#422848 - 04/06/0904:48 PMCats predict earthquakes and electrical storms?
My husband and I didn't get much sleep last night. Misty (our 10-year-old cat) was agitated all night long. Rather than curling up and sleeping with us like she normally does, as soon as we fell asleep, she would pounce on us to wake us up. Shutting the bedroom door just made her claw at it and meow. Moving an arm or leg under the covers caused her to pounce, too. Very odd behavior for a cat we've lived with for 10 years and who usually sleeps all night. I was thinking to myself, "I wonder if there's going to be an earthquake or something?"
Turned on the morning news and there WAS an earthquake! Then again, we had severe thunderstorms here all day long with heavy rains (still raining), so maybe that was what was bothering her?
She's been sleeping like a log after keeping us up all night. I had to drink coffee, tea, and Mountain Dew to stay awake at work today. :-(
My cat and my dog do the same thing. We had a line of severe T-storms come through last night — even a tornado warning for a/b an hour — and the critters just wouldn't settle down.
And I remember back in the mid-60's when we lived on Mercer Island, WA, our dog was in the backyard and suddenly started going bananas. A minute later, WHAM! We got hit with a huge aftershock from the Alaskan earthquake of several years earlier. It registered just under 5.5 in Seattle!
Loc: Sunnyvale, CA mostly
I remember a 6.5 in Seattle, IIRC the year that Kennedy was assasinated, or perhaps 1964. I was in an old two story brick school. Ran outside in a flash. The school looked like jello, and cars banged into each other in the parking.
Loc: Sunnyvale, CA mostly
Well, it's inertia that's the killer, the tendency of the building to remain at rest while the ground moves, the tendency of the building to remain in motion when the ground stops shaking, the building goin off on all these different vectors from what the ground is going off on. All that wild Newtonian stuff starts happening. I don't know - Are harmonics a factor? Harmonics, I'd think, could shake a steel or wood framed building to pieces, but I'm not sure if there are harmonics. A different sort of phenomena (but kindasorta related) sure brought down Galloping Gerty, the old Narrows Bridge. Of course, too, we're all familiar that an army in lockstep cadence will collapse a bridge.
Depends on the building.
I'm guessing that in most quakes that steel or wood framed, reinforced or pre-stressed concrete would be okay. It would be a wild ride and scary, but they wouldn't collapse. They'd wobble, but wouldn't collapse. Masonry is a house of cards.
Thousands are killed in South American quakes, because there's shanytowns. I suspect much of the Italian wreckage is stone buildings (sadly, probably historically significant).
Of course, bets are off on a 9.5
I think they tell you to get under a desk or something, because the danger isn't a building collapsing, but sheetrock falling of the ceiling, or those overhead fluorescents, HVAC crap, whatever, shelves topping over, etc.
Loc: Sunnyvale, CA mostly
Well, looking at the videos of the wreckage, there looks to be mostly masonry, concrete block, many historical buildings, but there were a few concrete apartment buildings, too (pretty thin looking stuff, though, what looked to be 4" reinforced concrete floors, but the floors looked sort of intact/together and to have just dropped, so perhaps loosed from the walls somehow, or the walls crumpled?). Insufficient reinforcement, perhaps. Tensile reinforcement, such as pre-stressed, might be better?
It doesn't look right. Everything's way too crumbled, except for what look to have been floors. Good reinforced or pre-stressed concrete doesn't crumble like that. It's big honkin chunks held together. On many of the masonry buildings, it looks as though they used mesh as we do, for the stucco (or plaster?), indicating that many were perhaps not that old and historical, so one wonders why in the twentieth century (or nineteenth) one would build with masonry construction in an earthquake zone (well, we did a lot of that, too, though).
As demolition companies would attest, a properly constructed concrete building is a very long and tedious demolition - They don't just topple - They're broken down piece by piece.
I would suppose with a poorly designed and constructed concrete building, that the base or ground floor could crumple, and that would bring the building down (but I'd guess with the base obliterated, with possibility of rest of the building more intact? //with some buildings// decoupled from the inertial collisions, with the collapse of the base floor?). Then the building wreckage would be different, with the acceleration/deceleration.
Now, aren't modern skyscrapers taproot or a suspension system. The cladding would be the danger, perhaps, ripping from the attachments? I also believe they're designed for the weird vortex-like phenomena in high wind (and there could also be, I suppose, something similar to venturi effects in skyscraper canyons), low pressure cavitation (suckage). But I'm not sure how the cladding or whatever would handle an earthquake, but can imagine on deformation of the overall building geometry, that there's pretty good shear on the attachments or a fracturing of the edge margin areas around them, or a fracturing of the cladding. Anyway, big heavy chunks earthbound at high speed.
Loc: Central Florida
"Are harmonics a factor?"
Most definitely. For instance, in the 1985 Mexico City earthquake, most damage was confined to buildings between 6 and 15 stories tall. Every building has a resonant frequency that is determined mostly by how tall it is.
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