tectonics case studies Flashcards
1
Q
Haiti Earthquake 2010
A
- Haiti located near the Caribbean
- The epicentre near the town Leogare
25 km west of capital Port-au-Prince (population of 2 million) - Magnitude 7.0 earthquake
- 3.5 million people affected, over 300,000 people died and 5 million left homeless
- Fires spread due to gas pipe explosion
- Landslides occurred along with flooding in coastal areas.
- Long history of unstable government led to lack of resources, high level of corruption at local and national level led to a lack of resources.
- Poorest country in western hemisphere, 70% live on less than $2 a day
- Lack of coherent evacuation plan
- Many public services offered by NGOs and UN (international aid) however it was poorly coordinated
- Seismically active region
- In hurricane belt where they suffered large losses in 2008 and they had not fully recovered
- Haiti located on fault line between huge tectonic plates
2
Q
Nepal Earthquake 2015
A
- 7.8 magnitude
- Worst earthquake in Nepal since 1934
- Shallow focus
- Many people working outside in rural areas
- 50% of population affected, 9000 dead
- More than 600,000 homes destroyed
- Water tanks and pipes destroyed
- Cost of damage over $5 billion
- Less enforced building regulations
- No earthquake evacuation plan, lack of communication and education
- SARAID (a british organisation) sent a team of experts with 1.5 tonnes of specialist equipment (electrical power generators and tools)
- UK public donated £87 million to the Disasters Emergency Committee in Nepal
- Boundary of two massive tectonic plates (Indo-Australian and Eurasian)
- This plate collision produced the Himalayas mountain range.
Followed by a second earthquake 2 weeks later (8891 people died)
3
Q
Kashmir earthquake 2005
A
- Ranks as one of the most destructive in recent decades.
Magnitude 7.6 - Speed of onset was very rapid so there was no chance of evacuating to a safe area
- Damage was centred in Muzaffarabad, but spread over an areal extend of more than 1000 km^2
- Ground shaking lasted 30-45 seconds, but landslides triggered by the earthquake continued for some time, as did aftershocks up to magnitude 6.4
- 87,000 deaths, 2.8 million people displaced
- 17,000 schools destroyed or damaged
- Numerous factors including poverty, poor building construction, time of day (many children were in school), and isolation (making the rescue and relief effort difficult) help explain the impacts, but two hazard profile characteristics are also relevant:
- Frequency: the previous major earthquake in Kashmir was in 1905, so there was no ‘collective memory’ of the risks and impacts of earthquakes in the region
- Spatial predictability: Kashmir is in a ‘seismic gap’ i.e. an area of known risk that had not experienced an earthquake for some time. This should have been acted upon through education and risk awareness, which could have reduced the impacts
4
Q
Sichuan Earthquake China 2008
A
- Corrupt government officials who did not enforce building codes and regulations led to the collapse of thousands of schools killing over 5000 children while government buildings nearby remained standing.
5
Q
Japan Tohoku Earthquake and Tsunami 2011
A
- Magnitude of 9.0 with hundreds of aftershocks, most 6.0 or greater
- One of the most powerful earthquakes ever recorded
- Subduction zone, convergent plate boundary
- Massive tsunami triggered, waves up to 38 metres
- 20,000 deaths, 90% from drowning, death toll lower than expected for an event of this magnitude.
- Total damages = US$300 billion and Japan’s total GDP shrank by 3.7% between January and March 2011
- Meltdown led to to an energy crisis in many areas of Japan leading to regular blackouts and major disruption
- The Fukushima nuclear power plant was severely damaged and released dangerous levels of radiation forcing 47,000 people to be evacuated. Today, an exclusion zone of 20km still exists around Fukushima.
- Agriculture in the Tohoku region was devastated. It accounts for 3-4% of Japan’s rice production and seawater contamination of the soil affected rice crops for years.
- Fukushima safety was never assessed and was something Japan failed to take into consideration of a tsunamis effect.
- Tsunami waves exceeded protection wall height of 10m
- Earthquake system immediately sent alerts to phones
- Many households keep a basic earthquake survival kit
- Relatively shallow depth of 20 miles below surface
- Liquefaction occurred in many areas damaging over 1000 buildings
- Strict building regulations and 75% of buildings are built with earthquakes in mind.
6
Q
Turkey and Syria Earthquake 2023
A
- 7.8 magnitude and hit south of Turkey near the Syrian border and a 7.4 earthquake hit 9 hours later.
- Turkey is earthquake prone and this was the most devastating in 20 years.
- Epicentre close to densely populated cities and lots of refugee camps
- Syria focused on a civil war so lack of preparation
- Rapid international response
- Hit in the middle of the night when people were sleeping
- One year later and one in three children displaced by the earthquake is still homeless
- At least 56,000 deaths
- Prior to the earthquake, more than 15 million people in Syria were already in need of assistance in 2023.
7
Q
Indian Ocean Tsunami 2004
A
- Undersea earthquake near Sumatra, Indonesia (hit Sumatra in 15 minutes)
- Affected coasts of Indonesia, Sri Lanka, India, Maldives, Thailand and East Africa
- Up to 20 metre waves with 9.1 magnitude
300,000 deaths and 1000s reported missing, 1.7 million left homeless - spread of waterborne disease due to flooding (cholera)
- Rescue teams found it hard to navigate
- Large amounts of fishing industry destroyed
- Tourism affected (Thailand lost US$25 million in a month)
- Overall cost = US$10 billion
- Mangrove swamps and coral reefs were damaged
- 8 million litres of oil escaped oil plants in Indonesia
- All developing/emerging countries, don’t have the technology or building quality to withstand (prevention)
- Lack of education on what to do
- No tsunami early warning system
- Less natural protection (mangroves removed for tourism) in Sri Lanka
- Small, low lying islands that are harder for people to evacuate from and allowed waves to travel inland
- Epicentre close to coastal communities which were densely populated, 70% killed in some.
