For an explanation, see the main splats page

• Earthquakes happen all the time, all over the Earth. Most are too small or too far away for us to feel them, but they can be measured with instruments.

• Earthquakes happen when there is movement along planes of weakness called faults in the Earth's crust, when built-up tension is released suddenly.

• Earthquakes happen as a result of tension or compression within or between plates, leading to slippage of large masses of rock along planes of weakness.

• Major earthquakes happen at faults where tectonic plates slip past each other and at subduction zones where one plate is slipping downwards under another.

• An earthquake is a shock wave that results from sudden movement when a build-up of tension is released because something gives way, releasing energy.

• Under some circumstances, rocks will move past each other along a joint plane. When two blocks of rock move, relative to each other, a fault is formed.

• The surface of the earth is made up of plates in motion, and earthquakes often happen at plate boundaries, where two plates are in relative motion.

• In 1760, John Michell suggested that an accurate timing of the arrival of the waves could help locate the center of an earthquake that had happened elsewhere.

• Earthquakes travel through the Earth as waves, following several different paths, and arriving at seismographs at different times, so the source can be located.

• Structures beneath the earth's surface are mapped either by using the information coming from earthquakes, or by looking at the reflections of small explosions.

• Earthquakes may be placed on a scale of intensity, either on the basis of the damage done at the epicenter, or in terms of the energy released.

• Points recording the same earthquake intensity are joined by an isoseismal line: in early times, these showed scientists the location of the epicenter.

• In 1935, Charles Richter invented a logarithmic scale to measure the strength of earthquakes, mainly based on the energy released in the quake.

• Seismology depends on the use of instruments to get intensity measures for earthquakes, using either the Richter scale or the modified Mercalli scale.

• Tsunamis are typically caused either by sudden underwater block movements in earthquakes, or when large blocks come off the side of undersea volcanoes.

• A tsunami is a water wave generated by sudden earth movements. Tsunamis may travel thousands of kilometers as barely visible waves before hitting a coast.

• In shallow waters, a tsunami builds up to a considerable height, and may flood a large coastal area, without any warning, far from any seismic activity.

This file is http://members.ozemail.com.au/~macinnis/scifun/splatsquakes.htm, first created on January 25, 2006. Last recorded revision (well I get lazy and forget sometimes!) was on January 25, 2006.

©The author of this work is Peter Macinnis, who asserts his sole right to the product as it is packaged here, recognising that many of the ideas are common. You are free to use this as a model to do your own version. Copies of this whole file or site may be made and stored or printed for personal or educational use. You can contact me at macinnis@ozemail.com.au, but only if you add my first name to the front of that email address -- this is a low-tech way of making it harder to harvest the e-mail address I actually read.
This site had 219,000 hits on the index page from 1999 to January 2007 and an unknown number on other pages. In January 2007, a combined counter was placed on all of the pages, counting page hits which now total