Theme 3 - Vulnerabilty and hazard reduction Flashcards
Volcanic explosivity index?
a measure of the explosiveness of volcanic eruptions on a scale of 1-8.
Magnitude?
a quantitative measure of the size of an earthquake using the Richter scale.
Richter scale?
a measure of the magnitude of an earthquake on a scale of 1-10.
Lava flow?
a stream of lava flowing from a volcanic vent.
Ash cloud?
a large cloud of smoke and debris that forms over a volcano after it erupts.
Pyroclastic flow?
the cloud of gas, ash, dust, stones and rocks emitted during a highly explosive volcanic eruption.
Lahar?
mudflow associated with volcanic activity.
Liquefaction?
occurs when vibrations cause soil particles to lose contact with one another, as a result soil behaves like a liquid and can flow down very gentle slopes.
Tsunami?
a long, high sea wave caused by an earthquake or other disturbance.
What are 4 physical factors that increase vulnerability to earthquakes?
.ground movement and shaking
.soil liquefaction
.landslides
.tsunamis
How vulnerable to tectonic activity a region is depends on: ? (4)
.magnitude
.duration
.predictability
.regularity
Vulnerability?
the potential to be harmed by a natural hazard.
Aftershocks?
ground tremors occuring after a major earthquake but associated with the same focus.
Capacity?
the ability of a country or region to react to and recover from a natural hazard.
Focus?
the source of a shockwave, which can be at varying depths.
Epicentre?
the point on the earth’s surface immediately above the focus.
What are social and economic human factors that increase vulnerability? (7)
.wealth
.education
.goverments
.age
.health
.population
.time of day
.emergency services
Seismometer/seismograph?
an instrument used to detect and record earthquakes.
Hazard map?
a map that highlights areas affected by or vulnerable to a particular hazard.
Risk?
the probability of a hazard event causing a harmful consequences.
What are some earthquake monitoring techniques? (3)
.laser beams - detect plate movement
.seismometer/seismograph - detect vibrations in earth’s crust
.levels of radon gas escaping from cracks in the earth’s crust
What are some volcanic eruption monitoring techniques? (4)
.remote sensing - satellites monitor gas emissions and use thermal imaging
.visual signs - cameras are used to look for visual signs of change in the volcano
.seisometers - measure earthquake activty that may lead to an eruption of a volcano
.gas emissions - these increase before an eruption
How are hazard maps useful to local authorities? (2)
.limit access to hazardous areas
.control development in areas at risk from tectonic events
Emergency planning (7)
.exclusion zones set up near a volcano
.evacuation routes
.lava flows can be diverted
.emergency services trained to handle disasters
.people can be educated through TV, social media, and school
.people may put together emergency kits to store at home
.roads and bridges can be designed to withstand the power of earthquakes
