Plate Tectonics- Seismicity Case Study

L'Aquila Earthquake, 2009

Key Facts

• Date: 6th of April 2009
• Magnitude: 6.3
• Eurasian and African Plates at a destructive plate margin

Location

L’Aquila is historical city located in central Italy. It has a population of 70,000.

Causes

• The earthquake was along the north-south fault line, along the Apennine mountain range and was caused by the Eurasian and African Plates at a destructive plate margin. 
• The African plate is subducted below the continental Eurasian plate. 
• It was a magnitude 6.3 earthquake on the Richter scale, with a shallow focus of 5.5 miles. 
• The earthquake struck at 03:32 local time on 6th of April 2009. Buildings in the area were poorly constructed as many were very old and had not been reinforced. 

Effects

Economic:

• Cost Italy $15 billion.
• Thousands of buildings destroyed. (Including old tourist attractions such as L’Aquila cathedral.)
• A bridge in Fossa collapsed.
• Fires spread in destroyed/ damaged buildings. 

Environmental:

• 1000km2 affected by surface ruptures, rock falls and landslides.
• Wildlife habitats affected, loss of biodiversity in some areas. 

Social:

• 307 deaths. (Mainly from collapsing buildings)
• 1500 injured.
• 70,000 people made homeless- housed in tent cities but 10,000 accommodated in hotels along the coast.
• Aftershocks (reaching 5 on RS) hampered rescue efforts and lead to more deaths.
• People had to leave the area (young people for work) to find jobs 

Response

"Could 179 lives have been saved? Italian scientist warned of killer earthquake a WEEK ago - but was silenced."

In October, 2012, seven Italian earthquake scientists were found guilty of manslaughter for their role in failing to communicate the risk of a possible earthquake, shortly before a powerful 2009 earthquake killed more than 300 people in the city of L’Aquila, Italy.

Aid

National aid:

• All Italian mobile companies sent free minutes and credit to all their pre-paid customers in Abruzzo, suspended billing to all post-paid customers and extended their coverage with additional mobile base stations to cover homeless camps.
•  In addition, some companies sent free mobile phones, SIM Cards and chargers for those who lost their mobiles, and set up a national unique number to send donations to, by placing a call or sending an SMS. 
• Poste Italiane sent to homeless camps some mobile units acting as Postal Office, to allow people to withdraw money from their accounts as well as their retirement.
• Many companies, such as pay-tv SKY Italia, suspended billing to all customers in Abruzzo, and offered some decoders to homeless camps to allow them to follow the funerals and the news. 
• Ferrovie dello Stato offered railway sleeping carriages to host some homeless people, and offered free tickets to all people and students living in Abruzzo. 
• AISCAT declared that all toll-roads in Abruzzo would be free of charge. 
• All tax billing for all Abruzzo residents has been suspended by the government, as well as mortgage payments. 

International aid:

• Prime Minister of Italy Silvio Berlusconi refused foreign aid for the emergency, saying that Italians were "proud people" and had sufficient resources to deal with the crisis. However he singled out the United States, announcing that he would accept aid for reconstruction: "If the United States wants to give a tangible sign of its solidarity with Italy, it could take on the responsibility of rebuilding heritage sites and churches. We would be very happy to have this support." and suggested the USA help rebuild "a small district of a town or a suburb".

Plate Tectonics- Seismicity Case Study

Haiti Earthquake, 2010

Key Facts

• Date: 12th January 2010
• The poorest country in the western hemisphere, based on HDI
• Politically unstable
• $GDP per capita = $697
• Magnitude: 7.0 
• Epicentre was 25km west of the capital Port-au-Prince
• Depth: 13km

Location

Haiti is a small Caribbean country, on the island of Hispaniola, South East of the USA and East of Cuba. Its capital city is Port-au-Prince.

Causes

• The earthquake was caused by the North American Plate sliding past the Caribbean Plate at a conservative plate margin. Both plates move in the same direction, but one moves faster than the other. 
• The pressure that was built up because of the friction between the 2 plates was eventually released causing a magnitude 7 earthquake on the Richter Scale with an epicentre 16 miles West of Port-au-Prince and a shallow focus of 5 miles. 
• The earthquake struck at 16:53 local time on Tuesday 12 January 2010. Port-au-Prince is a very densely populated area and is extremely poor.

