D.2 Geophysical hazards risks Flashcards
How are earthquakes generally distrobuted?
Most of the worlds earthquakes occur in clearly defined linear patters, these linear chains genrally follow plate boundaires.
where are broad belts of earthquakes found?
they are associated with subduction zones
where are narrow belts of earthquakes found?
they are associated with constructive (same as divergant) plate plate margins
there are a few isolated occurrences of earthquakes (not where you would expect them to be), why might this happen?
due to human activities or to isolated pumps of rising magma known as hotspots.
where do volcanos occur?
Some volcanoes, like those that form the Hawaiian Islands, occur in the interior of plates at areas called hot spots. Although most of the active volcanoes we see on land occur where plates collide, the greatest number of the Earth’s volcanoes are hidden from view, occurring on the ocean floor along spreading ridges.
where do landslides occur?
in every environment on the earth, including the tropics, temperate regions, the high latitudes and also the ocean.
where are places where landslides are more likely to occur?
places with:
1) active tectonic processes that lead to high rates of uplift and occasional seismic events.
2) high levels of precipitation, including both high annual totals and high short-term intensities.
3) a high population density.
what are some LIC that where landslies occur often due to a lack of mitigation?
Southwest India and central China.
what is the recurrence interval/ return period?
it is the expected frequancy of occurrence in years for an event of a particular size.
what is the pattern of recurrence interval?
small events have a very high frequency/ short return period. Large events have a low frequency/ high return period.
Thus there are fewer highly destructive earthquakes but may minor ones.
which type of event will have the greatest destruction and hence need the greatest management.
low frequency/ high return period.
what scale do we use to measure earthquakes?
Moment Magnitude scale (M)
what do we use to measure the strenth of a volcano?
Volcanic explosive index (VEI)
what is vunrabliluty ?
The conditions which increase the susceptibility of an individual, a community, assets or systems to the impacts of hazards.
can you explain how economic factors can increase the risk for people facing a geophysical hazard?
levels of development and technology (forecasts and communication) -
housing, car ownership, insurance,
can you explain how social factors can increase the risk for people facing a geophysical hazard?
Better education = more money, and a greater understanding of what is happening.
Gender-women have to care for their children and parents, may feel responsible for them during an event. Women are at a greater risk than males, as gender inequalities are exacerbated during natural disasters.
(For example, for every man who died in the Indian Ocean tsunami in 2004, four women died). They were not taught how to swim.
In some societies, women may not be allowed to leave an area even if they want to.
what are some demographics that can cause a geophysical hazard risk?
population density and structure
large number of people are harder to evacuate. Both types of dependent populations.
disability.
trust in government and scientists.
what are the political factors that can cause a geophysical hazard risk?
international Relations:
Geophysical hazards can transcend political boundaries, making international cooperation important. Diplomatic relations and agreements between countries can affect the sharing of information, resources, and assistance during and after disasters.
Corruption and Governance:
Corruption within governments can lead to inadequate enforcement of building codes, misallocation of resources, and poor disaster management. Strong governance and anti-corruption efforts are essential to reducing risk.
Trust in goverment and scientists.
what are the geographical factors affecting geophysical hazard event impacts?
rural/urban location.
time of day
degree of isolation.
