Geography tectonics case studies and theories

Nepal 2015

Magnitude 7.8

Sits on the boundary between the Indian and Eurasian plate

Epicentre had a depth of 15 km and was 80 km from the capital, Kathmandu

Killed 8633 people, injured 21,000, made 3 million homeless

GDP per capita was $882.31, it is one of the poorest countries in the world

Earthquake occured at midday, so people were working, reducing the death toll

Many buildings in Kathmandu were not built to withstand earthquakes, so collapsed

Mountainous terrain made it difficult for aid to reach rural areas

What pieces of evidence support tectonic plate theory?

Mantle convection- less supported theory now, involves heat from radioactive decay in the core creating convection currents that move the plates.

Slab pull- newly formed crust at mid-ocean ridges becomes denser and thicker as it cools. This causes it to sink into the mantle under its own weight, pulling the rest of the plate with it

Subduction- as crust is being created in one place, it is being destroyed in another. This crust slides under another plate where it melts, in the subduction zone.

Seafloor spreading- new ocean crust formed at mid-ocean ridges pushes plates apart

Eyjafjallajokul- E15

The eruption was only 3 on the VEI, however the direction of wind meant that the ash covered much of European airspace

100,000 commercial flights were cancelled worldwide, and 10 million passengers were stranded

European economy lost $5 billion as a result of the disruption

Effects were felt as far away as Kenya, as businesses had to dump tonnes of fresh vegetables and flowers, leading to $1.3 million being lost in revenue

Montserrat 1995

Soufriere Hills Volcano began to erupt on 18 July 1995

More than 7000 of the original 11000 residents moved to live in other countries

The capital, Plymouth, had to be fully abandoned

Much infrastructure and farmland was destroyed, leading to the collapse of the tourism and agriculture industry

A top heavy population pyramid was created, as younger people saw no economic future

Indian Ocean earthquake and tsunami, 2004

Estimated magnitude between 9.0 and 9.3, thrust the floor of the Indian Ocean towards Indonesia by around 15 metres

5 million were affected and nearly 300,000 died, with 1.7 million left homeless

Coastal areas that were hit were densely populated and low lying, meaning the tsunami could travel several kilometres inland

In some coastal villages, 70% of the population were killed

In Sri Lanka, 60% of the fishing fleet were destroyed

In Thailand, the tourism industry lost $25 million every month, and 120,000 workers lost their jobs

Haiti 2010

Epicentre was 24 km from Port-au-Prince, and the focus was 13 km deep

Haiti is a poor country with a high level of corruption in the government

A lack of building controls meant that they were poorly built slum houses, which could not sustain the ground shaking

GDP per capita was $1204.86 in 2010, and it is the poorest country in the western hemisphere

Only airport was severely damaged

Lack of sanitation caused a cholera outbreak that lasted many years

China 2008

Corrupt local government officials often ignored building codes and accepted bribes to allow builders to take shortcuts. This resulted in thousands of children dying in school buildings, whilst other buildings nearby remained standing

Area was not as densely populated as Haiti, meaning less people died

Over 130,000 soldiers were deployed within hours

Within two weeks, temporary homes, roads and bridges were being built

Japan 2011

Low level of corruption meant that building codes were strictly enforced

Many homes and offices were equipped with evacuation kits

An early warning system gave people some advance warning

Emergency drills are regularly practiced in both schools and businesses

Water from the tsunami got into Fukushima 1 and 2, which led to a nuclear meltdown

Japan responded by sending 110,000 troops, and switching all radio and TV to official earthquake coverage

The Philippines- multiple hazard zone

Causes- sits on a major convergent plate boundary, northern and eastern coasts face the Pacific Ocean, and it lies within South-East Asia’s main typhoon belts

Types of hazards and frequency- has 22 active volcanoes, and over 30% of population live within 30 km of a volcano. Landslides are common, due to a combination of steep topography, high levels of deforestation and high rainfall

Vulnerability- rapid urbanisation and high population density, 25% of population live in poverty, and many of the country’s poor live in coastal areas, where sea surges, flooding and tsunami are made worse by poorly constructed housing and infrastructure