Effects

Primary (caused directly by the earthquake)	Secondary (result from primary effects)
316,000 people were killed and 1 million people were made homeless.  3 million people were affected by the earthquake	1 in 5 people lost their jobs because so many buildings were destroyed.  Haiti’s largest industry, clothing was one of the worst affected
250,000 homes and 30,000 other buildings, including the President’s Palace and 60% of government buildings, were either destroyed or badly damaged	The large number of deaths meant that hospitals and morgues became full and bodies then had to be piled up on the streets
Transport and communication links were also badly damaged by the earthquake	The large number of bodies meant that diseases, especially cholera, became a serious problem
Hospitals (50+) and schools (1,300+) were badly damaged, as was the airport’s control tower	It was difficult getting aid into the area because of issues at the airport and generally poor management of the situation
The main prison was destroyed and 4,000 inmates escaped	People were squashed into shanty towns or onto the streets because their homes had been destroyed leading to poor sanitation and health, and looting became a real problem

Development

Development Indicator	Value
GDP per capita (average income)	$1,200 per person each year
People living in poverty	80% of people live on $2 or less per day
Life expectancy	62 years old
People per doctor	0.25 doctors per 1,000 people
Adult literacy rate	53% over 15 years old can read/write
Access to clean water	46% of people have access to clean water

Responses

Short Term	Long Term
$100 million in aid given by the USA and $330 million by the European Union	98% of the rubble on the roads hadn’t been cleared restricting aid access
810,000 people placed in aid camps	1 million people still without houses after 1 year so still have to live in aid camps
115,000 tents and 1,000,000+ tarpaulin shelters provided	Support for people without jobs, which equates to nearly 70% of the population, through cash/food-for-work projects
Healthcare supplies provided to limit disease	Temporary schools created and new teachers trainee
Lack of immediate aid through poor planning, management and access meant that people had to try and rescue each other	Water and sanitation eventually supplied for 1.7 million people
4.3 million people provided with food rations in the weeks following the earthquake

Plate Tectonics- Seismicity Case Study

Japanese Earthquake & Tsunami, 2011

Key Facts

• Date: 11th March 2011
• Magnitude: 9
• Pacific Ocean
• Pacific plate subducted beneath North American Plate

Location 

A massive 9.0-magnitude earthquake struck Japan, Friday afternoon, on 11 March 2011. The quake was centred 130 kilometres to the east of the prefecture’s capital, Sendai. A tsunami was sent crashing into the country’s north-eastern coast. It was originally reported at a magnitude of 7.9, but later was upgraded to 8.9 and then to a 9.0. It lasted 6 minutes. 

Causes 

• Japan is located on the east edge of the Eurasian Plate. 
• There was a build-up in strain energy as the Pacific plate subducted under the Eurasian plate. This strain energy eventually overcame the frictional force holding the plates in place, and was released as earthquake waves.
• The tsunami is a secondary consequence of this initial movement. The Eurasian plate was down warped (dragged down) as the Pacific plate descended. When the strain energy was released this section of the Eurasian plate “popped” or bounced back upwards. This displaced the water above in the Pacific Ocean causing a Tsunami wave to ripple radially outwards. This was known as a megathrust earthquake. 
• The aftershocks occurred as the strain energy was passed along the fault, causing further quakes. 

Impact 

• Japan was largely prepared for the earthquake and many buildings remained standing afterwards, but it was not prepared for the subsequent Tsunami. A tsunami warning extended to at least 50 nations and territories, as far away as South America. 
• The tsunami waves that reached heights of up to 40 meters in Miyako and which, in the Sendai area of Honshu, travelled up to 10 km (6 mi) inland. 
• The island of Honshu was moved 2.4 m east and shifted the Earth on its axis by estimates of between 10 cm and 25 cm. 

Social: 

• Residents within a 20 km radius of the Plant were evacuated. 
• The official death toll report confirmed 15,854 deaths, 26,992 injured and 3,155 people missing across twenty prefectures. 
• Around 4.4 million households in northeastern Japan were left without electricity and 1.5 million without water. 
• All of Japan’s ports had to close at least temporarily during the disaster, and 10% of the fishing ports were damaged. 

