“Scientists Fear the BIG ONE is Coming as FOUR Major Earthquakes Strike in 48 Hours” exclaimed The Express in proper tabloid fashion. Japan is rocked by four quakes in two days, each over 6 on the Richter scale. Not a terrible quake, a 6.0 or so, but a rocker and scary enough. There were even a couple deaths. Japan handles temblors like this well. They are used to them. Of course seismologists worry that they might be foreshocks announcing a real monster of a quake, though Japan is used to those too. Alas, there is nothing unusual at all about earthquake clusters like the four The Express is screaming about, especially in Japan, where four tectonic plates–the vast North American, Eurasian, and Pacific plates, and the smaller Philippine plate–grind against each other with slow violence. The northern half of Japan is mostly part of the North American plate, the Southern half is the Eurasian plate, and the Pacific plate is forcing itself beneath the Eurasian plate (a process called subduction) at a rate of about three and a half inches a year. Sometimes the subduction process gets stuck for a few years and then, after enough pressure builds up, it moves forward with a jolt. Sometimes it’s a little jolt. Sometimes it’s a 6 point jolt. And sometimes it’s a jolt so big everything shakes to pieces and the sea comes roaring back in a tsunami. That’s Japan. We have earthquakes in California as well, of course, but no one is subducting anybody. Rather our plates are slowly grinding past one another, so that the shaking, even at its worse, cannot get to the same level as Japan is prone to. In Alaska, though, where the Pacific plate is being subducted by the North American plate, you can have earthquakes of astonishing violence, like the one that leveled Anchorage in 1964.
The Express story hinted that the quakes in Japan could set off quakes in, say, California. As if somehow earthquakes were all interconnected. And while earthquakes on the same (or on linked) fault lines can be related theoretically, ones thousands of miles away can’t possibly be, because there would not be enough energy released from an initial quake to go through thousands of miles of solid rock from Japan to California. And the fact that there are four major quakes in 48 hours in a general region–say across East Asia–is just chance, as there are hundreds of quakes 6+ every year and sometimes a few of them happen within a couple day stretch.
Remember that earthquakes, in the grand tectonic plate scheme of things, are extremely minor events, just little quivers, nothing. While to us they can be terrifying, devastating, even catastrophic, in geologic terms they are just everyday things. After all, every great mountain range in the world is the result of literally millions of earthquakes. When you think how few large earthquakes you have lived through living in, say, Los Angeles, you get an idea of the time scale in building mountains, and how we can play no role at all in that process whatsoever. Nothing alive can. Mountains rise and erode as if life never existed at all. Because in the grand scheme of things life means next to nothing, really. Life is just a process for making coal or limestone.
That Puente Hills fault that caused the quake out in Brea yesterday (in 2014) is the one that terrifies geologists. They used to think the Elysian Park fault was the killer–our house sits right atop that one–but it now appears to be dormant. But in the last ten thousand years the Puente Hills fault has snapped in a huge way four times, and each of those quakes was a 7 plus on the Richter scale. That would be ten times at least as powerful as the 1994 Northridge quake. Furthermore, the Northridge fault directed its energy away from downtown (with explains how places as far away as Fillmore were leveled) but the Puente Hills fault would direct its energy towards downtown. I suppose that is how people in downtown last night felt the shaking of a quake centered in Brea so strongly (and why we scarcely noticed while we were out in Tujunga). The Puente Hills fault stretches from roughly Brea to Beverly Hills, and it has three active areas–Brea, Whittier (remember the Whittier Narrows quake in 1987?) and here. And I mean right here…downtown Los Angeles is square in the middle of it, and the zone’s width goes from just below USC to about where I am in Silver Lake. In fact, being that I am typing this while literally astride the Elysian Park fault, our place is just outside the Puente Hills fault zone, not that we wouldn’t shake like hell anyway. We wouldn’t shake as bad as people on the nearby flatlands, their homes built as they are on layers of sediments, but we’ll be shook up something awful. I dread the thought of it. It won’t be boring, anyway. (There was another shaker on the Puente Hills Fault in January 2015 that got everyone’s attention just a few blocks from us but that we literally did not feel at all. Not even the cat noticed.)
