Earthquake in Japan
Japan recently experienced one of the most massive earthquakes in history, measuring 9.0 on the Richter scale (the measurement used for earthquakes). There were also hundreds of aftershocks, some powerful earthquakes on their own.
Over 9,000 people died in the Japanese earthquake, thousands are still missing, and even more are left without homes, food or basic supplies.
Because the earthquake originated underwater, but near land, it also caused a tsunami.
A tsunami is when the ocean is forced up from the earthquake below, creating extra large waves that overflows onto land, unfortunately, often where people live. In this tsunami, some ocean waves were reportedly as high as a three-story building and travelling hundreds of miles an hour.
This interactive website from The New York Times shows satellite photos before and after the earthquake and tsunami.
The earthquake and tsunami also caused damage to some factories that produce a powerful kind of energy. This is a very big problem that remains to be solved, but there are some very brave people working on it.
So, what is an earthquake? How does it work?
Earthquakes are happening all the time. Most go unnoticed and don’t cause any damage. Deep beneath the earth’s crust is a layer of rock called ‘mantle’. There is a lot of heating and cooling that goes on here, resulting in the rocks moving. They are in huge pieces called ‘tectonic plates’. Sometimes these plates move away from each other, and sometimes they move toward each other. If they move suddenly or collide with a lot of force, it causes the ground above it to shake — an earthquake. Scientists now know where these plates meet and call them ‘fault lines’ . This makes it possible to predict where earthquakes are likely to happen. When they will happen has proven harder to predict.
Click here to watch National Geographic’s video primer on earthquakes.
Japan is located where a few of these plates meet, called the Ring of Fire . Because scientists are aware of this, and because Japan has a history of earthquakes, it was one of the best prepared countries in the world.
They had numerous earthquake sensors, over 300 tsunami sensors (above), alarms and evacuation plans . Buildings are designed to help withstand an earthquake as best as possible (you can click here to watch a building in an earthquake simulation), and they have emergency shelters ready as well.
But in this case, the earthquake was extremely powerful, and combined with the tsunami waves, was overwhelming and caused a lot of destruction and sadness. And even for those who are well-prepared, there are still usually only a few minutes’ warning to get to safety.