1.4 Flashcards
What affects an earthquakes severity?
Magnitude - energy
Distance from the epicentre/focus
Bedrock + soil
What is a method to test if there is a correlation between deaths/injuries and magnitude of a quake?
To use spearman rank formula:
Rs = 1 - (6Ed^2)/n(n^2-1)
E = the total of Rs = overall value of Rank D = difference N = number of values/sites
What is an example of a developed nation that had an earthquake?
Christchurch , New Zealand in 2011 had a 6.2 magnitude earthquake that was caused by a release of tectonic strain along the conservative margin.
What were the primary hazards of the Christchurch earthquake?
1) 185 deaths - buildings collapsing and catching fire
2) 3129 people injured
3) April 2013 total estimated costs $40 billion
4) Liquefaction in eastern suburbs produced 400,000 tonnes of silt
5) Damage to buildings as 100,000 buildings were damaged and 10,000 were demolished
6) phone lines and communication was shut off
What were the secondary impacts of the Christchurch earthquake?
3.5m tsunami in Tasman lake causing Tasman glacier to trigger
Water pipes and bridges and roads were damaged
80% of Systems of sewerage and water was severely destroyed
80% of residents said psychological factors had impacted the,
Divorce rates increased from 211 to 249
Population declined for the first time in a long time
Christchurch couldn’t host the rugby World Cup so they lost tourism
What made the Christchurch earthquake impacts worse?
1) Epicentre was close to Christchurch
2) Focus was shallow only 5km underground
3) occurred during a lunchtime in the CBD, meaning it was busy and buildings were still damaged by the previous quakes
4) seismic waves were very strong (L waves)
5) liquefaction was significantly greater then the 2010 quake, undermining lots of infrastructure.
What were the responses to the quake from people in New Zealand?
Rescue crews were dispatched from across the globe
Australia gave $5 Million in aid
Government declared it a national emergency
The area was split into 4 zones : green, orange, white and red
Green allowed building , red was very unsafe ground
Charities helped eg save the children
What are some facts about the New Zealand earthquake?
The largest aftershock was 2 hours after 5.9
Aftershocks were recorded after a month the earthquake happened
This was created as the pacific plate slid past the Australian plate at the boundary causing horizontal movement with a slight vertical uplift.
Was there any warning systems in place for Christchurch?
New Zealand has a history of being very tectonically active so quakes were common therefore, people had some knowledge that a big earthquake could happen
Scientists didn’t know that the fault existed so it was hard to predict.
What is an example of a developing nation that was hit by a powerful earthquake?
The Haiti earthquake in 2010 and the Dominican Republic
What are some facts about the Haiti earthquake in 2010?
It was a large scale earthquake on the 12 January 2010
It occupied 1/3 of the island
Displaced many people across islands
Was 25km south west of the capital Port-au-prince
Was many aftershocks
Was caused by an undiscovered fault - Leogane fault
Was a shallow focus
What were primary impacts of the quake in Haiti?
Around 300,000 deaths but that varies
- influential figures in the UN were killed
Buildings were destroyed many residences
80% of schools and 60% of hospitals destroyed
Left many people homeless and homes destroyed
Disrupted transport systems
What were secondary impacts of the quake in Haiti?
2 Million people affected 1100 temporary camps Outbreaks of cholera killed many Storms and flood soon after quake Damage of $11.5 billion
What were responses to the Haiti earthquake?
Search and rescue teams were immediate Sensitive equipment was used - flown in Aid was sent in from utilities UK gave £100 Million used for sanitation mainly 3/4 of houses were repaired Caused out-migration from port-au-prince World bank gave £100 Million
How was the damage in Haiti influenced by factors?
It is a LEDC
Has limited supply of resources
No regulations to secure what happened after an earthquake
Housing were cheap and poor quality
Was Haiti prepared for the quake?
No, as they are they are one of the poorest countries in the world. This was amplified by the US taking taxes and kidnapping the presidents
What classification were the hazards?
Hazard - Christchurch New Zealand
Mega-disaster Haiti
What were the wave types in the New Zealand earthquake?
P and S waves
What are some facts about New Zealand earthquake?
A September 2010 earthquake centered 40 kilometers (25 miles) west of Christchurch, in the plains near Darfield, struck at 4:35 a.m., had a magnitude of 7.1, and caused some structural damage and one death (by heart attack). The earthquake in February 2011 occurred at 12:51 p.m. and just 10 kilometers (6 miles) from the center of Christchurch. It had a magnitude of 6.3, though was officially classified—scientifically speaking—as an aftershock of the 2010 quake. At least 166 people died, and the city of Christchurch was devastated structurally and emotionally. Many people are still missing.
What are facts about Haiti
7.0 Magnitude Quake struck near Port au Prince
3,500,000 people were affected by the quake
220,000 people estimated to have died
300,000+ people were injured
Over 188,383 houses were badly damaged and 105,000 were destroyed by the earthquake (293,383 in total), 1.5m people became homeless
After the quake there were 19 million cubic metres of rubble and debris in Port au Prince – enough to fill a line of shipping containers stretching end to end from London to Beirut.
4,000 schools were damaged or destroyed
25% of civil servants in Port au Prince died
60% of Government and administrative buildings, 80% of schools in Port-au-Prince and 60% of schools in the South and West Departments were destroyed or damaged
Over 600,000 people left their home area in Port-au-Prince and mostly stayed with host families
At its peak, one and a half million people were living in camps including over 100,000 at critical risk from storms and flooding
Unrelated to the earthquake but causing aid response challenges was the outbreak of cholera in October 2010. By July 2011 5,899 had died as a result of the outbreak, and 216,000 were infected
When does a natural process become a hazard?
When people are affected
When does a hazard become a disaster?
When affects a vulnerable population
500 deaths
When do disasters becomes mega-disasters?
when over 2000 die or 200,000 are made homeless or 5% reduction in the countries GDP or dependence on aid for over 1 year.
What is Dregg’s Model?
It is a model to show that there are two factors:
1) the size of the hazard
2) the vulnerability of the population
What makes a population vulnerable?
Topography, geology, development level, economic and social status, government and political corruptness, magnitude severity
What are 2 examples of a mega-disaster?
Haiti 2010
Indian Heatwave in 2015
How can risk be predicted?
it can be predicted by using the hazard risk equation and analysed with the PAR model.
What is the equation for risk reduction?
Mitigation of hazard x reduction of vulnerability and increasing capacity to cope
What is vulnerability?
how susceptible a population is to impacts of a hazard.
What is a risk or damage threshold?
how far a hazard can be classified as a hazard until its a disaster
Why is the reduction of vulnerability is hard to do?
the energy of tectonics are hard to manage and way beyond modern day technologies.
How can vulnerability be reduced?
estimating energy
monotoring tectonic areas
better governance
improve mitigation methods
What is the PAR model?
Pressure and model which, combines the vulnerability of an area and all the factors along with the hazard making a disaster.
What are root causes in the PAR model?
basic threats eg Limited access to… and ideologies from higher powers
What are dynamic pressures in the PAR model?
Things the country lacks or larger forces that are hard to control eg Training or population growth
What are unsafe conditions in the PAR model?
Physical factors that amplify or help the quake eg Fragile-physical environment, local economy, vulnerable society and public actions eg diseases