The Puente Hills fault is a thrust fault. Everyone knows how the San Andreas fault (which cuts through the Antelope Valley down into the Coachella Valley fairly distant from us) is between two plates that slide past one another. Every once in a while the plates get stuck and then snap apart. The movement is horizontal. West of the fault goes north, east goes south. But a thrust fault is vertical movement, that is the fault zone is thrust upward. As the tectonic plates move, pressures build up in the rock beneath us. Stress fractures appear, which we call faults. Those pressures reach a point where something has to give and when they do, you get an earthquake along one of those stress fractures. Most of the times these quakes are imperceptible to anything but a seismograph machine. Sometimes they are strong enough to wake the cat. Sometimes they are strong enough to set off a flurry of chatter on Facebook. And sometimes they are bigger than that. In a really big quake along the Puente Hills fault zone, the ground will suddenly lurch up a meter or two, meaning that the part of town from USC up through downtown will be instantly elevated above the area south of it. Think of it this way: all the north south streets–Alameda, Hope, Flower, Figueroa, Hoover, Vermont, etc.–would suddenly be unusable, because at some point past Exposition Boulevard there would be a three or even six foot drop straight down. Not gradual, not sloping, but straight down. You will need a ladder to proceed down the sidewalk. That is what huge quakes on thrust faults do.
No one knows when this will happen. It will happen. There is no way it will not happen. But it could be before I finish this post, or it could be in a couple thousand years. Every city on the West Coast from Anchorage (trashed in 1964) to San Diego (my first earthquake memory) faces the prospect of a disastrous earthquake. That is the geologic reality of living on the Pacific Rim. It’s scary as hell if you think about it much, so I don’t think about it much. We try to be a little prepared, though. Just in case. Ya never know.
I wasn’t going to post this. Like maybe it’s too creepy. But maybe people should know. A lot of you do already. But it’s amazing how many residents of this area have no idea what might happen if we roll seismic snake eyes.
Now I need a drink.
And you will too, after seeing this Visualization of a Puente Hills Earthquake. It is in real time, and the color key represents the degree of shaking. Blue is the least violent, green more so, yellow even more and on into the red. You notice that the more intense shaking–the greener, yellower and even red colors, are in the flatlands between downtown and the Palos Verdes Peninsula. The sediments of the basin there are up to six miles deep, laid down mostly when the land was ocean bottom and compressed into the easily crumbled rock that you see in some roadcuts. But the meandering Los Angeles River has over thousands and thousands of years left deep, sandy soils that once made for terrific farmland and now are really prone to intense liquefaction when the ground shakes. There was intense damage in this area after the Northridge quake, probably all of which was caused by liquefaction. The ground under overpasses on the Santa Monica Freeway lost its solidity and the poor things just toppled. That’s an impressive sight, and immense concrete bridge in pieces on the ground. That was the destructive power of liquefaction. And that epicenter was much further away than this hypothetical Puente Hills quake would be. The damage from a 7 magnitude quake in the Downtown area would be exponentially greater. A lot more overpasses would topple. A lot of houses will be red tagged. What a mess.
Probably be some great yard sales, though.
(No idea when I wrote most of this….)
