Tectonic case studies Flashcards
What percentage of people will experience risk from a volcanic eruption?
Less than 1% of the world’s population
What percentage of people will experience risk from an earthquake?
5%- when you add secondary impacts of earthquakes, this figure rises
What are two examples of mega-disasters?
2010 Eyjafjallajokull Iceland eruption
2011 Tohoku Japanese tsunami
Where are two disaster hotspots?
The Philippines
The California coast
When did the Tohoku earthquake occur?
March 11th, 2011
What magnitude was the Tohoku earthquake?
9.0
Where did the Tohoku earthquake occur?
250 miles off of the North East coast of Japan’s main island (Honshu)
What were the reasons for the Tohoku earthquake and tsunami?
- Japan is located on the Eastern edge of the Eurasian plate, which is subducted by the Pacific plate- a destructive plate margin
- Earthquake occurred at a relatively shallow depth of 20 miles below the surface, when, combined with the high magnitude caused an earthquake
How many people died or were injured as a primary impact of the Tohoku earthquake?
Around 15,000 people died
Over 26,000 were injured
Over 2000 people remain missing
How many people were displaced by the primary impacts of the Tohoku earthquake?
130,000 people
What primary damage was caused by the Tohoku earthquake?
- Buildings, roads, bridges and railways were damaged or destroyed
- 300 hospitals were damaged and 11 destroyed
- Over 4 million households were left without electricity in North-East Japan
What were the primary environmental impacts of the Tohoku earthquake?
- Some coastal areas experienced land subsidence as the earthquake dropped the beachfront in some place by more than 50cm.
- The Pacific plate slipped westwards by between 20-40m
- Liquefaction occurred in many parts of Tokyo built on reclaimed land
What were the secondary effects of the Tohoku earthquake?
- Tsunami waves up to 40m devestated coastal areas and resulted in the loss of thousands of lives, also causing a lot of damage and pollution
- Seven reactors at the Fukushima nuclear power station experienced a meltdown
- Rural areas remained isolated for a long time due to transport disruption
What were the immediate responses to the Tohoku earthquake?
- Japan Meteorological Agency issued tsunami warnings 3 minutes after earthquakes occurred.
- Research workers and around 100,000 members of the Japan self-defence force were dispatched to help with search and rescue
- The government declared a 20km evacuation zone around Fukushima
- Those in the Fukushima area had their health monitored and were given iodine tablets to reduce the risk of radiation poisoning.
What were the long-term responses to the Tohoku earthquake?
- Coastal protection policy introduced, such as seawalls and breakwaters
- Rebuilding of infrastructure and improvement of economy’s health
- Tohoku Expressway and Sendai Airport were rebuilt
- Energy, water supply and landline network were restored
What was the cost of the Tohoku earthquake?
Most expensive natural disaster in history- costing US $235 billion
Describe California:
- Population of 39 million
- Located in Western United States
- Wealth of $4.1 trillion
What are the geophysical hazards present in California?
The San Andreas Fault
What is the San Andreas Fault?
- A fracture within the crust of the earth, which forms the boundary between the Pacific and the North American plate
- The fault is characterised by the movement of rock on either side
- This makes the region prone to frequent seismic activity
What Californian cities lie close to the San Andreas fault?
San Francisco
Los Angeles
San Diego
What natural hazards is California exposed to?
Earthquakes
Soil liquefaction
Landslides
What two earthquakes happened in California?
Loma Prieta- San Francisco
Northridge- Los Angeles
When did the Loma Prieta earthquake happen?
October 17th, 1989
What was the magnitude and location of the Loma Prieta earthquake?
Santa Cruz mountains
6.9 magnitude
How many deaths were caused by the Loma Prieta earthquake?
63 deaths
3757 injuries
What damage was caused by the Loma Prieta earthquake?
$6 billion in property damage
Severe damage in San Francisco and Oakland
Bay Area transport system significantly damaged
When did the Northridge earthquake occur?
January 17th, 1994
What was the magnitude and location of the Northridge earthquake?
San Fernando valley
6.7 magnitude
What were the aftershocks of the Northridge earthquake?
- 3000 aftershocks greater than 1.5 magnitude
How many deaths were caused by the Northridge earthquake?
57 deaths
More than 9000 injured
What damage was caused by the Northridge earthquake?
Property damage estimated to be $13-50 billion
Damage occurred up to 85 miles away
How does California prepare and manage the impacts of its earthquakes?
Earthquake drills
Established methods for alerting public
Steel frames for buildings
California Earthquake Authority is an organisation that provides residential earthquake insurance
Where is the Philippines?
- An island country in Southeast Asia in the western Pacific Ocean
Describe the Philippines:
- Population of 117.3 million
- $1.392 trillion of wealth
What geophysical hazards are there in the Philippines?
