Earthquakes are unpredictable and can strike with enough force to bring buildings down. Find out what causes earthquakes, why they're so deadly, and what's being done to help buildings sustain their hits.
Transcript
The ground starts to
quiver…
Glasses rattle…
Soon walls shift and
everything begins to collapse – telltale signs of what could be a devastating
earthquake.
We’ve
seen the destruction they unleash. Some of us may have even lived through one.
And we know they can be deadly.
But
where does this mountain-moving force come from?
This is Earthquakes 101
On average, earthquakes
kill about 10,000
people each year.
Sometimes numbers are far higher.
The quake that hit Haiti in 2010 killed more than 300,000 by some counts —
making it one of the deadliest on record.
While we may think we’re standing on solid ground, the earth
beneath us isn’t completely stable at all.
Our planet’s crust is
made up of about 12 major tectonic
plates that fit together
like a giant jigsaw puzzle.
These huge slabs of land float on super-heated
magma and
constantly shift, bump, and grind against one another. It’s there, along the
seams, where earthquakes tend to happen.
When friction between two plates is violent
enough, seismic shock waves ripple through the ground, rattling everything
that stands on it.
The stronger and shallower the quake, the more violent the destruction.
Every year, about 100,000
earthquakes
rumble through the ground and shake hard enough for people to feel them.
Of these, only about .1
percent are strong enough to cause significant damage.
The
magnitude of an earthquake is measured using the RichterRichterscale which runs from 0 to 10 - 10 being the strongest. Every whole number
increase on the scale means 10 times more ground motion change - that’s a LOT!
In recorded history,
the world has never experienced a 10 on the Richter Scale, but scientists
predict an average of at least one major quake of magnitude 8 or higher every
year.
The of earthquake is born in a subduction zone,
where one tectonic plate is shoved beneath another. While one plate is forced downward into the
mantledownward into the
mantle
the other juts upward, often violently. This is the type of quake that rocked
Nepal in May 2015.
And when subduction
happens on the sea floor, it can create giant unstoppable
waves, called tsunamis, like the ones that killed hundreds of thousands in Japan
and Indonesia…
The fact is, the earth’s crust is restless and always on the
move. We can’t see earthquakes coming... but we can prepare for them.
Engineers are now
designing stronger buildings, resilient enough to survive a direct hit.
Scientists are
crunching data to project the power of future quakes and anticipate when and
where they could strike next.
Right now, we can only
estimate the probability an earthquake will occur. But perhaps one
day, we will learn to predict them... minimizing their destruction, and
saving countless lives.
