1 The Voyage of Continent Australia
The jigsaw puzzle of continental and oceanic plates that make up the earth’s surface
is in constant motion, driven by the earth’s molten core producing the circulation of
rock within the earth’s mantle. Moving only centimetres per year, the earth literally
quakes as these plates diverge, collide and grind past each other. When they collide,
the denser oceanic plates sink under the lighter continental plates, subducting marine
sediments deep into the interior of the earth. Here, these water-filled sediments become
superheated and the resultant steam, gas and molten lava can erupt explosively at the
earth’s surface. Indonesia is the most tectonically active region in the world and its
many volcanoes bring destruction to the people and the environment there, but at the
Map of the earth’s tectonic plate boundaries11