- The Philippines lies on the plate boundary between the Philippine and Eurasian plate
- It’s location on the Pacific Ring of Fire and close to the equator makes the Philippines prone to tectonic hazards and typhoons
What are some well-known cities in the Philippines?
Quezon City
Manila
Davao City
What natural hazards are the Philippines at risk of?
Earthquakes
- Landslides
- Tsunamis
Drought
Volcanic eruptions
Typhoons
- Flooding
- Storm surges
What two tectonic events occured in the Philippines?
Mount Pinatubo eruption
Bohol earthquake
When did Mount Pinatubo erupt?
June 12th, 1991
What was the magnitude and location of the Mt. Pinatubo eruption?
- Ranked 6 on VEI
- Zambales mountains
How many deaths were caused by the Mt. Pinatubo eruption?
847 people killed
Around 200 injured
What damage was caused by the Mt. Pinatubo eruption?
More than 8000 houses destroyed
Reforestation projects destroyed
Agriculture and services heavily disrupted
What economic loss did the Mt. Pinatubo eruption result in?
$700 million in damage
When did the Bohol earthquake occur?
October 15th, 2013
What was the magnitude and location of the Bohol earthquake?
- 7.2 magnitude
- Occurred on the island province Bohol
What were the aftershocks of the Bohol earthquake?
- Aftershocks continued for several months
How many deaths were caused by the Bohol earthquake?
222 people died
976 injured
What damage was caused by the Bohol earthquake?
- over 79,000 structures were damaged
- Government and school buildings damaged or destroyed
What magnitude was the Haiti earthquake?
7.0
When and where did the Haiti earthquake occur?
- Occurred on January 12th 2010
- The epicentre was near the town of Léogane, 25km away from Port-au-Prince
Why did the Haiti earthquake occur?
- Haiti is situated at the Northern end of the Caribbean Plate, on a transform / conservative plate boundary with the North American plate
How many people were impacted by the primary impacts of the Haiti earthquake?
- An estimated 3million people were affected
- Over 200,000 people died
- An estimated 300,000 were injured
- An estimated 1million were made homeless
What primary damage was caused by the Haiti earthquake?
- 250,000 residences and 30,000 commercial buildings had collapsed or were severely damaged
What were the secondary effects of the Haiti earthquake?
- 2 million people were left without water and food
- Regular power cuts occurred
- Crime increased- looting became a problem and sexual violence escalated
- People moved into temporary shelters
- By November 2010, there were outbreaks of cholera
What were the immediate responses to the Haiti earthquake?
- Due to the port being damaged, aid was slow to arrive
- The USA sent rescue teams and 10,000 troops
- Bottled water and purification tablets were provided
- 235,000 people were moved away from Port-au-Prince to less-damaged cities
- £20 million was donated by the UK government
What were the long-term responses to the Haiti earthquake?
- As one of the poorest countries on Earth, Haiti relied on overseas aid
- Although the response was slow, new homes were built to a higher standard. Over 1 million people still lived in temporary shelters one year after the earthquake
- The port needed rebuilding, which required a large amount of investment
Why was the Haiti earthquake so damaging?
- It occurred at a shallow depth
- The earthquake struck the most densely populated area of the country
- Haiti is the poorest country in the Western Hemisphere
- The buildings in Port-au-Prince and other areas of Haiti were generally in poor condition and weren’t designed or constructed to be earthquake-resistant
- Haiti only has one airport with one runway, which was severely damaged in the earthquake
- Aid piled up at the airport due to a lack of trucks and people to distribute it
- Rescue teams took up to 48 hours to arrive due to the problems at the airport
- There was a severe shortage of doctors, and many people died of injuries like broken limbs
When and where did the Christchurch earthquake occur?
- Occurred on New Zealand’s South Island, 10km West of Christchurch
- On the 22nd February 2011
What magnitude was the Christchurch earthquake?
6.3
What caused the Christchurch earthquake?
- Conservative margin between the Pacific Plate and the Australasian plate
How many people were affected by the Christchurch earthquake?
- 185 people were killed
- Over 3000 were injured
- Over 2000 had to live in temporary housing
What damage was caused by the Christchurch earthquake?
- Christchurch, New Zealand’s second-largest city, experienced extensive damage
- 100,000 properties were damaged, and 10,000 were demolished
- $28 billion of damage was caused
- Water and sewage pipes were damaged
- Liquefaction destroyed many roads and buildings
What were the secondary effects of the New Zealand earthquake?
- Five Rugby World cup matches were cancelled
- Schools were closed for 2 weeks
- 1/5 of the population migrated from the city
- Many businesses were closed for a long time
- Two large aftershocks struck Christchurch less than four months after the city was devestated
What were the immediate responses to the Christchurch earthquake?
- Around $6-7 million of international aid was provided
- The Red Cross and other charities supplied aid workers
- Rescue crews from all over the world, including the UK, USA, Taiwan and Australia provided support
- 30,000 residents were provided with chemical toilets
What were the long term responses to the Christchurch earthquake?