Next time you go up the 5 through the Grapevine, and come to the place where Highway 138 comes in, you’re crossing the San Andreas Fault. Fault zone, really. It’s fairly wide. You can see it on the highway itself, which is in permanent repair–shifting earth makes for busted up concrete. And you can see it in the land itself…take a look at that rippled terrain. It smooths out again as you go towards Gorman. And south of there is just steep hills and canyons/valleys. But right there at the junction you can see how the terrain is being pulled apart and pushed together as the plates grinds past one another. And dig the intense folding in the exposed layers of rock. Hard to imagine the force that can warp and bend solid rock like that. People and everything we are are nothing compared to that sort of force. If you’ve ever been through a serious earthquake you know what I mean. That feeling of being very small and squishy and fragile as huge forces erupt under our feet. And then there’s the whole deep time thing. Our lifetimes barely measure a century, pile up those centuries and you’ve got a hundred, maybe two hundred thousand years and, I’m sorry to say, that’s about as far as human time goes. If you want real recorded history, then you’ve got only a few thousand years. Big things happen in a few thousand years, big human things, civilizations rise and fall. But all those things are nothing in deep time. Just a finger snap. A flicker. A match flaring and going out again. A human lifespan is a nanosecond of deep time. A million years is a small integer in deep time. But the earth happens in deep time. The plates move in deep time. Continents drift in deep time. Rarely does human time and deep time intersect, though when they do it is with terrifying suddenness. The world shakes and big beautiful concrete ribbon freeway exchanges collapse.
You’ll notice that the folding along the rest of the drive is more linear…it still dips and curves, but it appears to be under much less compression, and hasn’t fragmented. I love how you go from the Pacific Plate to the North American Plate right there. The North American plate is some ancient rock, man. Going way back. In the very center–the American Midwest–it’s what they call a craton, a really ancient slab of continent. Flat, with thousands of feet of soil on top. In California the North American plate is what they call orogenic, all tore up and mussed up and stretched and pulled and broken from the plates sliding past one another. All our beautiful California topography and localized ecosystems and microclimates are the result. I think, if I remember my revisionist geology right, that the stuff on the Pacific Plate side is probably all kinds of islands and the like compressed into a mess as the Pacific plate pushed east. So southern California is a conglomerate of junk all moving northeast at a remarkably fast (tectonically speaking) three to four inches a year, while the North American plate is land that has been there a billion years through the comings and goings of various supercontinents. It’s moving, too–the entire surface of the globe is moving and will till the planet’s insides grow cold–but it moves at a comparative crawl and in a southwestern direction. The two massive plates grind past each other. Sometimes they stick in places, and when they unstick all hell breaks loose. That’s what happened to San Francisco in 1906…the plates came unstuck.
If it weren’t for earthquakes and the occasional panic when someone points out a fault running through the middle of Hollywood (perfectly visible to geologists) people would never see the evidence of slowly moving earth all around them. You’d never notice it here in Los Angeles, too many distractions, too many things to do, too many buildings and streets and parking lots and whatever cover it all up. There are faults running every which way through the Los Angeles basin–I’m sitting right on top of the Elysian Park Fault as I type–but people kind of pretend they aren’t there. And though potentially dangerous, these are all just little things compared to the San Andreas. Faults in this town are the result of all kinds of local pressures–basically the Pacific Plate being squeezed up against the North American and everything getting scrunched up and cracking like plaster on a slowly buckling wall–but the San Andreas is the big time, two plates coming together. The earth’s core is so hot that the mantle around it has liquid properties and the crust, the stuff we live on, sort of floats atop it, plates wafting in currents, pushed by the mantle emerging from great fissures in the ocean floor and forming new crust. The plates are shoved into each other. Sometimes one pushes on top of the other and the loser is subducted back down into the mantle. Earthquakes of terrifying power can occur then, bigger than San Francisco’s even–Anchorage was virtually destroyed by one like that in 1963. Japanese civilization sits precariously atop another such subduction zone. Luckily here in California the plates exist in relative peace, pushing past each other. A little rough, but nothing tectonically existential. I know this may seem relative if you live in, say, San Francisco or Santa Cruz or the Coachella Valley or even Gorman. A 7.5 or so earthquake is just as scary to think about as a 9.5. You’ll still lose all the fine china. But the street won’t suddenly drop twenty feet.