Economic: 

• The yen fell sharply but recouped most of its decline several hours later. Tokyo stocks fell. 
• 130,000 buildings totally collapsed and another near 700,000 buildings partially damaged. 
• The earthquake and tsunami also caused extensive and severe structural damage in north-eastern Japan, including heavy damage to roads and railways as well as fires in many areas, and a dam collapse. 
• The economic losses are thought to be huge, given Japan’s highly developed infrastructure and level of development there was a lot to be damaged. The World Bank estimated cost was US$235 billion, making it the most expensive natural disaster in world history. 
• Estimates of insured losses from the earthquake alone ranged from US$14.5 to $34.6 billion. The Bank of Japan offered 15 trillion Yen (US$183 billion) to the banking system to normalize market conditions. 

Environmental: 

• The most worrying impact was on Japan’s famed nuclear power industry. There were several nuclear incidents but the most notable was 3 nuclear meltdowns at the Fukushima power plant. This cause contamination of the sea and land, and force the evacuation of local residents. A brave team of nuclear power plant workers battled bravely to prevent the nuclear reactors overheating completely and exploding. 

Response 

• Many people got outside during the earthquake and the response to the Earthquake was reasonably good. The warnings from the JMSA also helped save lives. Many people did not react quickly enough to the tsunami alert, and even if they did the 20 minutes or less warning was insufficient for the people to escape. 
• The JMA and government did a good job of monitoring and getting warning to people, and this probably saved many lives. 
• Over 340,000 displaced people in the region needed catering for, and issues included shortages of food, water, shelter, medicine and fuel for survivors. 
• The Japanese government responded by sending in specially trained people such as the Self-Defence Forces, a domestic response. 
• Many countries such as the UK sent search and rescue teams to help search for survivors. NGOs and other Aid agencies helped too, with the Japanese Red Cross reporting $1 billion in donations.

Plate Tectonics- Seismicity Case Study

Indonesian Boxing Day Earthquake & Tsunami, 2004

Key Facts

• Date: 26th December 2004
• Magnitude: 9
• Indian Ocean
• Eurasian and Australian Plates
• Strongest earthquake for 40 years

Location

On 26 December 2004 a tsunami occurred in the Indian Ocean. 
Thirteen countries were affected, the worst being Indonesia. Indonesia was hit by the tsunami first. Forty-five minutes later the tsunami reached Thailand.

Causes

• It was the result of the Indio-Australian Plate subducting below the Eurasian Plate. 
• It was caused by an earthquake measuring more than magnitude 9. 
• The earthquake caused the seafloor to uplift, displacing the seawater above.
• In the open ocean the tsunami measured less than 1 metre high.
• The tsunami travelled at speeds up to 800km per hour.
• When the Tsunami reached the shores, the height of the wave increased to 15 metres in some areas.

Economic Impact

• Local economies were devastated, the overall impact to the national economies was minor.
• The two main occupations affected by the tsunami were fishing and tourism. The impact on coastal fishing communities and the people living there, some of the poorest in the region, had been devastating with high losses of income earners as well as boats and fishing gear.
• While the tsunami destroyed many of the boats vital to Sri Lanka's fishing industry, it also created demand for fibreglass reinforced plastic catamarans in boatyards of Tamil Nadu. Since over 51,000 vessels were lost to the tsunami, the industry boomed. However, the huge demand has led to lower quality in the process, and some important materials were sacrificed to cut prices for those who were impoverished by the tsunami.

Environmental impact

• Severe damage on ecosystems such as mangroves, coral reefs, forests, coastal wetlands, vegetation, sand dunes and rock formations, animal and plant biodiversity and groundwater.
• The spread of solid and liquid waste and industrial chemicals caused water pollution and the destruction of sewage collectors and treatment plants threaten the environment.

Social Impact

• 250,000 deaths
• PTSD
• 2 million people were made homeless
• Starvation and disease
• No access to clean water - contamination from sewage and decomposing bodies
• Due to the many deaths and destruction, the people of South East Asia have found it hard to return to a normal way of life.

Responses

• Short-term aid, such as water purification tablets, temporary housing and medical supplies were given from international countries.
• The governments of the affected countries reacted reasonably quickly but were reliant in many cases on OUTSIDE AID due to the magnitude of the disaster and the lower level of economic development of the places affected. Countries sent aid teams immediately.
• An early warning system for Tsunami has now been put in place in the Indian Ocean, through co-operation from many governments.
• The UK government's Disasters and Emergency Committee established an emergency fund almost immediately.
• The DEC Earthquake/Tsunami disaster appeal fund stood at £32 million, up £7 million in one night from the 31st of December. At one point the DEC was receiving around £15,000 a minute in donations via the phone and Web
• MEDCs such as the UK sent dog teams, forensic experts and equipment to help identify bodies and clean up after the Tsunami.

