What caused the third largest earthquake ever measured, and the resulting 2004 Indian Ocean Tsunami?
The continents and oceans on earth are part of the earth’s upper layer, or Crust. The Crust is made of solid rock about 5 km – 80 km thick. But the Crust is not one single piece of rock. It is divided into separate “tectonic plates”. And each tectonic plate floats on the layer below the Crust – the Mantle. Tectonic plates can move apart from or into each other, or slip past one another, or break up. This is a constant process. And since the plates are constantly moving it also means that continents and oceans are also not static, but float with the tectonic plates on which they lie. The plate on which India lies, the Indian plate, is part of the larger Indo-Australian plate. This plate is moving North-North East, at about 6 cm per year. To the north and east of the Indian plate is the Eurasian plate. The Indian plate started colliding with the Eurasian plate about 55 million years ago, and the collision is still continuing. This collision is causing the denser Indian plate to “su...