- The construction of around 10,000 affordable homes
- Water and sewage were restored by August 2011
- The New Zealand government provided temporary housing
- Many NGOs provided support, including Save the Children
When and where did the Sichuan earthquake occur?
- Sichuan province, China
- Occurred on the 12th May, 2008
Why did the Sichuan earthquake occur?
- The pressure resulting from the Indian plate colliding with the Eurasian was sent along the Longmenshan fault line that runs through Sichuan
What magnitude was the Sichuan earthquake?
7.9
Describe the Sichuan region?
- The area is more rural (but still has a population of 43 million people), and is less developed than the highly prosperous areas located along China’s Eastern coastline
How many people were impacted by the Sichuan earthquake?
- The death toll was stated at 69,000
- Between 5-11 million people were made homeless
- About 374,000 people were injured
- In Jujiangyan, 900 students were killed when a school collapsed
- In Shifang, chemical plants collapsed, killing hundreds and spilling toxic ammonia
What damage was caused by the Sichuan earthquake?
- In rural areas near the epicentre, such as beichuan county, 80% of buildings collapsed
- The Wenchuan county at the epicentre was cut off by landslides
- In Shifang, chemical plants collapsed
- In Chengdu, power and water supplies were cut
- About 5 million buildings collapsed
What were the immediate responses to the Sichuan earthquake?
- Troops parachuted into Wenchuan, and hiked on foot, as landslides had made roads inaccessible
- The production of tents was increases, to house people made homeless by the earthquake. Areas of land were flattened so they could be erected
- More than £100 million was donated to the Red Cross in the fortnight after, which went into running camps, and ensuring that food, medicine, doctors, and volunteers were available
- 20 helicopters were assigned to rescue and relief efforts in Wenchuan
- Army troops were drafted in to help with freeing trapped survivors
- Teams from Japan, Russia and South Korea joined the rescue efforts
What were the long term responses to the Sichuan earthquake?
- One million temporary homes to house those that had lost theirs was expected to be put up in the next three years
- Banks wrote off debt owed by survivors who didn’t have insurance
- The Chinese government pledged a $10 million rebuilding fund.
Name the case study earthquakes and when and where they happened:
Haiti earthquake, 2010
Christchurch earthquake, 2011
Sichuan earthquake, 2008
Loma Prieta earthquake, 1989, San Francisco
Northridge earthquake, 1984, LA
Bohol earthquake, 2013, Philippines
What is Eyjafjallajokull?
- It consists of a volcano completely covered by an ice cap
- It is a composite volcano
When did Eyjafjallajökull erupt?
Between March and May 2010
Why did Eyjafjallajökull erupt?
- Iceland lies on the Mid-Atlantic Ridge, which is a constructive plate margin separating the North American and Eurasian plates
- The two plates move apart due to ridge push
- As the plates move apart, magma fills the magma chamber below Eyjafjallajökull
How big was the eruption of Eyjafjallajökull?
- 3 on the VEI
What magnified the impact of the Eyjafjallajökull eruption?
- Despite a relatively low rating on the VEI, a combination of settled weather pattern with winds blowing towards Europe, very fine ash and a persistent eruption magnified the impact of a relatively ordinary event
What were the primary effects of the Eyjafjallajökull eruption?
- Day turned to night, with the ash blocking the sun
- Homes and roads were damaged
- Services were disrupted
- Crops were destroyed by ash
- Roads were washed away
- The ash cloud brought European airspace to a standstill, and cost billions of euros in delays
What were the secondary effects of the Eyjafjallajökull eruption?
- Sporting events were cancelled or affected due to cancelled flights
- Fresh food imports stopped and industries were affected by a lack of imported raw materials
- Local water supplies were contaminated with fluoride
- Flooding was caused as the glacier melted
What were the international effects of the Eyjafjallajökull eruption?
- Farmers in Kenya laid off 5000 workers after flowers and vegetables had to be left to rot at airports
- Kenya’s flower council said the country lost $1.3m a day in lost shipments to Europe
What opportunities did the Eyjafjallajökull eruption bring?
- The grounding of European flights prevented over 2 million tonnes of carbon dioxide from being released into the atmosphere
- As passengers looked for other ways to travel, many different transport companies benefitted, with Eurostar seeing a passenger increase of nearly a third
- Ash from the eruption dissolved iron into the North Atlantic, triggering a plankton bloom, driving an increase in biological productivity
- The Icelandic government had to launch a campaign to promote tourism, which significantly increased tourist numbers
What was done to reduce the impact of the Eyjafjallajökull eruption?
- The area around the volcano was evacuated
- European Red Cross Societies mobilised volunteers, staff and other resources, and providing food for the farming population living in the vicinity of the glacier, and counselling
