Hazards Flashcards
Los Angeles multi hazard area
earthquakes occur all the time due to fault lines, landslides because of typography and the buildings on mountains, flooding, shortage of water supply because its in the desert has to be piped in from far away
nepal earthquake 2015
8.1 earthquake, 8786 dead, 22303 Beverly injured, loss of economy was $7 trillion, because of fear tourism stopped further suffocating economy
indian ocean tsunami 2004
9.1 earthquake caused the seabed to rise 15m for over 1500km, destructive plate boundary, 228000 dead, high population density meant disease spread fast afterwards, $14billion in aid, warning systems put in place
Philippines multi hazard zone
convergent plate boundary, 22 active volcanos, 30% of people live within 30% of a volcano, prone to tsunamis, typhoon belt, high levels of poverty make it vulnerable, 2013 within 3 months 223 dead from earthquake typhoon Haiyan killed 6201 and floods killed 64
hazard
potential threat to human life or property, geophysical, atmospheric, hydrological
hazard perception
people view them differently due to wealth, experience, education, religion and mobility
human responses to hazards
fatalism, prediction, adaptation, mitigation, management, risk sharing
aspects affecting human responses
incidence- frequency of a hazard, distribution- wher the hazard happens, intensity- how strong the hazard is, magnitude- size of hazard usually measured
how does level of development affect responses
lower economically developed areas will have less effective management techniques in place whereas wealthier countries may be able to be more effective, the material in wealthier countries are also more expensive whereas in poorer countries there cheaper and easier to rebuild
the park model
stage 1-level of life before event, stage 2-when event happens but life is still at normal level, stage 3-quality of life drops for hours or days depending on responses, stage 4-relief strategies are underway which makes quality of life improve, stage 5-long term responses making quality of life return to normal
hazard management cycle
preparedness, response, recovery, mitigation
structure of the earth
inner core-solid ball of iron and very hot, outer core-iron/nickel, mantle- solid rocks, asthenosphere-semi-molten layer always moving top and down due to convection currents, lithosphere-broken up into plates and the top layer is the crust, crust- oceanic crust is dense and destroyed by plate movement whereas continental crust is less dense and not destroyed
conservative margin hazards
earthquake
constructive margin landform
volcanoes, earthquakes, ocean ridges, rift valleys
destructive margin landforms
fold mountains, earthquakes, volcanoes, island arcs, ocean trenches
destructive plate margins
heavier plate drops between the other one building up pressure which can lead to volcanoes being created and earthquakes
constructive plate margins
plates move apart from each other allowing magma to come up and fill in the space or rift valleys
conservative plate margin
when plates move in opposite parallel directions or at different speeds the pressure built up can lead to earthquakes occurring
volcanic hotspots
areas of volcanic activity not due to plate boundaries, hot magma plumes from the mantle rise burning the crust causing volcanoes and islands such as Hawaii
volcanic hazards
lava flows, mudflows, tephra- rocks ejected from volcanoes, toxic gasses, acid rain, nuees ardente/pyroclastic flows-clouds of burning hot ash and gas that collapse down volcanoes at speeds of 60mph but can reach 420mph
primary effects of volcanoes
ecosystems damaged, businesses and industries destroyed or disrupted, people and homes destroyed, important government buildings destroyed
secondary effects of volcanoes
jobs lost and lack of tourism, conflicts concerning how to respond to an incident, trauma and homelessness, acid rain polluting water sources, volcanic gasses contributing to the greenhouse effect
prevention of volcanic hazards
volcanoes can be prevented just the risk to the people for example evacuating
preparedness of volcanic hazards
monitoring seismic activities, education of volcanoes, procedures in place
mitigation of volcanic hazards
concrete blocks to steer lava away, strengthening certain buildings at risk, evacuation and exclusion zones, emergency aid and rescue
adaptation for volcanic hazards
move away, encourage tourism to capitalise on the opportunity, change profession so your job isn’t at risk by the volcano
seismic hazards
plates don’t fit perfectly or move perfectly so friction can build up and when this happens convection currents still push which builds up pressure eventually giving way released in a sudden movement
hazards caused by seismic events
shockwaves are smaller weaker vibrations further away from an earthquake, Tsunamis, liquefaction, landslides and avalanches
tsunami
earthquake rocks the floor displacing water pushing it up, oscillations sent off which develop underwater at great speed, seawater is then sucked in and then the waves get bigger as they approach the shore
liquefaction
soil becomes saturated as the vibrations make soil weaker and as water comes in it goes straight through the soil meaning it can’t hold the weight, this happened in Christchurch, New Zealand
primary effects of seismic events
fault lines can be caused which destroy environments, liquefaction, businesses destroyed, buildings collapse, killing or trapping people, government buildings destroyed
secondary effects of seismic events
dangerous materials leaked from power plants, soil salinisation, economic decline, high cost of rebuilding, essential supplies destroyed such as water, gas and electricity, political unrest, boring from other countries, lawlessness
prevention of seismic events
can’t really be prevented but liquefaction can be stopped if soil is stabilised, controlled explosions to stop avalanches
preparedness for seismic events
earthquake prone areas have extensive strategies in place and education, warning systems, evacuation plans
mitigation of seismic hazards
search and rescue emergency teams ready, demolishing unsafe buildings, tsunamis wall
adaptation to seismic events
more away, encourage tourism, insurance, change lifestyle choices, earthquake proof buildings
Armenian 1989 earthquake
6.8 Mw, 20000 people died due to weak buildings
Loma Prieta 1988 earthquake
Along san andreas fault, 63 people died due to wearthquake proof buildings
Japan 2011 earthquake and tsunami
- 9.0
- 10m high waves
- waves were 28m high in a river valley because water was concentrated
