Earthquakes
Study Questions: Geology 1) What is the primary source of energy for surface processes of the Earth? 2) What is the primary source of energy for internal processes of the Earth? 3) How can a temperature difference between different parts of a body result in motion? 4) List at least two methods of constructing a geological time scale. 5) The present tectonic environment in California is thought to have existed for about 20 Million years. What percentage of the Earth's history does this represent? 6) The earliest records of earthquakes in California date back to about 1800. What percentage of Earth's history does this represent? 7) List two ways in which the discovery of natural radioactive decay had a major impact upon geology. 8) How far back does the Phanerozoic time scale extend, and why does it not extend further back? 9) Why are sedimentary rocks suitable for keeping relative time and why can't they provide information about absolute time? 10) Before the advent of plate tectonics, it was thought that heat flow from under the ocean would be much lower than under the continents. Why? And why is it not the case? 11) What are the main subdivisions of the Earth's interior and what distinguishes them?