative plate boundary which runs through California making it very earthquake prone
        • EQs occur when the parallel plates snag creating a build up of pressure which is suddenly released sending seismic waves in all directions.
          • These EQs are usually shallow in California making them more destructive
      • Facts
        • These is a high chance that a 7.0+ magnitude EQ will hit San Francisco bay in the next 25 years
        • 15-20 4.0+ magnitude EQs each year.
        • More than 70% of California's population live within 50km of a fault line
        • California has lots of building on unstable land which causes severe liquefaction
      • Loma Prieta EQ- 1989
        • A magnitude 7.1 struck in the Santa Cruz mountains 60 miles south of San Fransisco at 5:04 pm on 17 October 1989
          • A magnitude 5.2 aftershock struck 37 mins after the main EQ
        • 63 people were killed (mainly by a collapsed freeway); 13 750 were injured; 1081 homes were destroyed; 23 408 homes were damaged; just under 4000 businesses were destroyed or damaged; total cost US$6 billion
          • The death toll was low due to the freeways being unusually clear due to the world series baseball game
      • Northridge EQ Los Angeles- 1994
        • 57 killed; 1500 injured; 12 500 buildings damaged; 9000 homes and businesses without electricity; 20 000 without gas; 48 500 without water; damage to several freeways
        • A magnitude 6.7 Eq struck the densely populated San Fernando VAlley at 4:31 on 17 Jan 1994
          • 1000s of after =shocks of magnitude 4.0-5.0 occurred in the following weeks
    • Volcanoes
      • The last major volcanic activity was in 1915 when Lassen Peak erupted.
      • Despite this many volcanoes are being monitored for activity such as Lassen Peak, Mount Shasta etc
    • Tsnamis
      • Caused by an EQ under the Pacific Ocean, a tsunami could devastate the many cities on the coast such as LA and San Francisco
      • Crescent City Tsunami 1964
        • On 28 March 1964 an underwater EQ of the coast of Alaska generated a tsunami which affected the entire Californian coastline. Crescent city was the worst affected with waves of up to 20ft.
        • 11 people killed; $7,414,000 worth of damage; a further $1,500,000 along the rest of the Californian coast; fires broke out due to overturned gas truck;
    • Droughts
      • They occur during La Nina years in which the waters of the Eastern Pacific are cooler
        • This results in less evaporation of surface water so less rainfall
      • They are also caused by anticyclones (long lasting spells of high air pressure and sinking dry air)
      • Also caused by an increase in dry, desert winds blowing form the east.
      • Puts pressure on densely populated areas such as LA where there is a shortage of water.
      • Wildfires
        • Wildfires are one of the most dangerous effects of drought periods.
        • Southern California wildfires 2007
          • 14 people killed; 160 injured; 1,500 homes destroted; 3,900sqkm of land burned; approx. 1,000,000 people evacuated. There were also concerns about the effect of particulates on health
          • Causes
            • Dorught, hot weather and strong Santa Ana
            • Sources include: damaged power lines, an over turned truck and even arsonists.
          • A series of wildfires beginning 20th October 2007 swept across southern California. The fires were visible from  space
            • 17 of the fires were classified as major fire incidents
        • As cities such as LA and San Francisco expand or people relocate into the hills fires become more hazardous to the population with more potential for damage.
    • Landslides
      • They are often caused by EQs during which sediment is shaken lose.
        • The effect of this is magnified by wildfires which destroy plants that bind soil.
        • Winter storms also erode soil causing landslides.
          • Coastal erosion may also be a cause of landslides along the coast. Coastal climates are becoming more unpredictable increasing the risk of landslides
      • The risk of landslide disaster is increased by building on steep, unstable land.
      • La Conchita landslide 2005
        • On the 10th Jan 2005 a major landslide (200,000 cubic meters) occurred in La Conchita on the site of a previous landslide (1995)
        • 10 people were killed; 13 houses destroyed; 23 damaged
        • The owners of the La Conchita Ranch (located at the top of the slope) were held partially accountable due to their inadequate drainage systems

Comments

No comments have yet been made

Similar Geography resources:

See all Geography resources »See all Natural hazards resources »