Tectonics EQ2 Flashcards
What does Degg’s model show?
the intersection between a hazardous natural event, such as an earthquake, hurricane or landslide and a vulnerable population which experiences human and/or economic loss, to create a disaster.
what is meant by a ‘ threshold ‘ level ?
the extent to which a community is able to deal with a disaster & whether the event is large enough to be considered a disaster or a hazard.
e.g after :10 or more deaths, 100 or more people affected, US $1 million in economic losses
what is the hazard risk equation ?
Risk = hazard x vulnerability / capacity to cope
outline 3 of each factor affecting risk from a natural hazard :
governance & political conditions
economic and social conditions
physical and environmental conditions
G&PC
- efficiency of emergency services & response teams
- existence of public education and practise of hazard response
- extent of corruption of businesses and gov officials
E&SC
- level of wealth affecting peoples ability to protect themselves
- access to education
- quality of housing
P&EC
- population density
- speed of urbanisation
- accessibility of an area
define resilience
the ability of a community to cope with a hazard
some communities are better prepared than others so a hazard is less likely to become a disaster
also includes the ability to return to normal following a disaster.
how does age affect resilience to a natural hazard ?
children and old people suffer more.
Around 66% of those over 60 live in less-developed regions, expected to rise to 79% by 2050.
why do some communities have a higher capacity to cope then others ?
they have emergency evacuation, rescue and relief systems in place
they react by helping each other, to reduce numbers affected
hazard-resistant design or land-use planning have reduced the numbers at risk
For these communities the threshold for disaster will be higher than for ones with low coping capacity.
what is the use of the PAR model ?
used to understand a countries vulnerability to hazards
- it assume that disasters happen when opposing factors interact
- suggests socio - economic context of a hazard is important
- looks at 3 main factors, along with the hazard itself
1. ROOT CAUSES
- political and economic systems that control who has power over resources
e.g 80% of Haitians living below poverty line, heavily in debt country
2. DYNAMIC PRESSURES
- lead to unsafe conditions
e.g no disaster preparedness in Hati, people didn’t know how to respond
3. UNSAFE CONDITIONS
e.g poor living conditions & infrastructure = more damage
why is comparing tectonic hazards hard ?
because both the physical nature of the event and the socio-economic profiles of affected places are different. Some general observations are:
1. economic costs in developed and emerging economies are, in some cases, enormous
2. deaths in developed countries are low, except for the 2011 Japanese tsunami (a very rare mega disaster)
3. volcanic eruption impacts are small compared with those of earthquakes and tsunami
how are volcanic explosions measured ?
VOLCANIC EXPLOSIVITY INDEX (VEI)
- measure magnitude
- logarithmic scale
0 = non - explosive
8 = extremely large
what is the VEI based on ?
volume of tephra & ash & pyroclastic flows etc
height of material ejected
duration of eruption
observations e.g gentle eruption
what is the magnitude of earthquakes measured ?
MOMENT MAGNITUDE SCALE
- measures larger earthquakes
- measures energy ( magnitude ) by looking at info on seismic waves, rock movement etc
- scale from 1 - infinity ( largest recorded earthquake was 9.5
- logarithmic
how is earthquake intensity measured ?
MODIFIED MERCALLI INTESNITY SCALE ( MMIS )
- scale of ‘I’ = hardly noticed to ‘XII’ - catastrophic
what are hazard profiles ?
a way of showing characteristics of hazards
- help show how different hazards can be compared
- help gov & NGO’s to develop disaster plans
- look at afctors such as onset, frequency and magnitude )
why has the number of reported hazards risen since 1960 ?
- better monitoring & reporting
e.g in 2011, the tsunami that followed the sendai earthquake was shown on TV - increased pop density near rivers & coasts = more awareness of storm & flood events
