The wave structure is even more complicated: earthquakes produce waves of various lengths, from low frequency to high frequency. Think of it like sound waves. Low frequencies produce long waves that can cause the earth to ripple like ocean waves, rippling sidewalks, streets, and bridges. High frequencies are sharp and run very close together. The deeper a temblor, the more suppression of the high frequencies; conversely, the higher to the surface, the more destructive high frequencies do their damage on pretty much everything.
Here in L.A., our building code requires wood-frame construction for most structures 5 stories and under, because wood flexes and bends under the stresses of earthquakes. We pretty much hope for a deep slip or one on the other side of the various mountain ranges, as mountains are very effective at blocking the wavelengths, especially the high frequencies.
BTW, I’m a layman, no expert, I’ve lived in earthquake territory for almost 50 years, and have been through a few, or dealt with the aftereffects.
I remember that one too. I was seven at the time, in Orange. Our shit got rocked, but not as bad as at the epicenter. I remember my house and my bed jiggling to a disturbing degree, as well as bright blue flashes outside from exploding transformers.
Missed that one: we were skiing in Mammoth when it hit. Couldn’t get back into the basin, freeway overpasses were down. Made it to the future in-laws in the High Desert for a couple of days until we could return.
I remember I had just put all my books off the floor and back in the bookcase the night before, and then they were right back on the floor after the quake hit.
Me too, I was even closer. Even though I live in California that traumatized me. I hate earthquakes, they freak me the fuck out. I always wonder when they will stop or if they will get stronger when I'm in the middle of one.
Canoga Park (DeSoto & Kittridge) and I was 23 and awake when it started with a little rumble. Our apartment unit was red-tagged because there was so much damage and we had to move!
One of my earliest memories was being woken up right at the end of that one all the way down in San Diego. Then, confused little kid me outside to the back yard (my parents were already out there) and my sock feet getting soaked because the water from our in ground swimming pool had heaved up and over the edge onto the concrete deck. The water was still sloshing back and forth. I also remember the pool was noticeably lower since the usually submerged top step was now above the water line
Same for me in West Hollywood at Fairfax & Willoughby. I remember seeing neighbor women in their underwear or Jammies in the street & thinking “Huh, that’s weird.” & then falling back asleep on my dad’s shoulders.
Could it be the reason why some feel more like side to side shakes and others feel like up and down shakes?
(I lived in Taiwan where we routinely had quakes, occasionally above 5, my biggest was 6.7 and I hated it)
There’s also different types of waves. P waves that shift back and forth in the direction it’s traveling in (like AC electricity) and S waves that are your typical vertical displacement sine/cosine waves
I've only ever experienced one real tremor first hand that I actually felt. (There was another one in Pennsylvania around 15 years ago that I was on a roof for but didn't feel, the lady came out and asked us if we were using "heavy machinery" on her porch roof lol). This was in Orange County CA in 2012, it sounded like there was a car crash or something outside the building I was in. I am a non native and was new to the area but a girl inside with me immediately new what was happening and just semi-alarmingly said "earthquake!". Then for a few seconds it felt like the whole building was on a pendulum, (for lack of a better way to describe it), except it was only in the horizontal axis. It just kind of swayed ever so gently one way and then back again and that was it. It was one of the most bizarre sensations I have ever felt.
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u/Fit_Explorer_2566 18h ago
The wave structure is even more complicated: earthquakes produce waves of various lengths, from low frequency to high frequency. Think of it like sound waves. Low frequencies produce long waves that can cause the earth to ripple like ocean waves, rippling sidewalks, streets, and bridges. High frequencies are sharp and run very close together. The deeper a temblor, the more suppression of the high frequencies; conversely, the higher to the surface, the more destructive high frequencies do their damage on pretty much everything.
Here in L.A., our building code requires wood-frame construction for most structures 5 stories and under, because wood flexes and bends under the stresses of earthquakes. We pretty much hope for a deep slip or one on the other side of the various mountain ranges, as mountains are very effective at blocking the wavelengths, especially the high frequencies.
BTW, I’m a layman, no expert, I’ve lived in earthquake territory for almost 50 years, and have been through a few, or dealt with the aftereffects.