Up the Grapevine you can see the effects of all this movement. You can see it because that whole pass is pretty much beyond the reach of civilization. Miles and miles of beautiful nothing and the occasional ranch house or empty farm or inevitable McDonalds. There’s all that land there, all those hills and bluffs and cliffs revealing tens of thousands or hundreds of thousands or even, in spots, millions of years of slow geologic history. You can see the forces at work. But only a frame at a time. Our entire lifespans are only a few feet in geologic time. If you live to be eighty years old and live in Los Angeles the land will have moved north with you on it maybe eight feet. Two hundred human lives laid end to end would see the Pacific Plate move northwest less than a mile. That’s it. And though relatively fast in tectonic terms, it’s not much progress. Just about nothing. Meaningless even. People will come through the Grapevine a thousand years from now and see all those rocks, and the rocks will be in the same place, pretty much, as when I last looked. A few landslides will shift things around, some flash floods. Otherwise, though, you’d never know anything had moved at all. A thousand years from now (and one hundred and twenty five feet from here) you and I will be long forgotten. That is just a hint of geologic time. That is the deep time we flit about in, changing nothing.
(This was a quick Facebook post and is a bit of a mess but I’ll leave it as is….)
In wonderfully telegraphic prose, a comrade posted “earthquake in japan now. pacific rim is heating up. cali needs to be ready?”
A ha. Rocks. Earthquakes. The very earth beneath our feet. After myself, my other favorite subject. I actually decided against a career in geology for a career in punk rock, epilepsy and writing about me. Say a’a, the doctor said, and out flowed this:
About 90% (I began) of the world’s earthquakes happen in the Pacific Rim’s Ring of Fire, so it’s shaking all the time. There’s no connection between California and Japanese quakes, though. Our quakes happen because the eastern spreading portion of the Pacific plate (and a smaller connected plate) are being pulled under the North American plate, while Japanese quakes happen because Japan sits where the western spreading portion of the Pacific plate is being pulled under the plate that eastern Siberia is on. The fault zones are unconnected.
In California the plates are sort of moving past one another, the Pacific plate sliding beneath the North American plate at an angle, while in Japan the plates together slam head on. Subduction is not a pretty process. Geology, mostly, is violence in slow motion, a few inches a year. Those undulating layers you see in California road cuts are layers once horizontal subjected to immense pressures. The bend slowly. Sometimes, though, you see layers shattered, as if they exploded. That’s because often they did. You might be looking at the frozen remains of earthquakes. Rock busts into fragments and the surface above shakes. Sometimes a little. Sometimes a lot. The San Andreas Fault is where two tectonic plates slide past each other at about an inch and a half per year. Sometimes they catch and remain stuck till enough pressure builds up that they uncatch and destroy San Francisco. But there is vastly more energy to be released when plates collide directly than when they slide past each other, hence the frequency and power of Japanese quakes. Japan actually is the result of two (or is it three, I can’t remember) plates being dragged under (or subducted) beneath two other much larger plates. In Japan you have these two or three separate collisions (not just the one I alluded to in an earlier paragraph, keeping things simple), and each collision is vast and inexorable, and all that friction and compression and crunching and pushing causes nearly incessant earthquakes of sometimes unbelievable power and destructiveness. Indeed, Japan itself is a result of these collisions, with sea bed forced upward and vast amounts of the liquid rock mantle being released from cracks in the crust through volcanos. Geologically it’s a helluva mess, volatile and unstable and virtually quivering and literally quaking with pent up seismic energy. Just be thankful, Californians, that we have nothing even remotely similar to this. (They do in Alaska, which is how Anchorage was leveled in 1964, the Pacific Plate suddenly lurching violently and shoving itself beneath the North American Plate, leaving one side of the street thirty feet higher than the other.) The San Andreas may pop off every couple generations. Japan has giant quakes every couple years. They handle them with aplomb. Their buildings don’t fall down. Port au Prince Tokyo is not. It’s not even Fillmore.
