52 terms

Geophysical hazards 2019

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Vulnerability
The geographic conditions that increase the susceptibility of a community to a hazard or to the impacts of a hazard event.
Acceptance approach
Those who think the benefits of living in San Francisco outweigh the earthquake risk have this.
Adaptation approach
The new international terminal at Istanbul's Sabiha Gökçen Airport is an example of this.
(Vulnerability) Demographic factor (children)
Sichuan Earthquake, China, 2008
(Vulnerability) Demographic factor (women)
Boxing Day Tsunami, Indonesia, 2004 (40-45 000 more)
(Vulnerability) Demographic factor (large population size and high population density)
Slums in Port-au-Prince, Haiti Earthquake, 2010
(Vulnerability) Community preparedness (lack of building codes)
L'Aquila 2009
A Community's Ability to deal with a Hazard Event (effective lines of communication)
100 000 troops quickly mobilized by the Chinese government and overseas aid allowed into the country (Sichuan, 2008).
Community Preparedness (lack of awareness of hazards)
Chernobyl 1986, Boxing Day Tsunami, 2004
Year of the Boxing Day Tsunami
2004
Year of the L'Aquila Earthquake
2009
Year of the Haiti Earthquake (Port-au-Prince)
2010
Casualties L'Aquila Earthquake 2009
308
Casualties Boxing Day Tsunami
300 000
Fatalities Port-au-Prince, Haiti Earthquake
220 000
(Vulnerability) Community Preparedness (Early Warning Systems)
EEW 緊急地震速報
Geophysical
The term refers to the workings of the earth. This includes movements on the earth's surface (crust) as well as beneath the surface.
Lithosphere
This is the crust and the upper part of the mantle.
Sial (silicon and aluminium)
The continents are made up of the lightest rocks, known together as this.
Sima (silica and magnesia)
The world's ocean beds are made up of this.
Radioactive decay
Convection currents occur in the mantle because of this. Upward movement occurs where the level of this is greatest.
Cinder cone volcano
A steep cone-shaped hill that is made up of layers of ash that have been deposited during successive explosive eruptions.
Composite cone volcanoes (also known as stratovolcanoes)
These form when an eruption spews out combinations of ash, lava, pumice or tephra at various times, which are deposited in layers to form a cone.
Pyroclastic flows
These are very fast moving mixtures of hot blocks of lava, pumice, ash and gases.
Shield volcano (resembles a shield resting on the ground)
Eruptions over hot spots are relatively gentle as lava seeps out to the surface through fissures and vents, adding layer upon layer to previous lava flows.
Four factors can typically trigger a landslide in a volcanic area:
earth tremors caused by magma intruding upwards
an explosive eruption
a significant earthquake
heavy or sustained rainfall
Lahar
A liquid mudflow or debris flow made up of a slurry of pyroclastic materials, rocks and water.
Earthquakes may trigger the following secondary hazards
Landslides
Liquefaction
Tsunamis
Secondary risks associated with tsunamis
Flooding
Being hit by debris
Contamination of drinking water
Fires from ruptured tanks or gas lines
Loss of vital community infrastructure (police, fire, and medical facilities).
Date of the The Indian Ocean Tsunami
26th December 2004
Estimated death toll of The Indian Ocean Tsunami
About 300 000
Number of people who were displaced by the Indian Ocean Tsunami
1.5 million people
Mass movement (or mass wasting)
The downslope movement of weathered rock materials under the influence of gravity.
Four factors that together or separately work to promote mass movement:
slope
water
texture of the weathered material
initial impetus (triggering event)
Mass movement type 1: Slow creep
terracettes
rock creep
talus creep
Four mass movement processes
creep
flow
slides and falls
subsidence
Mass movement type 2: Rapid flowage
earthflows
solifluction
mudflows
debris avalanches
Mass movement type 3: Rockfalls and landslides
landslides
rockfalls
Mass movement type 4: Subsidence
sinkholes
Hazard
Any threat (whether natural or human) that has the potential to cause loss of life, injury, property damage, socio-economic disruption, or environmental degradation.
Hazard event
The occurrence (or realisation) of a hazard, together with the changes in demographic, economic and/or environmental conditions which result.
Geophysical hazard
A hazard that is associated with earth processes, either on the earth's crust or in its sub-structure.
Three methods of measuring earthquake magnitude
Mercali scale
Richter scale
Moment magnitude scale
Method of measuring the intensity of volcanic eruptions
VEI (Volcanic Explosivity Index)
How the risk of landslides can be reduced or minimised
land use planning
relocating people
ensuring that construction standards are met
trying to reduce the level of poverty
Case study of MEDC volcano
Eyjafjallajökull (Iceland), 2010
Case study of LEDC volcano
Soufrière Hills Volcano (Montserrat Island in the Caribbean) 1997-2004.
Case study of MEDC earthquake
L'Aquila (Abruzzo, Italy) 2009
Case study of LEDC earthquake
Port-au-Prince (Haiti) 2010
Case study of a mudslide
Oso (Washington, USA) 2014
Case study of a landslide
Dolina Geyzernov (Russia), 2007
Example of sinkholes
Darvaza, Turkmenistan
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