Tectonics EQ1 Flashcards
why are some locations more at risk from tectonic hazards
-live on a plate boundary
-population density
-level of development
-unstable government
-lack of preparation
-low infrastructure quality
-poor AID/ management
-secondary hazards
why do tectonic plates move
-mantle convection
-slab pull
-subduction zone movement
-sea floor spreading
Describe the crust
oceanic 6-10 km thick, continental <70km thick
up to 400°C. Solid state
Describe the mantle
700-2890 km thick.
870°C.
upper part is solid and lower part is semi molten
Describe the outer core
2890-5150 km thick
4400-6100°C
liquid iron and nickle
Describe the inner core
5150-center km thick
7000°C (radioactive decay)
solid
Describe divergent (constructive) plate boundaries (iceland)
two plates that move away from each other. They are most commonly found at mid oceanic ridges which causes sea floor spreading. when the plate separates new oceanic plate is formed because magma rises through the rift valley then hardens to form new crust. At this boundary you get shallow focus earthquakes submarine (under the sea) but these arent very powerful as less friction. Also get shield volcanoes here but they arent very explosive
Describe convergent plate boundaries (oceanic-continental)
plates move towards each other then the denser plate (oceanic) slides below the other (continental). This happens in the subduction zone. here huge friction is generated between the two plate and deep ocean trenches appear. in the subduction zone, the lithosphere then melts and erupts out a composite volcano. Also when the energy.
define the terms “basalt” and “andesite” and explain where they are typically found
basalt and andesite are both types of lava.
Basaltic lava: is typically found at shield volcanoes and ocean hot spots. it is thin and runny as it has a low viscosity and it has a low gas content. it is the hottest type of lava at 1000-1200°C.
Andesitic lava: is typically found at composite volcanoes. It is thicker than basaltic as it has a intermediate viscosity. It is less hot than basaltic lava at 800-1000°C but more explosive
what is a Benioff zone and how does it relate to earthquakes
The Benioff zone is the area of seismic activity in the subduction zone. It is where pressure builds up between plates as they are moving due to friction then it gets released here causing an earthquake.
what is pyroclastic flow
it is a primary hazard of a volcanic eruption. It is a mixture of ash lava and gases that runs quickly down the side of a composite volcano.
what is lava flows
It is a primary hazard of a volcanic eruption. Lava travels down the side of a shield volcano and moves slowly
what is tephra and ash cloud
it is a primary hazard of a volcanic eruption. tephra is fragmented material expelled during an eruption varying is size. Ash cloud is formed when the tephra is expelled and it can travel and surround building
what are gas eruptions
it is a primary hazard of a volcanic eruption. Gases get emitted into the air. This can kill livestock and can be harmful to breath in. It can also cause the secondary hazard of acid rain
what are lahars
It is a secondary hazard of a volcanic eruption. It is when ash and lava combines with water from lakes or rivers causing flooding
what are jokulhlaups
It is a secondary hazard of a volcanic eruption. it is when lava meets a glacier causing it to melt resulting in flooding
how many people died in the 2004 boxing day tsunami
300,000 deaths
what was the cost of damages for the 2004 boxing day tsunami
$5.5 billion
how many people lost jobs in the 2004 boxing day tsunami
2 million
how much was given in aid in the 2004 boxing day tsunami
$700 million
Factors affecting hazard risk for the 2004 boxing day tsunami
-no warning systems / unprepared
-9.0 magnitude
-poor infrastructure
-political insibility
-remote areas
-low level land
-series of waves with large wavelength
-low levels of development
-lack of education
what was the magnitude of the 2004 boxing day tsunami
9.0
what was the magnitude of the 2011 tsunami in japan
9.0
how many people died in the japan 2011 tsunami
16,000
what was the cost of damages for the japan 2011 tsunami
$230 billion
what was the hazard risk for the japan 2011 tsunami
-high population density near costlines
-ageing population
