|Photo from my iPhone of the "foreshock".|
As the tsunami came onto land, I could only sit in my livingroom across the Pacific Ocean scared for the poor people in their cars driving on a highway - having no clue what was coming towards them. It was a sickening feeling of helplessness I am sure shared with any one else watching it happen. The wave, filled with debris and mud moved across the land in what seemed like an incredible distance for what seemed to be an eternity.
The geology student in me watched with awe at the amazing power of the processes involved to cause such a relentless wave while horrified over its devastation and the loss of human life, knowing that this was only the first wave and fearing what more could happen with the subsequent waves.
CNN and other news media reported this event as a "Megaquake". Is a "megaquake" come out of Hollywood or do they really exist. The answer is "yes". Per USGS web page entitled "Earthquakes, Megaquakes, and the Movies: Lights! Cameras! Disaster! (http://earthquake.usgs.gov/learn/topics/megaquakes.php) a "mega" is theoretically possible but as far as the geophysicists go-it is probably not likely to happen because it involves the length of the fault. They do not know of any fault (yet) that is capable of producing a 10.0 "Mega" Earthquake. Keep in mind also that we have only been "recording" earthquakes for about 100 years - the Earth has been around 4.57 Ga.
The largest earthquake recorded was in Chile on May 22, 1960 with a magnitude 9.5.For the others on the list of big (sorry none "mega") check out http://earthquake.usgs.gov/earthquakes/world/10_largest_world.php
Being curious I asked some of my FB friends what "Megaquake" meant to them. Interesting that we all have our own vision of what a MEGA is...such as an "8.0 on the Richter", "huge", "6.0 and higher", and my favorite is that which "makes a big hole that swallows up a city". Whatever the visual we might have of a Mega 10 Earthquake it is safe to say I would not want to be on the beach of a country in its tsunami path.