[conspire] Did you guys feel the 4.2 earthquake today?

[Steve Litt]

Rick Moen said on Sun, 22 Oct 2023 07:25:12 -0700

>I know you used to live in (the other) California, Steve, so you
>probably have some intuitive understanding of earthquake sizes, but the
>general public that lives outside Earthquake Country are notorious for 
>overestimating the small ones.
>
>With a 4.1, there might have been as many as one teacup knocked off a
>table in the next town over, Rio Vista.

The first seven years I was in LA, my perception of low 4's was a one
time movement. My first earthquake, summer 1981, I worked at George
Meyer TV. My boss George was an ex boxer, carried a pistol in his cowboy
boot, and was kind of a grouchy old man. I felt something like a punch
in my back and thought George punched me. Looking around, I saw George
was nowhere near me, so I asked Alvaro at the next work station what
happened. He said "Earthquake". I said "Bullshit". He said "look at the
lights". The shop lights above us, suspended on chains, were swinging.

It wasn't until October 19, 1987, that I experienced five bangers, that
are more like getting shaken than getting punched once. 1987-1996 had a
lot of five bangers near my home. My finding was that 5.1 was a little
distressing, 5.5 was worrisome, and 5.9 meant you crawl away from your
bookshelves so all the stuff on them doesn't fall on you. And at 5.9
you hear the studs in the walls cracking, and wonder if you'll live. And
who can forget Quake Wax?

As time went on I got better at estimating how far a quake was from me.
Close quakes involve a lot of high harmonic frequencies felt as sudden
jerks, whereas far quakes (of bigger magnitude) have those high
frequencies filtered out and feel like swaying: Maybe even very strong
swaying, but lacking the acceleration of close by quakes. And of course
if you're in a skyscraper, that tends to filter out some of the high
frequencies also. 

In the 1992 Landers Quake (7.2, about 100 miles away), it felt like the
entire apartment building was on a rocking chair going full tilt
boogie. And 1/3 of the apartment's pool water tsunamied out. But no
cracking studs, no feeling like Mike Tyson was punching you from every
direction.

Just as I really began to understand earthquakes, my
18 years in LA ended, I moved to Orlando, and suddenly cinderblock
walls were good and wood walls were bad.

Now, after 25 years in Orlando, I'm somewhat of an authority on
hurricanes. Maybe some time I'll tell you some hurricane stories. Or
the Chicago Big Bomb snowstorms of 1967 and 1979.

SteveT

Steve Litt 

Autumn 2023 featured book: Rapid Learning for the 21st Century
http://www.troubleshooters.com/rl21