How Realistic Is The Disaster Movie San Andreas?

San Andreas starring Dwayne ‘The Rock’ Johnson is a hit. The official movie trailer is on YouTube, and the movie opens nationwide this weekend. The plot revolves around a mega-earthquake in California, affecting the whole state, along the San Andreas fault. “In the aftermath of a massive earthquake in California, a rescue-chopper pilot makes a dangerous journey across the state in order to rescue his daughter.” Sounds fairly entertaining. But how realistic is it? [Mild plot spoilers follows. You have been mildly cautioned.]

First, take a look at this intriguing post at Gizmodo. They quote USGS seismologist Dr. Lucy Jones in her evaluation of the movie. There’s the usual movie foolishness of people seeming like they can outrun things, like a dam collapsing. [Other movies and TV shows have people outrunning explosions, cars, trains, etc.] She also points out that a San Andreas quake wouldn’t cause a tsunami. That would be caused by a quake located under the ocean.

Dr. Jones also points out an exaggeration in the movie. Even in a more powerful quake, not every building will collapse. She estimates one in 16 buildings would collapse. The movie predictably exaggerates the damage to buildings.

The movie did get some things right, including that a large earthquake can trigger subsequent quakes and that a tsunami is sometimes preceded by a withdrawal of the water out to sea. Another good point: the movie shows some people reacting properly to the quake: drop, cover, and hold on to something.

Here’s a more thorough evaluation of the facts and myths found in the San Andreas movie, presented by the Earthquake Country Alliance. Is a 9.6 level quake possible in CA? They say: “The fictional magnitude 9.6 that devastates San Francisco would be 90 times more intense overall than the largest earthquake possible (“only” a magnitude 8.3) on the San Andreas fault!”

I found this scientific description of the effects of an earthquake interesting: “For the of magnitude 9.1 and 9.6, earthquakes in the movie, the actual shaking shown is over far too soon (it should last 6-10 minutes), and doesn’t shake strongly enough (people can walk, run, and drive). The shaking also does not depict how earthquakes typically have an initial sharp jolt and then are followed a few seconds (possibly up to 30 seconds) later by more violent shaking.” So for a very strong quake, you would not be able to walk, run, or drive a car effectively. This is why you “drop” to the floor or ground when an earthquake begins.

Best advice during an earthquake: Drop, Cover, Hold.

“In MOST situations, you will reduce your chance of injury if you:

DROP down onto your hands and knees (before the earthquakes knocks you down). This position protects you from falling but allows you to still move if necessary.
COVER your head and neck (and your entire body if possible) under a sturdy table or desk. If there is no shelter nearby, only then should you get down near an interior wall (or next to low-lying furniture that won’t fall on you), and cover your head and neck with your arms and hands.
HOLD ON to your shelter (or to your head and neck) until the shaking stops. Be prepared to move with your shelter if the shaking shifts it around.”

If you live in an earthquake prone area, you might want to locate the best places in your home to find COVER, like a very sturdy table. If you don’t own such a piece of furniture, consider buying or making one. It should be sturdy enough not to collapse if part of a wall or ceiling falls on it.

So, we all know that movies tend to exaggerate. And a disaster movie will predictably exaggerate the various aspects of the disaster. But be warned that one particular danger from earthquakes is often understated or ignored: massive fires in a city affected by the quake. “Fires following these earthquakes would be a much bigger and broader issue than shown in the movie. In the much smaller M7.8 “ShakeOut Scenario” earthquake scenario for southern California, more than 1600 fires are projected to start, some becoming superconflagrations.”

A super-conflagration occurs when multiple out-of-control fires merge and then spread rapidly. A moderately large quake in a CA city could start hundreds of fires, due to physical damage to buildings. If these fires merge, a firestorm develops. The rapidly rising hot air, over a very large area pulls in air from all sides, creating its own wind and feeding the fire. The result can be vast devastation and loss of life.

Some tips on safety after a large quake here.

– Thoreau

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