 |  |  |  |  |  |
| | | | | |
 | |||||
  |
When we talk about international trade and the Boomerang Box, we often say that countries all over the world are connected. What we usually mean when we say that is that when countries trade with each other they are connected because they share goods or food or money, or because people travel between them. But the countries of the world are connected by much more than international trade. One way we are all connected is in the way our countries - wherever they are on the earth - rest together on the giant plates that make up the earth's surface. These plates are called the lithosphere and they float on the earth's mantle. As the plates float and move, they sometimes bump into each other and cause earthquakes. Earthquakes are actually an everyday event. Every year, there are about 6,000 earthquakes as the earth's plates slip and slide past one another. However, most of these earthquakes are too small to be felt by you or me. Only about 500 quakes a year can be felt by people standing on the ground and, of these, only about 15 or so cause any damage. But a major earthquake can cause enormous damage no matter where in the world it strikes. People and animals can be killed, buildings, bridges, roads, and sewer systems destroyed, and landslides, fires, or giant waves (tsunamis) triggered. Survivors of an earthquake may find themselves without food, water, or a place to live. And all because of a simple bump between two plates on the earth's surface. Earthquakes are measured based on the power of the shock waves they create. These waves are called 'seismic waves' and they can be measured from far away. They are measured using something called the Richter scale. The Richter scale is 'logarithmic.' That means that each number you go up on the scale represents an earthquake that is ten times more powerful. So, an earthquake that measures 6.0 on the Richter scale is ten times more powerful than an earthquake that measures 5.0. Earthquakes that measure higher than 6.0 are considered dangerous. Earthquakes can strike anywhere in the world, wherever the earth's plates come together. And 2001 has already brought a number of dangerous earthquakes in different parts of the world. Washington State, USA, was hit by the Nisqually Quake - measuring 6.8 - on February 28th. This was a big quake, but luckily it struck about 30 miles underground so that it was not as strong on the surface as it was underground. Many buildings and bridges were damaged, but no one was killed. El Salvador in Central America has been hit by two major earthquakes recently. The country experienced a 7.6 quake on January 13th and a 6.6 quake on February 13th. These two quakes have devastated the country. Altogether, the two quakes killed over 1,000 people and injured over 8,000 people. Nearly 100,000 homes were damaged and nearly 500 landslides added to the damage. Gujarat, India also experienced a major earthquake recently. On January 16th, a shallow and very strong 7.7 quake struck. The damage was extreme with nearly 20,000 people killed and over 150,000 injured. What do we do when disasters like these earthquakes strike? Well, usually we show just how connected our countries are, by rushing to help the people in need. That's what the Boomerang Box has been doing this spring carrying relief supplies to India… and that's a type of connection between countries that is every bit as powerful as our connection to the plates on the surface of the earth.
Study Questions How do earthquakes work? And what can you learn about fault lines and earthquake preparedness? Use the library and Internet to learn more. The U.S. Geological Survey at www.usgs.gov has information on earthquakes that have happened all over the world. Write a one-page paper about what you learn.
Test your mapping skills! 
Check out past Trade Topics entries! | |
|
|
|
|
|
|
|