- The Pacific Northwest is due for a major earthquake.
- These really dramatic events have happened in our past
and they will happen again.
- Tony Johnson is Chairman of the Chinook Indian Nation,
one of the Indigenous communities
already preparing for the next "Big One."
- You know, we spent a lot of time worrying
about what's that going to look like?
It's a really grave concern for us.
- We really need to be prepared for that eventuality
because it's not a matter of if,
it's just a matter of when.
(dramatic music)
- These days,
it may seem like earthquakes are not all that uncommon
due to frequent media reports...
- Breaking news just into CNN,
a very strong earthquake just minutes ago...
- And lots of cell phone videos posted online.
But it's actually been centuries since the contiguous U.S.
last experienced a truly "Big One,"
an earthquake with a magnitude greater than eight.
The last one on record was the earthquake of 1700
with an estimated magnitude of nine.
So, what caused this earthquake?
- The biggest earthquakes in the world
are along subduction zone boundaries.
And those are places where one tectonic plate
is diving down underneath another tectonic plate.
The largest earthquake that's happened in the U.S.
that we're aware of
was along the Cascadia Subduction Zone
where the Juan de Fuca Plate
is diving down underneath the North American Plate.
And we can get really big earthquakes there
because the plate that's going down
is usually oceanic crust,
which is cold and dense,
that means it can break.
So if you think about baking chocolate chip cookies,
when you pull the cookies right out of the oven,
they bend and they're nice and gooey,
but once they've gotten to be cold, they break.
So that cold dense crust that's going down
can break for a much longer time.
So we get bigger earthquakes in those particular places.
- The same tectonic activity that caused the earthquakes
resulted in another destructive event-- a tsunami.
- You have one plate diving down beneath another.
This section gets locked and it pushes this part up.
When the fault ruptures,
when the amount of stress overcomes the friction,
it bounces back,
which lifts up the water above it
and causes that water to flow out in all directions.
And that water flowing out in all directions is the tsunami.
- Clues about the earthquake and tsunami of 1700
can be found in these eerie looking ghost forests.
- And we have evidence of these submerged trees
or the ghost forests in numerous places around our area,
including at our traditional village.
- These ghost forests formed
when the area became submerged
after being hit by the tsunami.
Even after the tsunami receded,
the entire landscape had actually dropped several feet,
a result of the plate tectonic motion.
Oral histories of the event
suggest that many died in the tsunami.
And Heritage and Cultural Director
of the Shoalwater Bay Tribe, Earl Davis,
explains how additional clues
about life after this earthquake and tsunami
were pieced together.
- The archaeological record basically suggests
that tsunami came,
laid down a bunch of sand,
and then people went back to kind of normal life.
You can see it right in the soil.
There's a layer of just sterile sand
and then there's an occupation layer immediately after it.
It doesn't appear like there was a huge rebuilding time
for us back then.
- For communities along the coast at sea level,
an earthquake and tsunami event
could have a much bigger impact today than it did in 1700.
- Our lifestyle now
is largely predicated on the modern Western
colonialized-type lifestyle
of putting in a cement foundation
and running all these utilities
and building a big, expensive infrastructure
that is supposed to be there for
200 or 300 years.
Whereas traditionally speaking,
we put some poles in the ground,
covered them in planks,
lived there for half the year,
then packed up all the planks
and went to where we had another house,
maybe up to 100 miles away to better fishing grounds
or better grounds for avoiding harsher weather.
- And the threat of another event like this is very real.
- The geologic record tells us
that there are large earthquakes along that boundary
about every 300 to 500 years.
- Which means we could be getting close to another "Big One"
The Shoalwater Bay Tribe
applied for and received federal funding
to construct a tsunami evacuation tower
on their reservation,
a structure that could protect
the most vulnerable populations
by providing quick access to higher ground.
- The driving force behind the tsunami tower
is giving a place down there
a fighting chance of getting up above that wave.
- When completed,
the tsunami tower will be only the second in the country.
However, other Indigenous communities
that the U.S. government has failed to recognize
don't have access to the same federal resources,
like the Chinook Indian Nation
that Tony Johnson's a member of.
- We have the great benefit
of continuing to reside on our Aboriginal lands
and we have the horrible reality
of not being truly federally recognized
as an Indian community.
And with that federal recognition
comes so much of the support that we need.
You know, we have a goal or at least an initial thought
of building two tsunami evacuation towers,
but don't have access to the resources
that our federally recognized neighbors have.
I don't think it is very likely
that anybody will leave the village
after a nine point earthquake.
There's a bridge to the landform that most folks live on
and I can't imagine that bridge surviving that earthquake.
So it really will be that folks on the island itself
are going to either be high enough or not.
(somber music)