07/06/2019
Did u know? Every point on the Modified Mercalli Magnitude Scale (what we use to measure earthquakes in the US) is by a factor of TEN. What that means is this: The 7.1 Magnitude EQ in Cali this am was 8 TIMES as powerful than the previous 6.3 EQ. That also means that an 8.0 EQ is 10,000 times more powerful than a 4.0 EQ.
EQ intensity is more a measure of energy released than actual ground motion. Ground motion (what causes actual damage) is dependent on several things including soil type, the frequency and type of waves released by the EQ, and of course the amount of energy it releases as the earth slips. Just FYI, we have a bowl of jello under us here in West TN while Cali has mostly rock (Rock is the best thing to absorb EQ energy before it reaches ground level... jello not so much! 😳)
Why no major damage or injuries reported in Cali like u might think? That’s because structural engineers learned a HUGE amount about how certain structural systems perform from the catastrophic 1994 Northridge EQ. Hence, building codes have been changed significantly over the past 20 years, and structural engineers have learned how to design structures to save lives as well as how to do it somewhat economically. It’s just a fact that structural engineers saved tons of lives in Cali the past few days by being on top of their game.
Another Fact: We are due for an EQ that large in the West TN area sometime in our or our kids lifetime. Major cycles happen every 200-300 years on the New Madrid Fault. The last major ones occurred in 1811-1812... over 200 years ago. ... and the MS River ran backwards for 3 days. No joke. That’s how Reelfoot Lake was formed. Be ready!
