4 underwater volcanoes have been discovered just 250km off the coast of Sydney. Scientists estimate they could be up to 50 million years old. The volcanoes are calderas, which is a large bowl shaped hole caused when a volcano erupts and the land around it collapses. The largest of the four is 1.5km across and is 700m off the sea floor. Collectively they are 20km long and 5km underwater.
They were discovered by scientists looking for lobster larvae who used sonar mapping to see the sea floor. It’s believed that they were created by the shifts in the earth’s plates that separated Australia and New Zealand around 40 to 80 million years ago. Before this discovery, the area was thought to be flat. With exciting discoveries like this, scientists have a great excuse to explore the sea floor further for more information.
Underwater volcanoes are known as submarine volcanoes
There are around 1,500 active volcanoes on the earth’s surface and an estimated 10,000 submarine volcanoes in the Pacific Ocean alone.
Volcanic eruptions in shallow water can throw material in the air, which is what created the Hawaiian Islands.