How Do Earthquakes Happen? | World Vision emergencies

Summary

The Earth’s tectonic plates, constantly shifting, cause earthquakes, especially at fault lines. These earthquakes release energy in seismic waves, and their size is measured on the Richter scale, where each number increase represents a tenfold growth in magnitude. Smaller quakes, like those under magnitude 4, are barely felt, while larger ones, especially above magnitude 7, can cause widespread devastation. Notable events like the Christchurch earthquake and the 2010 Haiti disaster show the scale of impact. Despite the unpredictability of natural disasters, it's crucial to prepare for emergencies by setting aside funds for urgent needs.

Takeaways

• 😀 The Earth’s surface is covered by tectonic plates that constantly move, often without us noticing.
• 😀 Earthquakes typically occur where tectonic plates meet, called fault lines.
• 😀 Fault lines are rough, causing plates to get stuck, leading to a buildup of energy.
• 😀 When the built-up energy exceeds the pressure, the plates slip, releasing energy as seismic waves.
• 😀 Earthquakes are measured using the Richter scale, which is exponential (each number up represents a 10-fold increase).
• 😀 Small earthquakes (around magnitude 4) are barely noticeable, while medium-sized ones (around 6) can cause building damage.
• 😀 Larger earthquakes, especially those close to the surface, can lead to significant damage like building collapses and broken pipes.
• 😀 Earthquakes measuring 7 and above can cause massive destruction, such as the 2010 Haiti earthquake that killed around 220,000 people.
• 😀 The most powerful earthquakes (magnitude 9 or higher) can lead to near-total devastation, as seen with the 2004 Boxing Day tsunami and the 2011 Japan earthquake.
• 😀 While natural disasters like earthquakes are uncontrollable, preparing a financial 'emergency fund' can help in disaster relief efforts.

Q & A

What are tectonic plates, and how do they relate to earthquakes?

Tectonic plates are large pieces of the Earth's crust that slowly move around the planet's surface. Earthquakes happen at the boundaries where these plates meet, often at fault lines. These faults can become stuck, causing pressure to build up until it is released in the form of seismic waves, leading to an earthquake.

Why don't we often feel the movement of tectonic plates?

Most of the time, the movement of tectonic plates is slow and imperceptible. The energy released by these movements is often not strong enough to be felt by humans, especially in areas far from fault lines.

What is a fault line, and why is it significant in earthquake activity?

A fault line is the boundary where two tectonic plates meet. These lines are significant because they are where most earthquakes occur, due to the buildup of pressure when the plates get stuck and eventually slip, releasing energy.

What is the Richter Scale, and how does it measure earthquake magnitude?

The Richter Scale is a logarithmic scale used to measure the magnitude of earthquakes. It's an exponential scale, meaning that each whole number increase represents a tenfold increase in the size of the earthquake's energy release.

How does the depth of an earthquake's epicenter affect its impact?

Earthquakes that occur deeper within the Earth are generally less felt on the surface, as the energy has to travel further. In contrast, earthquakes with epicenters close to the surface release more energy directly, causing more damage.

What magnitude of earthquake is typically felt by people?

Earthquakes that measure around a magnitude of 4 on the Richter scale are usually barely felt. However, those around magnitude 6, especially if the epicenter is near the surface, can cause noticeable damage to buildings and infrastructure.

Can you give an example of a devastating earthquake and its effects?

An example is the earthquake that struck Christchurch, New Zealand in 2011, which had a magnitude of 6.3. Despite its relatively moderate size, it caused nearly 200 fatalities due to its proximity to the surface and the local building infrastructure.

How do higher magnitude earthquakes affect infrastructure?

As the magnitude of an earthquake increases, the destruction grows significantly. A magnitude 7 earthquake can cause buildings to separate from their foundations, break underground pipes, and create visible cracks in the Earth. The damage becomes much worse as the magnitude rises above 7.

What was the magnitude of the earthquake that caused the 2011 Japan tsunami?

The earthquake that triggered the 2011 Japan tsunami had a magnitude of 9.0. It caused widespread destruction and led to a significant loss of life and property.

How can we prepare for natural disasters like earthquakes?

While natural disasters are beyond our control, we can prepare financially by setting aside funds in an emergency savings account. This ensures that resources are available when urgent help is needed following a disaster.