Case Study: Earthquakes 🌍

students, earthquakes are one of the most important examples in IB Geography SL because they show how people, places, and development levels affect disaster impacts. In this lesson, you will learn the key ideas behind earthquake hazards, how to describe and explain them using geography terms, and how to use a case study in exam answers. You will also connect earthquakes to the wider theme of geophysical hazards, which includes other hazards such as volcanic eruptions and tsunamis. By the end, you should be able to explain why some earthquakes cause far more damage than others, even when they have similar magnitudes.

Learning objectives:

Explain the main terminology connected to earthquakes.
Apply IB Geography reasoning to earthquake impacts and responses.
Connect earthquake case studies to the wider theme of geophysical hazards.
Use evidence from a real earthquake case study in exam-style explanations.

What is an earthquake? 📉

An earthquake is the sudden shaking of the ground caused by a rapid release of energy in the Earth’s crust. Most earthquakes happen because of plate tectonics. The Earth’s lithosphere is broken into large plates that move slowly over time. When plates grind past each other, collide, or pull apart, stress builds up along faults. A fault is a fracture in the rock where movement has occurred. When the stress becomes greater than the friction holding the rocks in place, the rocks slip and release energy as seismic waves.

The point inside the Earth where the earthquake starts is called the focus or hypocentre. The point directly above it on the Earth’s surface is the epicentre. Earthquake effects are often strongest near the epicentre, but damage can spread widely depending on the type of ground, building quality, depth of the focus, and the size of the earthquake.

A key term is magnitude, which measures the amount of energy released. In modern geography and seismology, the moment magnitude scale is commonly used. Another important term is intensity, which describes the observed effects and damage at a particular location. This means one earthquake has one magnitude, but it can have many different intensity levels across different places.

Why do earthquake impacts vary? 🏚️

students, not every earthquake becomes a major disaster. The difference between a hazard and a disaster depends on vulnerability, exposure, and preparedness. A hazard is a natural event that may cause harm. A disaster happens when the hazard seriously affects people and property.

Several factors control earthquake impacts:

Magnitude: Larger earthquakes release more energy.
Depth: Shallow-focus earthquakes usually cause more surface damage than deep-focus earthquakes.
Distance from epicentre: Areas closer to the epicentre usually experience stronger shaking.
Building quality: Poorly designed buildings are more likely to collapse.
Population density: Dense urban areas have more people and infrastructure at risk.
Time of day: A quake at night may affect sleeping residents differently from one during the day.
Secondary hazards: Earthquakes can trigger landslides, liquefaction, fires, and tsunamis.

A useful IB Geography idea is that disaster risk can be thought of as a combination of hazard and vulnerability. High-income countries often have stronger building codes, emergency services, and public education, so they may suffer fewer deaths from the same magnitude earthquake than a lower-income country.

For example, an earthquake in a wealthy city with strict construction standards may still cause costly damage, but fewer deaths. In contrast, a similar event in an area with weaker buildings, less preparedness, and limited response capacity may lead to severe loss of life. This is why geography focuses not only on where hazards occur, but also on who is exposed and how resilient they are.

A case study example: the Haiti earthquake of 2010 🇭🇹

One widely used earthquake case study is the Haiti earthquake of 12 January 2010. This event is a strong example for IB Geography because it shows how vulnerability can turn a natural hazard into a major disaster.

The earthquake had a magnitude of about $7.0$ and occurred near the capital, Port-au-Prince. It was a shallow-focus earthquake, which made the shaking especially destructive. The epicentre was close to a densely populated area, and many buildings were not built to withstand strong ground movement.

Why were the impacts so severe?

Haiti had several vulnerability factors before the earthquake:

Many buildings were poorly constructed.
Building codes were weak or not widely enforced.
Roads, hospitals, and government services were limited.
Emergency response capacity was low.
Many people lived in crowded urban areas.

The immediate impacts were extreme. Large numbers of buildings collapsed, including homes, schools, hospitals, and government structures. This made rescue and medical response much harder. The earthquake also damaged the port and roads, which slowed the delivery of aid. Official figures estimate that more than $200{,}000$ people died and more than $1{,}500{,}000$ were made homeless. These numbers are often used in geography lessons to show how a single event can create both direct and indirect impacts.

The secondary impacts were also serious. People lost access to clean water, shelter, healthcare, and jobs. Disease risk increased in temporary settlements. Long-term recovery was slow because the country already faced economic and political challenges.

