Sunday Nibble #57: Shook

Today, April 18, 2021, is the 115th anniversary of the Great San Francisco Earthquake, which struck at 5:12 a.m. on a Wednesday morning. Estimated to have been a magnitude 7.9 with a Mercali intensity of XI, it leveled much of the city. A lot of the rest of it was destroyed by the multitude of fires that broke out in the aftermath.

But let’s take a look at Market Street, one of the main crosstown thoroughfares in the city, on a Saturday afternoon just four days earlier. This footage has been uprezzed, colorized, and the frame rate adjusted to 60 FPS, but that only serves to make it more amazing.

For me, a few things are significant about this. One is the total chaos of the traffic patterns, with pedestrians, horse-drawn vehicle, automobiles, and streetcars all somehow co-existing without any kind of traffic signals or apparent control.

Sure, everything is probably going eight miles an hour, but it’s still a pretty impressive feat.

Another thing to pay attention to is the behavior of the people. Other than the outer trappings of clothing, you can see that they have the same needs and concerns, and even some of the same reactions to the camera passing as people do now to spotting the Google Map Car.

But something else to keep in mind while looking at this footage: A lot of these people would be dead in less than in less than 96 hours — 3,000 died in the quake — and most of what you’re looking at was destroyed. About 80% of the city either fell over outright or burned.

Collapsing was pretty common along Market which, like most big cities of the time, was full of unreinforced brick and masonry buildings. The quake even shifted the course of the Salinas River by an incredible distance of six miles.

Remember, at the time, San Francisco was the ninth largest city in the U.S., and the largest on the West Coast. (Los Angeles really hadn’t happened yet.) The City was the center of trade, finance, and culture for the west, operating a busy port known as the Gateway to the Pacific.

The quake changed everything, and while San Francisco rebuilt quickly, the vast majority of its 410,000 residents were still homeless for a couple of years. A lot of them headed south and wound up in Los Angeles, which eventually took over as the principal city of the West Coast.

Total property damage, adjusted for inflation, was over $11 billion dollars, only $6.7 billion of it covered by insurance.

Since San Francisco was a banking center, immediate cash was tied up. All of the major banks did have fireproof vaults, but they had to wait days before they were cool enough to open. Meanwhile, only one bank, the Bank of Italy, had been able to evacuate its funds and started making rebuilding loans immediately.

That company changed its name to Bank of America in 1929, but it wouldn’t have become so big without the quake. The Transamerica Tower — the famous pyramidal structure in The City’s North Beach — is named for the holding company that owns Bank of America and its corporate parent.

California in general and San Francisco and Los Angeles in particular have survived plenty of earthquakes since 1906, of course. L.A. got its first big jolt — well, the county, not the city — in the 1933 Long Beach earthquake, which led to some of the first big building code reforms.

A lot of the buildings that lost walls and façades were made of unreinforced brick, so in the ensuing years, these structures were strengthened with steel rebar (i.e., reinforcing bar) which would run through the bricks beneath floors as well as up the vertical height of internal supporting walls.

You can spot the telltale signs to this day on brick buildings. Just look for the things that look like stubby bolts sticking out of square metal plates in regular lines. Unreinforced brick buildings are still standing in all the older parts of the city, including Downtown, Koreatown, Hollywood, South L.A., and so on.

Los Angeles next got hit in 1971 with the Sylmar Quake, and San Francisco followed with the Loma Prieta quake in 1989, which hit during the opening of a World Series baseball final taking place in the city, making it one of the few quakes seen nationally in real time.

In 1994, Los Angeles was rattled by the 1994 Northridge Quake — and things have been weirdly quiet since then, really — down south and up north.

Although California did experience not one, but two 1906-worthy Big Ones on consecutive days in 2019 — a 6.4 out in the desert on Independence day, which turned out to be the intro to the 7.1 quake that hit the following evening.

This happened 150 miles northeast of L.A., and I did not feel the first one — but the second was one of the most surreal quakes I ever have experienced.

I was still working for ComedySportz L.A. and doing improv at the time, and we had just started our Friday night 8 p.m. show when the entire place started to sort of… shimmy.

It wasn’t a hard shaking by any means, but there was definitely motion. Thinking quickly, the cast onstage opened the on-set doors, which backed up to the actor entrance doors behind the stage, opened those, and hurried everyone out to the street, probably a better option than rushing them out under the (at the time) 93-year-old steel and neon marquee out front.

Meanwhile, the house manager and I stood in the lobby, wondering, “Okay. Little one nearby, or big one far away?”

We eventually strolled into the lobby and chatted with the main theatre company’s house manager as the floor continued to vibrate.

The two weirdest things to me were that while the motion was detectable, it really wasn’t alarming, just strange. The other was just how damn long it continued. Nobody timed anything, but objectively, it seemed like a couple of minutes at least, maybe more. Then it finally stopped.

Now, if we felt that one so strongly in L.A. why didn’t feel the one from the day before at all? True, the second one had 11 times the energy of the first and I was about three miles closer. Still, there should have been a jolt. Except, this is a weird quirk I’ve discovered about the place I’m living now.