As for the devastating Nepali quakes these past several days, those are the result of India slowly crashing into Asia for the past 50 million years. It’s weird to think that in that span of time there have probably been a million huge quakes in what is now the Himalayas, just like these last two. A million quakes raising the earth six inches each time is what created the Himalayas. The top of Mount Everest was at the bottom of a shallow sea a half billion years ago. The rocks way up there are full of fossil crinoids. Imagine how many earthquakes it took to raise them 30,000 feet into the air.
Next time you pass through a roadcut, take a look at the rocks exposed. The violence in those bent and twisted layers is incredible. So much power moving a couple millimeters a year. The earth moves in millions of years. We are nothing, our entire lifespan a geologic nanosecond, like we aren’t even here.
Still, I love rocks.
Here I am watching UCTV again. I love UCTV. It’s basically lectures by people smarter than me. Sometimes I understand them. The linguists, the historians, this paleontologist showing funny slides of the Burgess Shale. He’s talking about the Permian extinction, at the dawn of the Triassic. He says that 96% of all species disappeared. That I knew. This is what they can deduce from the fossil record, all the extraordinary variety of life in the Permian was reduced to virtually nothing as the Triassic began. But then he said that it appears that the mega-extinction occurred in a span of two hundred thousand years. That I did not know. I had heard millions of years, even low millions, but two hundred thousand years? He reeled off the theory, the evidence, the processes of annihilation involved, and how they came out to around 200,000 years. That is fast. It may not seem fast to us–language itself may only be two hundred thousand years old–and four generations of people living to the limits of human life expectancy, from the birth of the great grandmother to the death of the great granddaughter, barely stretches two hundred years. But in the expansive span of evolution and even greater expanse of geologic time, two hundred thousand years is less than a minute in a day. It’s almost instantaneous. Annihilation, when it happens en masse, happens suddenly. Apparently one of the few therapsids–a mammal like reptile, closer to us than to dinosaurs–survived, which was good for us, otherwise I wouldn’t be here writing this and you reading it or doing any homo sapien things. And we’ll end this thus, otherwise it will be a book.
The site of a fresh mudslide from a distance always looks so cleanly cut, as if a shovel dug into the wet ground and simply lifted the hillside away and dropped it gently a couple hundred feet down. Grass and shrubs and even small trees are often left in place. Come by in a few weeks, after the rains have stopped and the sun is out and you can see wild flowers in all their colors where people and houses used to be. Sometimes the people and houses are still there, after the survivors had given up hope of ever digging them out again. The old hillside becomes their tomb, and the flowers just make it pretty.
Once you recognize the shape you can see mudslides all over the place in southern California, recent ones and old ones. They’re not uncommon. In fact they’re usually so small as to even be newsworthy. Someone loses a backyard and the people below get their pool filled it. It doesn’t even have to rain for those, a broken water pipe will do it. Even a sprinkler left on during a vacation. But it’s rain that really gets the ground moving. Hillsides become soaked, the soil becomes mud, and mud being heavier than dry soil, eventually, at a certain point, that ground begins to slide downward, and continues to slide until a new center of gravity is found and the movement ceases. One of the amazing things about mud is how the water holds the dirt together into a mass while at the same time makes that mass easy to move. An entire hillside, thousands and thousands of tons of dirt, can suddenly move as if my command in one piece, holding its composition and even keeping its topsoil in place. With all our engineering prowess and computer modelling we can’t do that. We can’t make a hillside move in such an orderly fashion down a hillside in one piece, and in a matter of seconds. We can start avalanches and rock slides, sure, those are easy. We can blow a mountain to kingdom come to get at what’s inside. But we can’t just make a whole hillside shift downward a few hundred feet without disturbing the flowers. That’s a matter for rain and gravity and fluid mechanics.
