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Monday, April 18, 2016


There remains considerable confusion regarding the size of earthquakes, for newspapers first used the Richter scale, devised by Charles Richter (left) and Beno Gutenberg of the California Institute of Technology.  Not really very well explaining why, over the past couple of decades, scientists changed to something called Moment Magnitude.  Why?  MM is based on energy, which represents more closely the actual effect or damage.

Somewhat conveniently, the MM (Moment Magnitude created by Hiroo Kanamori, left, and Tom Hanks, also of CalTech) size seemed to be similar to those of Richter.  They are quite different.  Richter is based on amplitude, so a R10 earthquake is 100 times (10 times 10 because 10 minus 8 is 2) bigger than a R8.  Each MM integer higher means 32 times more energetic.  So, a M10 earthquake is 32x32=1024 times greater than a M8.  (About that volcano-shaped visual above.  To read the details, click on it.)

USGS (United States Geological Survey) site indicates that a 10 earthquake is 100 times bigger than an 8 earthquake, but 1000 times stronger.  Confused, again?  In any case, use this site, because you can find the energy difference between, say, M7.8 and M7.2 earthquakes.   Click on the earthquake calculator (store this some place in your computer) which will give you 4 times bigger, but 8 times stronger.  Ignore the 4, and in the future only use the second box, or the 8 for Moment Magnitude difference.

We thus come to those earthquakes in Japan, and South America:

  Kumamoto   7.0  16April2016    42 deaths
  Ecuador       7.8  16April2016  350 deaths

The Ecuador earthquake was 16 times stronger.  
The 1906 San Francisco earthquake, killing 3,000 and destroying 80% of the city, was estimated to be 7.8, same as the Ecuadorian.  Ever wonder what traffic on Market Street looked like in 1906.  Here is a clip.

At least these current earthquakes were not horrifically destructive.  All the above occurred over the Ring of Fire, as did the worst earthquakes of all time.

My upcoming novel on  The Venus Syndrome will involve a string of great earthquakes around the Ring of Fire inducing the release of marine methane hydrates to the surface, suddenly increasing the methane composition of our atmosphere, leading to a runaway Greenhouse Effect...unless I find a solution.

Speaking of natural disasters, Super Tropical Cyclone Fantala is now up to 175 MPH, with gusts at 210 MPH, and is projected to do something rather unusual.  Fantala is just about to turn around, backtrack southeast and approach Mauritius:


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