Catastrophic earthquake scenarios have played out on the
silver screen for decades, terrifying viewers with quakes
that can collapse skyscrapers or topple entire cities. Here's what will happen if the
big one hits the West Coast. On July 4, 2019, Ridgecrest, California, was hit with a 6.4 magnitude earthquake and then a 7.1 just one day later. But neither of these compare
to the long-awaited big one, which scientists predict will eventually rattle the golden coast. But when it hits, what will
that actually look like? Here's what experts say could happen in the seconds, hours, and
days after the big one. While experts can't know
exactly when a quake will occur, they have a pretty good idea of where. California is located in
a hot zone of fault lines, the most notorious of them
the San Andreas Fault. John Vidale: You know, here
in California you have dangers from a number of different
kinds of earthquakes. The major danger is from the earthquakes on the San Andreas Fault system. Narrator: On average,
the San Andreas Fault ruptures every 150 years. The southern parts of the
fault have remained inactive for over 200 years. Vidale: We haven't had a big earthquake in Southern California really since 1857. Narrator: In other words, we're
overdue for a major shake. According to a 2008 federal report, the most likely scenario
is a 7.8 magnitude quake that would rupture a 200-mile stretch along the southernmost part of the fault. Vidale: It's basically moving
the ground several yards over an area of 50 square miles. So the power of a magnitude 7.8 earthquake is probably close to the power used in the whole state for a year. Basically something that
we as a civilization have trouble creating, short
of, like, a nuclear explosion. Narrator: If you are near the
epicenter of the earthquake, it will be nearly impossible to stand. Vidale: People have this
idea of running out of bed, out of their buildings,
and that's a terrible idea, because a lot of what we
see in earthquakes is people with broken legs and people
who've run through glass. The best thing to do, like we always say, is duck, cover, and hold. Get under some piece of furniture. The main point is to
protect your head and chest. Narrator: During and immediately
following the shaking, buildings could collapse. John Wallace: The number of
buildings that were constructed before about 1980 is really significant, and most of these buildings are very vulnerable to
damage and collapse. Narrator: In this time-lapse video, you can see how building
components would hold up in a high-magnitude earthquake. Wallace: 'Cause the San
Andreas will produce the kind of long-period shaking which would be very damaging
to very tall buildings, say, in downtown LA, and Century City, and Long Beach, and so forth. Older steel buildings,
the connections in them have not necessarily been designed to withstand the maximum forces that actually can be generated. Narrator: Unreinforced
structures are the least stable, but even buildings up
to code could crumble. John Stewart: The building code, with its minimum requirements, does
not ensure that the building will be serviceable after an earthquake. It's intended to not kill anybody. There's a sense that if
it's modern, code-designed, it's earthquake-proof and
everything should be great, but that's not the reality. Narrator: Five steel high-rises could collapse completely, while 10 others will be red-tagged, or unsafe to enter. And, no, the quake would
not cause a tsunami, despite what movies
would have you believe. Vidale: To trigger a tsunami,
it takes an earthquake that moves the ocean floor, and most of the San Andreas is on land, so there would be a little
bit of waves generated from a San Andreas earthquake, but nothing that would be dangerous. Narrator: The quake could
kill about 1,800 people and leave 50,000 or more with injuries. While people could die from falling debris and collapsed structures, the highest death toll
would be from fires. Vidale: Historically, they biggest hazard from earthquakes has been fire. In the 1906 earthquake there
were 3,000 or 4,000 people who were just caught in that wave of fire that swept through the city. Narrator: The aftermath of the big one will wreak havoc on
infrastructure and the economy. Scott Brandenberg: Below our
streets and our buildings is this really complicated
network of infrastructure that could be damaged,
and a lot of the things we take for granted every day won't be available anymore, right? Like water, electricity, being able to drive
where you need to drive. Narrator: Parts of the San Andreas Fault intersect with 39 gas and oil pipelines. This could rupture
high-pressure gas lines, releasing gas into the air and igniting potentially
deadly explosions. Stewart: So, if you have
natural-gas lines that rupture, that's how you can get
fire and explosions. Narrator: And after the fires burn out, one of the biggest concerns
in a major earthquake is access to fresh water. The major aqueduct networks that pump water into Southern California all cross the San Andreas Fault and could be seriously damaged. Stewart: So we would be
without the lifelines that bring in imported
water to the region. They cross through tunnels, cross through aqueducts near the surface. All of these would be ruptured, and so we would be losing
60% of our water supply. Many of these distribution lines for water are near sewer lines,
which would also be broken, so now you have a situation
where contaminants are potentially getting
into the water supply. Narrator: Experts say you should keep at least a two-week supply
of water in your home. As the ground shakes and sediments shift, there will be landslides
throughout Ventura and Western Los Angeles County. Brandenberg: There could
be thousands of landslides. There have been earthquakes
that have produced thousands. Landslides definitely can cause
fatalities, property damage. We have a lot of people who
live up in the hills. Right? So that's the location
where you would be likely to see landslides affecting people. Narrator: And finally, the big one will severely impact the economy. Major transportation networks,
like highways and railways, could be unusable for
weeks and even months. Brandenberg: Some bridges
may not be passable after an earthquake. We've had bridges collapse
during past earthquakes. Stewart: You might start seeing key industries leave, population loss, and this could have, you know, devastating long-term
impacts for the region. Narrator: The estimated financial cost of the big one is a whopping $200 billion, with $33 billion in building damages and $50 billion in lost economic activity. This all sounds pretty
bad, but keep in mind that this is based off
of a worst-case scenario. The true impact of a major earthquake is based on a range of unknowable factors. Also, smaller earthquakes on faults directly beneath major population centers are a serious concern. Vidale: But the worst-case earthquakes are hard to predict. You know, that earthquake
in Japan in 2011, their cost almost entirely came because their nuclear
power plant melted down. It's very hard to
predict what's gonna fail in a big earthquake. Narrator: So, how can Californians prepare for the big one? Brandenberg: Really have a plan in place. You know, where are you going to meet? What are you going to do? Have water ready. I have a 55-gallon drum full of water. There's some chemical additive I put in it so it's potable for five years. Fifty-five gallons is the
right amount for my... I have a family of four. That'll last us for two weeks. Canned food. You know, you have to be ready. I would say it's best just to plan to stay sort of where you are. Getting out of LA is bad enough without an earthquake, right? Traffic's already terrible. If roads are closed and people
are all trying to leave, it's gonna really be bad.
