What's beginning to make me nervous about yesterday's quake.. They think it's on the Whittier fault which last broke in 87, close to downtown Whittier. That quake seemed to be the beginning of the quake activity that spawned the series of quakes in the SoCal region thru the Northridge quake of 94.

I know we have hundreds of quakes per day, always have, always will. I just hope it's not a cycle of larger ones, starting to repeat!


Seems the one we had yesterday woulda done it, especially the buildings close to the epicenter.

I, for one, would like to know exactly how an 8.1 is "twice as strong" as an 8.0, and how an 8.0 is "1000x as strong" as a 7.0...

How is this "strength" measured? "twice as strong" (2x) and "1000x as strong" are mathematical figures. But strictly mathematically speaking, it's not even possible...

How do I reach that conclusion? Ok, lets say actual ground movement from a 5.0 can be measured in inches. Lets say the lateral motion can reach 5", and the vertical movement can reach 2". Now, I have no clue but it seems to me that shaking my house violently side to side 5" at a time and 2" would be REAL noticible, and could be damaging...

Ok, now mathematically---if 5" x 2" is the magnitude of a 5.0 quake, a "1000x stronger" 6.0 quake means side to side and vertical motion increases to 416 x 167 FEET of movement! Move up to 7.0 and we get 78.8 x 31.6 MILES of movement!

Umm....

Deep, can you shed some logical light on this? Living next to all these mountains---which earthquakes caused--- I AM interested!

i believe the richter scale doesn't measure in inches as per your example, it measure in strength,

a blast at a mining company might move a wall of dirt 10" but a blast twice as strong doesn't necessarily equate to moving that same dirt a proportional distance,

strength is measurable by factors other then what was moved a particular distance
(?)

FR, an 8.0 is 10 times as strong as a 7.0, not 1000 x as strong.

Here is the wikipedia explanation.

Maybe I should have said logarithmic instead of exponential acale.

Logrithmic scale.

Another issue for the areas most people don't think of as "earthquake prone" is that the geology is different than in California and the area affected by the quake would be larger than quakes out here. I live about 80 miles from San Francisco, and the 89 quake shook stuff here, but didn't do much damage. If you look at the map for the New Madrid fault, the area that would be damaged is big. I've seen other maps that indicate that the area of significant damage from a quake would extend into Iowa. The 182X quake rang bells in Boston.

Troop and others---My mistake on the 1000x, I was reading DeepV's remark, and just re-read it, that it meant a 5 to an 8 is 1000x (10x10x10)..

Still--- a 5 to an 8 still results in "miles" of difference measured in basic movement...

"logarithmic".... Ok, I looked it up. And I see how Richter defined earthquake "strength" using a logarithm and how using logarithmic scales come up with such enormous numbers.

So, if basic movement isn't measured, then how about "time"? Example: You have a choice--you can suffer thru an 8.0 earthquake for 1 second, or a 4.0 earthquake for 2 hours and 45 minutes (10,000x as long)...

Which would you choose? Which would ultimately do more damage?

Thinking about it, the end result of both quakes may be close...?

A 4.0 won't shake for 2 hours.

no matter how far the moving runway is moving, and no matter how fast it is moving,
the strength of the airplane engine ....

Earthquake video

(4.0 was a typo, should've read 5.0)
--I know that an earthquake won't skake for 2 hours, I meant that theoretically-- it's the only "realistic" example I can think of to explain how an 8.0 could be 1000x stronger than a 5.0.

Somehow I don't see having these two on the list as a bad thing. They're among the most liberal cities in the country. If that whole I-5 corridor from Vancouver, BC to Calif dropped off it would make WA and OR politically moderate states. Maybe each of the tree huggers over there could grab a quick latte then hug their favorite tree for the ride of their life. Wouldn't bother most of us who live in eastern WA and OR.

In our area we do sometimes feel a bit left out of all the excitement. We don't have hurricanes, floods, tornadoes or earthquakes. We do get a volcano every five million years or so, but we just had Mt. St Helens 20 years ago so we should be good for awhile. Kinda nice living in an quiet zone.

What that song from The Producers? Everyones a little...

Hey we had a 2.3 today, i don't think anyone noticed.