Mass wasting is the technical term, gravity making shit fall down. Rocks falling down all the time in California. Our mountains and hills are very young and haven’t been worn down smooth yet by erosion, and besides that a lot of the material is made up of fragile sedimentary rock that breaks up and falls back down easily. Quake, rain, flash flood,. high winds, fire zone…everything comes down out in Southern California. If you ever drive along the base of the mountains in Pasadena, say, you come across these enormous catch basins designed to capture all the stuff that begins falling down in heavy rain…including boulders that weigh hundreds of tons. Those things used to roll for miles, trashing everything in their paths. I love this state, always exciting.
The effects, as in Oso, Washington, can be horrific. Sometimes merely destructive. In 1995 there was a very impressive mudslide above the village of La Conchita, between Ventura and Santa Barbara. For months afterward the 101 there was covered with a thin layer of mud, and if you looked up at the bluffs you could see a classic view of a hillside dropped down a couple hundred feet and resting atop what had been a street.
For a while afterward houses stood with their insides protruding through their front windows. Just imagine how much mud could make a house do that. Down the other end of the street the mud had buried houses completely. Then in 2005 the hillside came down again but much more quickly (here’s some terrifying video) and took out more streets and houses. Ten people died in their homes. A whole family was entombed in one, save for the father, who had stepped out to go to the store. He spent days walking the streets calling out the names of his children. No one knew what to say. When I saw the news of that mudslide in Washington, saw the scar where the hillside had been, and the hillside now where the houses had been, I thought of that man again, looking for his children.
On the back slope of the ridge I live on here in LA you can see another old slide. There’s a big concrete wall holding it back off Riverside Drive. I remember sitting at a gas station years ago and wondering what the hell that big slab was there for and then saw the shape of an old mudslide. It was like a miniature version of that hillside in La Conchita, scooped out of the ridge and deposited fifty or sixty feet below. I asked a few other people if they saw anything there. They said no. I guess you have to know what to look for.
Once the scar is grown over again and green, it doesn’t look so menacing. You have to stare hard to realize what you’re seeing. Once you do see it, though, you can never miss it again. You can, in your mind’s eye, take the piece of the hillside that is now below it and pick it up and put it back where it was and see what a perfect fit it makes. But there it is, at the foot of the ridge. I can’t imagine that this slide buried anything. Some ground squirrels, maybe, a few tarantulas. Some California poppies. Some of the snow birds wintering on the street there (we call that stretch the Riverside Riviera) might have found their beat up vans engulfed in a foot or two of mud. But I don’t think there were any structures there. Somewhere down there on Riverside Drive was an old gay bar, but I don’t know where exactly. Some of the older guys from the neighborhood–all gone now–told me stories about the place. A total dive, they said, a wreck. Every winter they had to open the back door so the water coming off the hill could flow through the bar and out the front door and onto Riverside Drive. Some winters the place would be full of mud. It was a popular place, though. But that bar, whatever it was called, is long gone. From what I was told–and this is just hearsay–the place was condemned as a hazard because the ground behind it was unstable. So maybe it was where the hillside came down. But I have no idea what happened to it. Perhaps the patrons just got tired of muddy shoes.
Anyway, they’re talking about another El Nino rainy season next year, which we desperately need, so more of these ugly gaping smiles where hillsides used to be will appear throughout Southern California. Especially in burn areas. Next summer well after the rains (should they come) you should be able to see them. By the following spring, after a few rains again and the grasses turn the hillsides green, they’ll really stand out, big brown scars where green slopes should be, and below them, mustard and lupine and poppies waving in the breeze, yellow and purple and red. Pretty.
Mudslides have been one of the prime shapers of our topography here in southern California. Mudslides on the hillsides, debris flows down the mountains, earthquakes and floods . You don’t like the lay of the land now, just wait till the next big rain. Something’s bound to give. Just don’t be there when it does.
(Great National Geographic article on the slide: Mudslides Explained: Behind the Washington State Disaster)