So how bad is “San Andreas”?

OK, there are a lot of “here are the problems with San Andreas” sites out there.  But you know GG loves to sit through these things, laughing hysterically at parts where the audience begins to wonder just what is going on. After Dwayne Johnson claimed that this was vetted by an earthquake expert, Tom Jordan (said earthquake expert) made it clear that little of his advice was incorporated into the script.

By the ways, if you are looking for a brutal drinking game, keep track of how many times somebody says “my God”. (With subtitles here in Luxembourg, “Mein Gott/Mon Deiu” practically seemed burned into the screen).

Anyways, the ones who probably have the biggest beef with this film are the architects (er, a skyscraper splitting in two?  Really? It would be hard to get a house of cards to fail that way, let alone a building).  But let’s amuse ourselves and, obviously, spoilers abound (though realistically, none of these are big shocks if you have seen a preview or any other disaster movie in the last 40 years).

We know that we’re in trouble right at the start when a car careens over a cliff and comes to the most improbable stop in a place that doesn’t really exist.  Had the car been animated and was holding on for dear life, it couldn’t have been less realistic. But not geoscience…

The review of big earthquakes exaggerated the Hilo tsunami from the 1960 Chilean earthquake–it was plenty large (over 10m–about 35 ft) but not quite the size mentioned in the film. Very dramatic review in class with nicer graphics than most of us manage.

(And BTW, while they show aerials of Caltech–Beckmann Auditorium being most obvious–nothing else really resembles what you would find in South Mudd, where the Seismo Lab is located).

Anyways, we move on to the noble earthquake seismologist testing out some magnetic field gear on small earthquakes in Hoover Dam when they get an off-the-scale reading and then the earthquake strikes!  Of course people can run even with these strong ground motions (not).

Um, look, if your technique gives you a minute or less of warning, it isn’t buying anybody much (would be worthwhile but not a game changer).  Obviously this is a pure plot device so we can get foreshadowing and so you just have to go with it (though folks have hoped to get something from magnetic fields, nothing has come close to panning out to date). Anyways this starting 7.1 goes on longer than the M9s later in the film, which is really odd (a M9.5 would go on for a loooong time; just ask folks in Tokyo).  Hoover Dam shatters (only after the new bridge bypassing the dam top fails), sending a flood downstream. Not sure really why the dam would fail (dam failures in earthquakes are more often from landslides causing a major wave or failure of fill dams; an earth fill dam in 1906 was actually cut by the surface rupture and survived). Anyways, they say there are no faults in the area, which is a stretch of sorts (there are tons of old faults near Hoover Dam–the area was the site of an early paper using fault slip data to recover ancient stress fields–and Quaternary faulting is found just to the north adjacent to Las Vegas–BTW, Las Vegas would have been trashed by this earthquake, with liquefaction failures all over the place; the casinos, which have generally invested in more substantial structures, might be the only things left functioning.  How did the filmmakers miss that?  Even Godzilla’s recent adversaries didn’t miss a chance to clobber Sin City).

Later our hero seismologist speculates that the plate boundary now runs up to Las Vegas and then out the Garlock Fault…so, um, how does the southern San Andreas fit into this? And good luck with the kinematics of this geometry…

Buildings fail in San Francisco from the southern San Andreas earthquake.  Seems unlikely (especially because the kind of motion you’d expect wouldn’t be the kind they showed occurring in San Francisco). At that distance it would be more of a rolling motion. Lots of swinging chandeliers, motion-sick high-rise residents, and sloshing swimming pools. Not so many chunks of concrete falling in underground parking garages.

The damage throughout the movie is really unrealistic. Stuff shakes off of buildings, pieces fall off that are structural, whole regions are crushed, buildings fall over.  Anyways, not great. A large building keep sinking–but the skyscrapers in San Francisco are grounded on bedrock (similar to Manhattan), which is not prone to liquefaction (so buildings falling over is unlikely). The building tipping in Christchurch from that earthquake is probably one of the more extreme examples of such liquefaction failure of a tall building; this requires the building to lack connection to sturdier rock below.

Bakersfield gets clobbered.  Hard to see that happening as shown.

Lots of the earthquakes are way too short and way too simple.  Seems like an odd complaint for a movie that glories in stuff collapsing too much, but real shaking actually changes during the event.  Guess they figured the audience had enough shaking in the first (smallest) earthquake.

While the big ripples of the earthquake waves are really cool, they are really not going to be visible (the surface waves that would have the largest amplitudes are also longer period and so quite broad).

Some characters encounter the San Andreas fault after the first big earthquake but before the second and find a huge deep crevasse.  This alone is ridiculous, but the offset across the crevasse is left-lateral, not right lateral like the San Andreas (kind of a needless blunder). And as Lucy Jones said, if there was a big chasm going really far down, there would be no friction and so no way to make the second big earthquake. Seems like another worthless plot device (we need to change over to an airplane and this is a helpful excuse).

Lots of bad advice.  “Get out of the building!” Um, no, probably a bad idea in a land of modern office towers where the greatest risk isn’t the building falling, it is window panes popping out and flying down to earth. Better to stay inside. [An aside: is it possible to hit a resonance with a tower that would launch office furniture through the windows? Kind of wonder a little]. “We need to get out of the Bay” as the tsunami (itself hopelessly unlikely) roars towards the Golden Gate.  Better to sit out in the interior of the bay as the water spreads out. And how does the big container ship come over the crest of the tsunami at the speedboat? It would mean that the ship was moving rapidly towards San Francisco, but we see that it was aimed out to sea. At least we did get the “Drop, cover and hold on” advice, which is fairly accurate.

Of course, as many have noted, you wouldn’t get a big tsunami from a San Andreas earthquake; your best hope would be from a major submarine landslide associated with the quake, and even then the size of the tsunami shown is extreme. Its behavior is also a bit off (look at the video from the Tohoku earthquake if you want a sense of what things might look like–also just how much of a mess that water would be).

And of course at the end, our hero promises to rebuild.  One would hope not with any of the architects that managed to make stuff as vulnerable as shown here…

On the last shot, as we pull back in an aerial view, look and see what has become of the South Bay–it is now gone underwater.  No more Silicon Valley!  You kind of wonder if that is more of an in-joke…

Anyways, not a primer in earthquake science, but that is hardly a surprise.  Lots of detail in destroying lots of iconic landscapes.

GG’s daughter asked, “So is it worse that The Core?” And the answer is no, but it is in the conversation.


5 responses to “So how bad is “San Andreas”?”

  1. Bruce Haddow says :

    Any comments on the movie “Letter Never Sent”, 1960, Mikhail Kalatozof director. A 7.9 rating on IMDB, haven’t read any geologists’ reviews yet.


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