Short- and long-term responses 🚑

Earthquake responses are usually grouped into immediate, short-term, and long-term actions. This is important in IB Geography because you may be asked to evaluate how well a place responded.

Immediate responses are actions taken during or just after the event. In Haiti, search and rescue teams worked to find survivors trapped under rubble. Emergency medical aid was provided by local and international groups. Temporary shelters were set up for displaced people.

Short-term responses focus on restoring basic services. These included distributing food, water, and medicine, clearing rubble, and creating temporary camps. International aid played a major role, but the destroyed transport network made this difficult.

Long-term responses aim to rebuild the country and reduce future risk. In Haiti, reconstruction included rebuilding homes, schools, and infrastructure. However, progress was slow. This shows an important geography point: recovery is not only about physical rebuilding, but also about governance, money, and resilience.

When evaluating responses, you can ask:

Were lives saved quickly?
Was aid coordinated effectively?
Did reconstruction reduce future vulnerability?
Were all groups helped equally?

How to use this case study in an exam ✍️

In IB Geography SL, a case study should not just be memorized as a list of facts. You need to use it to explain patterns and support arguments. students, think of the Haiti earthquake as evidence for a bigger idea: earthquakes are natural events, but disaster severity depends heavily on human vulnerability.

A strong exam answer might do the following:

Define earthquake terminology clearly.
State the magnitude, location, and date.
Explain the physical reasons for impact, such as shallow focus and proximity to the epicentre.
Explain the human reasons for impact, such as weak buildings and high vulnerability.
Describe responses and evaluate their effectiveness.

For example, if asked why earthquake impacts vary, you could explain that the Haiti earthquake caused huge losses because it hit a densely populated city with weak infrastructure and limited emergency services. You could contrast this with earthquakes in countries that have stricter building standards and better preparedness. This comparison shows geographic reasoning because it links place, development, and hazard outcomes.

Another useful skill is comparing primary and secondary impacts. Primary impacts are the immediate effects of shaking, such as collapsed buildings and deaths. Secondary impacts happen later, such as homelessness, disease, unemployment, and disrupted services. In many cases, secondary impacts last longer than the shaking itself.

Earthquakes and the wider theme of geophysical hazards 🌋

Earthquakes fit into the broader Optional Theme — Geophysical Hazards because they are caused by natural Earth processes. Geophysical hazards include events related to the lithosphere and tectonic activity, especially earthquakes and volcanic eruptions. In some cases, earthquakes can also trigger tsunamis, which belong to the wider hazard chain.

This topic helps you see connections between different hazards. For example:

An earthquake can cause a landslide on steep slopes.
An undersea earthquake can produce a tsunami.
A volcanic eruption may be linked to tectonic plate boundaries.
The same ideas of vulnerability and resilience apply across different hazards.

That means the earthquake case study is not just one isolated event. It helps you understand the bigger IB Geography idea that hazards become disasters where people are exposed and poorly prepared. The same physical process may have very different outcomes depending on development level, governance, and planning.

Conclusion ✅

Earthquakes are a major geophysical hazard because they can cause sudden, widespread damage and long-term social and economic disruption. The key geography terms are $magnitude$, $intensity$, $focus$, $epicentre$, and $fault$. The Haiti earthquake of $2010$ is a strong case study because it shows how weak buildings, high vulnerability, and limited emergency response can turn a magnitude $7.0$ earthquake into a major disaster. students, when you study this topic, focus on both the physical process and the human context. That is the core of IB Geography SL thinking: hazards are not just natural events, but human disasters shaped by place, development, and preparedness.

Study Notes

Earthquakes are caused by the sudden release of energy along faults in the Earth’s crust.
The point where the earthquake starts is the focus or hypocentre; the point above it is the epicentre.
Magnitude measures energy released, while intensity measures effects at a location.
Earthquake impacts depend on depth, distance from the epicentre, building quality, population density, and preparedness.
Primary impacts happen immediately; secondary impacts happen later and can last longer.
Haiti’s $2010$ earthquake had a magnitude of about $7.0$ and caused over $200{,}000$ deaths and more than $1{,}500{,}000$ homeless people.
Haiti is a strong case study because it shows how vulnerability increases disaster severity.
Responses include immediate, short-term, and long-term actions.
Earthquakes are part of the wider Optional Theme — Geophysical Hazards because they are linked to tectonic plate processes.
In exams, always combine factual evidence with explanation and evaluation.