You're on a beach.
Not a worry in the world.
The sun bronzing your skin,
sand trickling between your toes,
the sound of waves...
wait, what?
Better act quickly; in a matter of minutes,
you may be underwater.
Here's how to survive a tsunami,
Tsunamis are triggered by intense underwater activity,
usually an earthquake, or an underwater volcanic eruption.
These events displace huge volumes of water,
pushing it up from the ocean's floor to its surface.
But when gravity pulls it back down,
all this built up energy is released outwards,
forming deadly waves that grow stronger
as they ripple across the ocean.
A tsunami's waves can be 100 km (62 miles) long,
and sometimes taller than 30 meters (100 ft)!
They can travel across whole oceans,
moving at the speed of a jet airplane.
Even in a tsunami hazard zone, you can still survive,
if you know what to do.
The Pacific ocean is home to volatile tectonic activity,
In most cases, an earthquake comes before a tsunami.
So if you're near the coast, and you experience an earthquake,
protect yourself from that first.
But once the shaking stops,
move to higher ground as quickly as possible.
An early sign of an impending tsunami is that water along the coast will recede.
It pulls back and exposes the sea floor.
You'll only be putting yourself at risk for when the water surges back.
Instead, head in the opposite direction.
Try to get as far as 3.5 km (2 miles) from the ocean,
or 30 metres (100 feet) above sea level to ensure your safety.
Tsunamis travel quickly,
and you may not have enough time to clear the hazard zone.
In this case, look for a tall building, with a sturdy concrete foundation.
If you see one nearby,
run inside and get to the roof as quickly as possible.
If you can't make it to a building in time,
Though that might not sound very practical,
hold the eye-roll for a moment.
In the 2004 Indian Ocean tsunami,
an Indonesian woman was finally rescued
after holding onto a palm tree for 5 days straight.
While it isn't ideal, if you can't get to higher ground in time,
you need to find something to hold on to.
As the tsunami moves inland, it will sweep tons of debris along with it.
This can be very dangerous,
as the accumulation of debris, traveling at high speeds,
become fatal obstacles for anyone who's been caught in the current.
However, many tsunami victims have been saved
by climbing onto detached roofs
or holding on tightly to floating cars or other large objects.
A tsunami isn't one wave, but a series of waves,
known as a tsunami wave train.
Waves may be anywhere from 5 minutes apart, to an hour apart.
And be aware that the first wave that hits isn't always the strongest.
So even when you think it's over,
stay where you're safe until you hear from local officials.
It goes without saying, tsunamis are terrifying.
And when a 30 meter (100 ft) wave is hurtling towards you
at 800 km an hour (500 mph),
you're probably feeling pretty helpless.
But, have faith in science, trust empirical research,
and you'll see there's always a way out.
We'll keep showing you, one episode at a time,
on According to Science.