-such high magnitude
-defenses failed
-land subsided
-vunerable infrastructure like a nuclear powerplant on the coast
what are P-waves
“primary waves” are a type of seismic wave generated by earthquakes
What is the difference between a hazard and a disaster
Hazard is the potential threat and disaster is the outcome. Not all hazards turn into disasters
Name some human factors that increase risk of a hazard becoming a disaster
-population density
-government stability
-level of development
-location
-preparedness
-strength of infrastructure
What is vulnerability
The ability to anticipate, cope with, resist and recover from a natural hazard
What is resistance (capacity to cope)
The ability of a community or society exposed to hazards to resist, absorb and recover from the effects of a hazard
Describe the deggs model
Shows that’s when a vulnerable population and a hazardous event overlaps it can result in a disaster
What are the 5 key factors to explain why the relationship between risk hazards and people is so complex
Unpredictability
Lack of alternatives
Dynamic hazards
Cost-benefit of staying put
Russian-Roulette reaction
How does an aging population increase a countries risk
Affects a communities resilience. They may lack education as they have been out of school for so long. Less mobile so slower evacuation. May lack access to internet for alerts. Retired people do less to help economy and can’t afford repairs as much
What does that PAR model stand for
Pressure and release
What is the PAR model
Pressure from people and they’re vulnerability and release is ways to reduce pressure and vulnerability
What magnitude was the Haiti 2010 earthquake
7.0
How many people died in the Haiti 2010 earthquake
300,000
How many schools where damaged or destroyed in the Haiti 2010 earthquake
4000
What was the root causes of vulnerability in the Haiti 2010 earthquake
-heavily in debt to US, German and French banks
-corrupt government
-80% of population below poverty line
What was the dynamic pressures increasing vulnerability in the Haiti 2010 earthquake
Lack of:
Urban planning
Disaster preparedness
Education systems
Disaster management
Also:
Rapid urbanisation
High population density
Deforestation and soil degradation caused landslides
What was the unsafe conditions increasing vulnerability in the Haiti 2010 earthquake
-soft soil
-illegal housing
-low GDP
-poor infrastructure
-lack of access to safe water and sanitation
What city was the 2002 volcanic eruption in the DRC
Nyriagingo
What was the VEI of the eruption in Nyriagongo in 2002
6
What was the speed of onset in the Nyriagongo 2002 eruption
60kph
How many people were killed in the 2002 Nyriagongo eruption
250
How many people were made homeless in the 2002 Nyriagongo eruption
120,000
How many people have to evacuate to neighbouring countries in the Nyriagongo eruption
400,000
what are the social impacts of the Nyriagongo earthquake
deaths
destroy 20% of homes
forced to evacuate
homelessness
drinking acid rain
what are the economic impacts of the Nyriagongo earthquake
loss of income (farming)
2/4 hospitals destroyed
tourism decline
increased poverty
agriculture loss
what was the magnitude of the 2008 Sichuan earthquake
7.9
how many people died in the 2008 Sichuan earthquake
87,000
how many people were displaced in the 2008 Sichuan earthquake
4.8 million
what was the reconstruction costs of the 2008 Sichuan earthquake
$147 million
what was the social impacts of the 2008 Sichuan earthquake
deaths
displacement
schools destroyed
cultural loss- heritage sights
what was the economic impact of the 2008 Sichuan earthquake
infrastructure damage
loss of agriculture
reconstruction costs
migration to urban areas
what was the magnitude of the 2001 japan tsunami
9.0
how many people were killed in the japan 2011 tsunami
20,000
how many people were made homeless after the 2011 japan tsunami
50,000
what was the cost of property damage in the 2011 tsunami
$360 billion
what are the social impacts of the japan 2011 tsunami
deaths
homelessness
psychological trauma
education impact
cultural loss
health issues in temporary shelters
what are the economic impacts of the 2011 japan tsunami
infrastructure damage
property damage
disruption of industry e.g. manufacturing
unemployment
loss of tourism
insurance claims
