Japan’s Chernobyl? Radiation pressure fears at Fukushima plant

8.9 earthquake hits Japan Tsunami Warning! across west coast of U.S

Japan residents rescued from home during 2011 Earthquake Tsunami

Hawaii, US West Coast Under Tsunami Warning after Massive Japan Earthquake

Over 1,000 feared killed as megaquake strikes Japan

9.0 Japan earthquake shifted Earth on its axis

“…Friday’s earthquake off the eastern coast of Japan was upgraded to a magnitude 9.0 by the Japan Meteorological Agency, the Kyodo News agency reported Sunday.

The agency’s scientists probably had access to new data, said U.S. Geological Survey seismologist Susan Hough. “If they’ve upgraded, I expect USGS might follow suit,” she said, adding that it was not unusual for magnitudes to move up or down by 0.1, because large earthquakes can be tricky to measure.

“It’s not surgical precision,” she said.

Other details are emerging. The quake probably shifted the position of Earth’s axis about 6.5 inches, said Richard Gross, a geophysicist at the Jet Propulsion Laboratory in La Canada Flintridge, in an e-mail. …”

“…The Japanese have the best seismic information in the world,” said Lucy Jones, chief scientist for the Multi-Hazards project at the U.S. Geological Survey, at a Saturday news conference at Caltech in Pasadena. “This is overwhelmingly the best-recorded great earthquake ever.”

Already, just over 36 hours after the quake, data-crunchers had determined that the temblor’s force moved parts of eastern Japan as much as 12 feet closer to North America, scientists said, and that Japan has shifted downward about two feet. …”

http://www.latimes.com/news/nationworld/world/la-sci-japan-quake-science-20110313,0,5782113.story?track=rss

Background Articles and Videos

What is the rating scale of earthquakes?

Less than 2.0 : Micro : Not felt.
2.0-2.9 : Minor : Not felt, but recorded.
3.0-3.9 : Minor : Felt, but rarely cuse damage.
4.0-4.9 : Light : Noticable shaking of items, damage unlikely.
5.0-5.9 : Moderate : Damage to poorly constructed buildings, unlikely damage to specially designed buildings.
6.0-6.9 : Strong : Destructive for up to 100 miles across populated areas.
7.0-7.9 : Major : Serious damage over large areas.
8.0-8.9 : Great : Serious damage over areas of several hundred miles.
9.0-9.9 : Great : Devastating damage in areas thousands of miles across.
10.0+ : Great : Yet to be recorded

Read more: http://wiki.answers.com/Q/What_is_the_rating_scale_of_earthquakes#ixzz1GOx3dzFn

How Earthquakes Work

by Tom Harris

“…The Richter Scale is used to rate the magnitude of an earthquake — the amount of energy it released. This is calculated using information gathered by a seismograph. The Richter Scale is logarithmic, meaning that whole-number jumps indicate a tenfold increase. In this case, the increase is in wave amplitude. That is, the wave amplitude in a level 6 earthquake is 10 times greater than in a level 5 earthquake, and the amplitude increases 100 times between a level 7 earthquake and a level 9 earthquake. The amount of energy released increases 31.7 times between whole number values.

The largest earthquake on record registered an 9.5 on the currently used Richter Scale, though there have certainly been stronger quakes in Earth’s history. The majority of earthquakes register less than 3 on the Richter Scale. These tremors, which aren’t usually felt by humans, are called microquakes. Generally, you won’t see much damage from earthquakes that rate below 4 on the Richter Scale. Major earthquakes generally register at 7 or above.

Richter ratings only give you a rough idea of the actual impact of an earthquake. As we’ve seen, an earthquake’s destructive power varies depending on the composition of the ground in an area and the design and placement of manmade structures. The extent of damage is rated on the Mercalli Scale. Mercalli ratings, which are given as Roman numerals, are based on largely subjective interpretations. A low intensity earthquake, one in which only some people feel the vibration and there is no significant property damage, is rated as a II. The highest rating, a XII, is applied only to earthquakes in which structures are destroyed, the ground is cracked and other natural disasters, such as landslides or Tsunamis, are initiated. …”

Killer Tsunamis

Introduction to Logarithms

Logarithms in the Real World

http://www.japannuclear.com/nuclearpower/program/location.html