8
Q
Eyjafjallajokull Volcano in Iceland 2010
A
- Magnitude VEI 4
- 1 large eruption split into several phases
- Health effects - respiratory issues
- Death toll of 0
- Infrastructure destroyed by jökulhaups
- Most of the airspace over Northern and Western Europe was closed and remained closed for up to 6 days due to massive ash cloud
- Airlines were losing around $200 million per day and travellers were left stranded across the globe
- Japanese car factories had to suspend production because no parts could be supplied
- In Kenya, 400 tonnes of flowers intended for supply to the UK had to be destroyed at a cost of millions of dollars
- Poor air quality reached as far as Germany
- Largely uninhabited, only 500 farmers and their families needed to be evacuated
- Government was highly prepared - monitoring system in place
- EU implemented alternate routes for airlines
- Relatively explosive
- Glacier on top meant that many more layers of the volcano were destroyed creating a higher plume
- Plume was lighter so wind spread the gas further into the atmosphere
9
Q
Montserrat volcano 1995
A
- VEI of 3 and eruption took place from 1995 to 1997
- Half of the population were evacuated into temporary shelters in the north of the island where there was poor sanitation and food and was overcrowded
- The eruption destroyed tourism and farming (two main industries), caused a year of harvest to be destroyed
- Population decreased from 11,000 to 5000 damaging the economy due to the lack of people working, unemployment also rose from 7 to 50%
- Dormant for 350 years prior, people did not expect it to erupt and viewed volcano of less of a hazard
- Heavily monitored and scientist predicted the most likely hazards and the areas of greatest risk, allowed main city Plymouth to evacuate its population successfully
- Convergent plate boundary, oceanic meets continental increased the intensity
- Pyroclastic flows were the cause behind the 19 deaths
- Relatively low VEI meaning the volcano wasn’t as destructive.
- £41 million was donated by the British government to help the nation rebuild the island and recover the destroyed industries.
- Riots broke out among the remaining islanders as they believed the UK were not doing enough to help them.
10
Q
Mount Merapi volcano 2010
A
- Central Javas, Indonesia, VEI 4 in ring of fire
Composite volcano, eruptions from oct to nov. - 350 killed and 350,000 displaced.
- £450 million economic impact
- Ash plumes destroyed farmland however increased soil fertility.
- SO2 release caused eye & skin irritation
- Evacuation schemes were put in place for all people within 20km of the volcano but many people didn’t evacuate - many locals rely on spiritual connection to the volcano and so when these signs weren’t seen, they did not want to evacuate, also wanted to stay for better farmland as it is their livelihood, more than 1 million people live within a 10 mile radius.
11
Q
Nevado del Ruiz Volcano 1985
A
- VEI 3, Colombia, Composite volcano
- Oceanic-continental convergent plate boundary (Nazca and South American plates)
- Part of the icecap of the volcano melted, causing rivers to overflow and caused lahars
- In Amero, 20,000 of 29,000 residents were killed and 5000 injured
- Lahars killed more than 23,000 and 10,000 were left homeless
- 50km thick lahars travelled at 60mph
- Hazard maps drawn up a few months prior to the eruption which were rejected by the government as being ‘too alarmist’ resulting in no preparation time
- Took authorities 2 hours to realise an eruption was imminent
- No education or evacuation drills
- When evacuation was ordered, many people did not leave due to a thunderstorm
12
Q
2011 Japanese Tsunami economic impact
A
- Before the event, 27% of Japan’s energy was nuclear, by 2013 this had reduced to 1%
- Without nuclear reactors, Japan had to start importing more fossil fuels and globally Japan’s increased demand for natural gas pushed the price up
- Also led Germany to shut down all of its nuclear plants permanently.
- Price of electricity in Japan went up by 20%
- By June 2011, 209 companies in Japan had been forced into bankruptcy by the disaster
13
Q
Philippines as a multi-hazard zone
A
- On a major convergent plate boundary - both earthquakes and volcanoes
- North and East coasts face Pacific ocean which is world’s most tsunami prone
- Within SE Asia’s major typhoon belt, affected by around 15 a year
- Tropical monsoon climate subject to heavy annual rains
- Has 47 volcanoes and over 30% of population lives within 30km of a volcano
- Landslides are common.
- 25% of population live in poverty
- Earthquake in 2006 triggered landslides which breached the crater wall of a volcano and fell into a lake, creating a flood that washed away houses.
- In 2013, struck by three natural disasters within 3 months, an earthquake killing 200 in October, Typhoon Haiyan in November that killed 6500 and floods from a tropical depression in January killing 64 leaving Philippine government and aid agencies in a near-constant state of emergency
14
Q
Land Use Zoning (hazard mitigation)
A
- Iceland eruption 2010 used land use zoning near volcano led to only farmers being within evacuation range
- Mt Taranaki in New Zealand
15
Q
Lava Diversions (hazard mitigation)
A
- Barriers and channels successfully diverted lava flow from the 1983 eruption of Mount Etna in Italy but in general are quite ineffective.