Plate Tectonics- Seismicity

Effects of Earthquakes

Primary effects

• Ground shaking. 

Secondary effects

• Soil liquefaction- is there is a high water content in the soil looses mechanical structure and behaves as a liquid
• Landslides/avalanches- slope failure due to ground shaking
• Collapse of buildings/transport systems
• Destruction of water, gas and electricity provisions
• Fires- ruptured gas mains and fallen electricity pylons, causing sparks
• Flooding- Dam bursts, ground water, mains water 
• Disease and food shortages
• Tsunamis 

Tsunamis

Tsunamis are caused as a result of natural primary hazards meaning they are a secondary hazard mostly as a result of tectonic activity, usually a shallow focus earthquake.

The water is vertically displaced and waves move outwards as the sea floor is deformed as the earthquake strikes.

Tsunami waves travel very fast on the open ocean but their destructive power comes from their towering heights which they attain as they approach the coast

Waves travel at 800km/h, but due to enormous wavelength the wave oscillation can take 20-30mins to complete a cycle and has amplitude of 1metre.

Ninety percent occur in the Pacific basin. 

Tsunami effects

The effects depend upon:-

• The height of the waves and the distance they have travelled
• The length of the event that caused the tsunami
• The extent to which warnings can be given
• Coastal physical geography, both offshore and in the coastal area
• Coastal land use and population density

Management of Tsunamis

Prediction:

• Pacific Ocean Tsunami Warning System - gives an early warning - however there is no such thing in the Indian ocean (poor suffer more) 
• Communication in MEDCs e.g. telecommunications better than in LEDCs which prevents prediction reaching the poor in LEDCs 

Education:

• Local population aware of hazards in MEDCs and are taught how to respond 
• Nothing like this in LEDCs 

Protection:

• Buildings along a coastline have preventative measures taken to lessen tsunami impact 
• Building walls are built perpendicular to the shore, so waves can go through them rather than knocking them over. 
• Stilts used to prevent damage 
• Forest planting between the coastline and buildings as trees rapidly slow waves down and cause them to lose a lot of energy, mangrove forests.

Plate Tectonics- Seismicity

Causes of earthquakes

The movement of the earth’s plates due to the rising and falling convection currents in the asthenosphere, means there is a slow build up of pressure in the rocks. When this pressure is released, parts of the surface experience intense shaking for a few seconds, this is called an earthquake.

The point at which the pressure is released is called the focus, and the point immediately above the focus on the surface is called the epicentre. The seismic shock waves have their highest level of energy at the focus; energy decreases as the waves spread outwards.

The depth of the earthquake is significant:

• Shallow 0-70kmkm
• Intermediate 70-300km
• Deep 300-700km

Seismic waves

Seismic waves travel out from the focus; there are three types of waves:

P Waves- (primary)

• Are the fastest and shake the Earth backwards and forwards.
• These travel the fastest and move through solids and liquids.
• These travel in all directions from the focus, like a ripple

S- Waves- (Secondary)

• Slower 
• Move with a sideways motion
• Shaking the Earth at right angles to the direction of travel. 
• They cannot move through liquids but are more damaging.

L & R Waves- (Surface Waves)

• These travel near to the surface 
• Slower than the two mentioned already & they’re more destructive than either.
• They include L waves (long waves) 
• L waves cause the ground to move sideways
• Raleigh waves which make it move up and down. 

Distribution

Earthquakes usually happen around plate boundaries, the most destructive occur at destructive faults especially if there is a subduction zone, also at transform faults such as the San Andreas Fault.

Earthquakes can also happen away from plate boundaries and are associated with the reactivation of old fault lines, such as the 2002 earthquake in Dudley, 4.8 on the Richer scale, along the old fault line known as the Malvern lineament.

Human activity is also thought to trigger earthquakes examples include subsidence of deep mine workings and extreme building.

Measuring earthquakes

There is two ways of measuring earthquakes:

Richter Scale

• Logarithmic scale
• Each point represents a ten-fold increase in the amount of energy involved
• Measured using a seismograph 
• Scale of 1-10

Mercalli Scale

• Measures the intensity of the event
• Impacts
• Scale 1-12

The Richter Scale and the Mercalli Scale don’t match up exactly, and event 12 on the Mercalli Scale, is only a 8.5 on the Richter Scale.