For some reason, not a lot of small quakes seem to even rattle things here. I’ve been online when people nearby in North Hollywood or over at the Sherman Oaks Galleria have posted, “Good shake. Did you feel that?” And I felt nothing.

Not even a swinging blind-rod or a tell-tale creak. Hey, I’m not complaining. I remember the Northridge quake quite well, and it scared the crap out of me.

But there is one other thing. For some reason (knock wood), Los Angeles has always had very low mortality rates in earthquakes. Then again, other than 1906, it’s been the same for San Francisco.

Only 63 people died in the 1989 quake in San Francisco, despite the double-decker Marina Freeway pancaking during evening rush hour. In the Northridge quake of 1994, only 72 people died, and the death toll for Sylmar in 1971 was 64 people, 49 of whom died in a single location when the VA hospital practically sitting on the epicenter experienced multiple structure failures.

My dad had actually worked for the architectural firm that had designed and built the place, and since he’d been a photographer in the Air Force and did all of his own processing and printing, they had him come along to document the damage, part of a process that became essential in figuring out what failed and how to prevent it from happening again.

Of course, he kept a complete set of prints for himself, and I remember looking at them years later. A few photos stuck out. One was a wheelchair balanced precariously in the edge of a parking structure that had partially collapsed, so that it was hanging by its back wheels, five stories up.

Another was of a supporting column, probably three feet square, that had sheared off. This exposed the maybe 1-inch rebar inside in I’m guessing a five-by-five array. This solid, braided steel had been bent in several directions by the shaking, so that it resembled more of a hybrid S/J shape in the gap between the lower and upper parts of the column.

The most disturbing, though, was the one that looked the most normal. It seemed to be just a non-descript one-story medical building, nothing out of the ordinary. It had no broken windows, wasn’t leaning in any particular direction, and seemed to have survived.

I asked my dad about it and he said, “Oh. That was a two-story building.”

Because of things I’ve learned over the years, I will always shun living or working in any building between 4 and 8 stories, because those tend to resonate with earthquakes. This means that once the shake starts, the natural rate at which the building will propagate that shaking up its height before damping it from the bottom makes the shaking stronger.

This was particularly apparent in the Northridge quake, when a lot of fatalities occurred in an apartment complex that was… four stories tall. The top three pancaked the bottom and, since it was 4:31 in the morning, a lot of people were sleeping down there.

The other type of apartment building to avoid is what’s called “Dingbat Architecture.” Popular in the 1950s and 60s, they were a cheap-to-build style that popped up all across the Sunbelt. In Los Angeles, they’re all over the West Side, Culver City, and the San Fernando Valley.

One of their defining features is a second story that just out over open parking spaces and is supported by rather thin columns. Depending on whether the parking was on the street or in the back, the second floor above it would be either the living room and kitchen areas or the bedrooms and bathrooms.

Needless to say, being in a bedroom above a parking area like this is generally not the safest space to be in a quake. Surprisingly, it’s a lot safer to be in a much taller building.

I had friends who, at the time of the Northridge Quake, ived in a high-rise on Wilshire, near Westwood. They were on the 23rd floor of what I think was a 25-story building. Their perception of the quake? “Oh, it was just a little rattle, not worth getting up for.”

They didn’t learn the truth until they got up hours later, went to make coffee, and turned on the news.

So, yeah, I’d prefer to be in a building like that. I know it seems counter-intuitive, but here’s the thing — structures that tall naturally cancel out the shaking. Why? Well, because when the ground floor shifts, it takes a while for that movement to make it to the top.

Say that the ground floor starts out with a shift of five feet west. That will start traveling up the building, but this is an earthquake, so it’s very likely that half a second later, the ground is going to shift five feet east, and send this impulse up. And… repeat.

What you wind up with is the equivalent of a starting a very fast vibration in a very long string. And the longer the string, the lower the note, because that fast vibration slows way down. A move in one direction might only make it to the third floor by the time the next move cancels it out, and so on.

On top of that, for really tall buildings, they have to counter the very real effect of wind-sway so that occupants on the top floors don’t get motion sickness — yeah, those suckers can swing a few feet in any direction at any time. To do this, a lot of really tall buildings have counterweights built into their cores. These are basically heavy pendulums that naturally fight the building’s need to sway.

Hey — wind, earthquake, whatever. The counterweights do their job.

Barring either of the above, then a single-story, wood frame, free-standing house with everything earthquake strapped, bugout kits in the cars, and earthquake beds would be the other ideal. The one advantage over the high rise, of course, is that you’re not stuck with the choice between staying home for a week or two or walking down and then possibly back up way too many flights of stairs.

Still, my grandmother would call my mother after any report of any quake and ask her, “When are you moving back home to Pennsylvania?”

My mom would reply, “You have floods, and the effects of those last for months and years. An earthquake is over in seconds, and things get back to normal quickly.”

I always grew up thinking the same way. Give me the choice between floor, tornado, hurricane, and earthquake, I’ll take the quake — provided that I’m living somewhere, like California, that takes them seriously enough to make things as safe as possible.

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