(dramatic music)
These two pieces of UC
Berkeley's Memorial Stadium
used to be lined up.
One of California's
most treacherous faults
runs right through this campus
as well as near cities
like San Jose and Oakland,
which are epicenters for tech innovation
and economic output.
You normally can't see it or feel it,
but the ground here is always shifting.
The energy released from this fault
has culminated in a big earthquake
on average once every 140 years.
The last one was roughly 150 years ago.
We may now be on borrowed time,
so what can be done to
protect us from the big one?
- We can actually see here
that the building is designed
to accommodate the movement of the fault.
So we can see one side, it's
moving past the other side
as the fault slips.
- So we know that there's
movement of the earth.
Can we predict when an
earthquake is going to happen?
- Unfortunately, no, there's no evidence
that we can predict earthquakes reliably.
The thing that we have at the moment
is a quick early warning,
and that can tell you
that an earthquake has happened
and that you're about to feel shaking.
- [Daniela] The shaking is
caused by waves that travel
through the earth's crust
like ripples on a lake,
and it's those ripples that the sensors
of an earthquake early
warning system detect.
- Some of the most notable
earthquake early warning systems
are the ones in Japan and
the ones in Mexico City.
(engine rumbles)
- Mexico City's earthquake alert system,
called SASMEX, was created in response
to the devastating earthquake of 1985
that killed more than 6,000 people.
Alerts have been available to residents
in a portion of central
and southern Mexico
for more than 20 years.
(sensor beeps)
When a major earthquake is detected,
the public is alerted via TV or radio
or one of the municipal speakers
like the one across the street behind me.
But all of them don't always work.
- This was the first building that I saw
that had been damaged by the earthquake.
- [Daniela] In 2017, Wall Street Journal
Mexico City Correspondent Robbie Whelan
lived through two earthquakes
that were just 12 days apart.
The second devastated
the nation's capital.
Did you hear the alarm in your office?
- I did not, no.
It was a total surprise.
I was walking in the sidewalk,
and suddenly, the sidewalk was moving.
There used to be a seven or eight story
office building here, a
medium-size office building
with a lot of different
businesses located in it.
Several floors had really pancaked
from being about seven or eight feet tall
to being about one or two feet tall,
so it became immediately clear
that it was gonna be very hard
for a lot of the people in
the building to get out.
At the end of the day,
I think 49 people died in
this building site collapse.
- There was an earthquake a
couple weeks before, right?
What was that one like?
- It was felt in Mexico City,
but it wasn't nearly as strong.
- And did the alarm system work
in either of those situations?
What was that like?
- In the earlier earthquake,
citizens of Mexico City had something like
a minute and a half or two
minutes of advance warning
that the earthquake was coming.
The second earthquake,
the early warning system
was not as effective.
I think there was a few seconds of warning
for most people in the city.
- When earthquakes are close,
you have very little time.
- Professor Gerardo Suarez
of the SASMEX Research
and Development Team
has been studying Mexico
City's seismological activity
for the past three decades.
Distance is really key to
being able to alert people.
Are there things you
can do with the sensors
that would help minimize that distance?
- Yes, we try to make the algorithms
to work as fast as possible.
It's a catch-22 situation.
You want the algorithms to very quickly
identify it in the seismic waves
that it's detecting to say yes,
it's a large earthquake, it's a go.
But on the other hand,
you want to be careful
because, then, you cry wolf very often
with the small earthquakes and
you have to be very careful
of not issuing false alerts.
- Back in the US, the team
at UC Berkeley seismology lab
is helping develop ShakeAlert,
the country's first early
earthquake warning system.
They've been researching earthquakes
for more than 100 years.
Some of their findings were used
to develop the system in Mexico,
which currently only
has about 100 sensors.
ShakeAlert already has
roughly 1,000 sensors
along the West Coast.
Earthquake detection hinges on data.
In theory, the more
sensors, the more data,
which should translate into earlier
and more reliable earthquake warnings.
How accurate is ShakeAlert?
- With the largest magnitude events,
it's very difficult to estimate
exactly how big it will be,
so I will certainly not
say that we will get
a magnitude 7.6 earthquake
right on the button.
- [Daniela] Towing the line
between not crying wolf
but still alerting users
of noticeable shaking
can be difficult.
The ShakeAlert team got a lesson
in balancing these two opposing
needs earlier this year.
Two strong earthquakes
hit Southern California,
but the LA pilot app
failed to notify users
that either were coming.
- And the reason behind that
is because neither of them
surpassed both the magnitude
and the intensity thresholds.
With the first earthquake,
the magnitude 6.4 earthquake,
ShakeAlert actually did a pretty good job
with estimating the location
and the magnitude of the earthquake.
The predicted shaking
in LA wasn't high enough
to surpass the intensity
shaking threshold,
and that's why no alert
was sent for that one.
With the second larger
earthquake, the magnitude 7.1,
our system did actually
underestimate the magnitude
a little bit.
- [Daniela] Now, they're
using what they've learned
from the LA pilot program
to prepare for the Bay
Area's ShakeAlert system.
- These really large earthquakes,
they take time to rupture,
so if an earthquake is still happening,
because it takes eight seconds to rupture
and we're only using three
or four seconds of data,
we actually don't know
that it's gonna get bigger,
so we need to try and adjust
our algorithms a little bit
to try and make sure that
we're really capturing
the size of these really
large earthquakes.
If it were to happen again today,
the system would already perform better
because of these things
that we've learned.
- The US system is
aiming for cell carriers
to transmit earthquake alerts
similar to how we get AMBER alerts.
Are there any technological roadblocks
to getting the message on a
cellphone to users quickly?
- If you have a lot of people
that you're trying to send a message to
in a very short amount of time
from a single cellphone tower,
it can kind of create a
bit of a blockage there,
and so trying to get the alert out
to lots of people at one time
is definitely a challenge.
- 'Cause as you said,
every second matters,
right?
- Every second matters.
So if there's a 15 second delay,
that's not gonna be terrible useful
for people who are right
next to the earthquake.
- [Daniela] Right now,
there are pilot programs
for the ShakeAlert app in
portions of California, Oregon,
and Washington.
In addition to the mobile
alert style notifications
from ShakeAlert, there's also
talk of creating hardware
similar to a home smoke alarm
or a carbon monoxide detector,
but for earthquakes.
This one (detector beeps) was created
by Mexican startup Grillo.
No matter what, early
earthquake warning systems
are not a replacement for preparations
like an emergency supply
kit and a safety plan.
The best case scenario is
giving people enough warning
to duck and cover in the final moments
before the big one hits.
(soft dramatic music)
