what 4 things must the definition of a natural disaster include
- 10 reported killed
- 100 reported affected
- declared a state emergency
- call for international assistance
how is the magnitude and intensity of tectonic hazards measured
mercalli scale
moment magnitude scale
volcanic explosivity index
what is the moment magnitude scale
the mms goes from 1 to 10 with a higher number meaning a greater magnitude. the scale is also logarithmic meaning that an increase of 1 unit of magnitude increases the amount of shaking by 10 and the amount of energy released by 30
what does the moment magnitude scale measure
the amount of energy released by a tectonic hazard (version of richter scale)
what does the mercalli scale measure
the damaging effects of earthquakes by measuring the intensity of shaking on a scale of 1 to 12 (usually given as roman numerals)
what is the volcanic explosivity index
the vei is based on the volume, duration, and column height of the volcano. the explosivity is related to the type of magma and the type of plate boundary that the volcano is located on
what does the volcanic explosivity index measure (vei)
it measures the volcanic magnitude
give examples of low and high vei
low = 0-3 (constructive)
high = 4-7 (destructive)
explain the PAR model
the model says that the risk is a function of vulnerability and the nature of the hazard. The socioeconomic context includes the political system, income levels, economic strength, levels of education, population change and investment.
what does the PAR (pressure and release) model look at
root causes
dynamic pressures
unsafe conditions
what do the PAR root causes include
limited access to power
limited access to resources
poor buildings and foundations
corruption
weak economic system
what do the PAR dynamic pressures include
lack of training
lack of investment
press freedom
rapid population change
rapid urbanisation
deforestation
what do the PAR unsafe conditions include
physical environment
local economy
social relations
public action
