Do you know what can crack a rock? An earthquake! Today the scientists brought in some models of faults, which are fractures or breaks in rock where the two sides of the break have moved past each other. Faults develop over thousands of years as the earth’s solid tectonic plates float around and drift. We learned that there are different kinds of faults: Normal, Reverse, and Strike-Slip. The faults are defined by the direction the rocks move relative to the fault – ask your student to explain the differences.
We also talked about the difference between an earthquake and continental drift. Earthquakes are the fast movement that comes from a release of energy when two plates that get stuck while moving past each other suddenly release. The shape of continents and mountains also result from tectonic plates moving and crashing into each other, but in their case the changes happen slowly over millions of years. In fact, the Himalayan mountain range started forming when the India plate crashed into the Eurasian plate about 45 million years ago, and it is still growing about 1 cm/year today!