Make your own free website on Tripod.com

Frequently Asked Questions

EARTH MOVEMENTS

Q. Which workers are most exposed to radioactivity?
A. The workers most exposed to radioactivity in Australia are not miners such as those at the uranium mines in the Northern Territory. They are the guides at the famous Jenolan Caves in the Blue Mountains near Sydney. These guides work only short shifts because there are high levels of natural radon gas released from minerals washed down in the underground rivers. The heavy gas cannot escape because the caves cannot be ventilated, for fear of destroying the cave formations.
 
Q. Why does the Earth ‘hum’?
A. The constant movement of the earth's crust causes a humming sound that can be detected by low frequency sound receiving devices.
 
Q. Are there mountains under the ocean?
A. There are mountains as high as Mt Everest under the ocean.
 
Q. What is the largest volcanic eruption observed by humans?
A. In 1883, an Indonesian island named Krakatoa erupted with a force equivalent to 150 million tonnes explosive. The noise apparently was felt on the western Australian coast. The shock wave travelled around the world seven times.
 
Q. How is pumicestone made? Why is the stretch of water between Bribie Island and the mainland near Brisbane called Pumicestone Passage?
A. Pumicestone is an igneous volcanic rock formed when lava was thrown upwards into the air. Air bubbles were trapped inside the rock so it can float on water!
Originally the Glasshouse Mountains, north of Brisbane in Australia, were volcanoes and threw out many pumicestone which are still to be found floating in the waters near Bribie Island.
 
Q. How are tsunamis formed?
A. Tsunamis are tidal waves caused by underwater earthquakes.