scientists say earthquake early warning
system worked in 5.3 tremor
Caltech and the USGS are developing Shake
Alert, which will provide west coast
residents with early warnings for
LOS ANGELES, CA (California Network) -
Engineers from Caltech and the U.S.
Geological Survey announced that their
earthquake early warning system, "shake
alert" worked well during yesterday's quake.
The quake was a 5.3 magnitude event and
no damage or injuries were reported, aside
from a few bricks falling off a chimney on
Santa Cruz Island. The quake was centered
offshore, about 41 miles away from the
coastal city of Ventura and just off the
south coast of Santa Cruz Island. The
shaking was felt as far north as Bakersfield
and San Luis Obispo, and as far south as San
Diego. It was also felt in parts of Los
Angeles, especially near the coast.
The quake was an event of moderate
intensity and had it occurred in Los
Angeles, it might have done some light
damage or caused injuries. Most So Cal
residents would shrug off such a quake,
except the region has been in an "earthquake
drought," a period of seismic calm. The last
similar quake was in 2014. That calm can
USGS and Caltech engineers are working on
an early warning system that uses sensors
across the state to detect the first waves
of an earthquake and send a warning to
phones via a special app. Similar systems
are already in use in Japan and Mexico. A
struggle for funding has resulted in the
program taking more than 12 years so far in
California. The system is about 50 percent
complete, with upgrades due to more than 200
seismic monitoring stations. Funding to
complete the project has been allocated in
the state budget and the system will be
available for the public in about 4-5 years.
In the meantime, the system is being
beta-tested and some schools and critical
infrastructure may get it much sooner than
the general public.
The system works by detecting shaking and
by triangulating the origin of the event. It
then measures the intensity of the shaking
and based on models, anticipates how far
away the shaking should be felt. Finally, it
generates an alert which sounds on the
phones of people with the app installed.
Because it is computer-driven, this process
can happen almost instantly.
Such a system can provide seconds of
valuable warning time, up to a
minute-and-a-half in some cases.
At Caltech, engineers announced they had
about 10 seconds warning before they felt
Ten seconds may not seem like a lot of
time, but it is enough to stop trains and
traffic and to warn people to take cover.
Combined with training, such a system can
Earthquakes always take people by
surprise. Shaking is usually gentle at
first, then there is a large jolt, and
shaking intensifies. The correct response is
to take cover at the first sign of shaking,
but many people instinctively run outdoors.
This can be dangerous because as the shaking
intensifies, roofing material, glass, and
facades can fall, striking people just as
they exit the structure.
An early warning might give some lucky
people a chance to get to safety before
shaking starts. For those inside, it will
give them a few seconds to consider a safe
response and to take adequate cover. Instead
of crouching under the first desk or chair
they find, they may have more time to seek
shelter under a sturdier table.
Most quakes last only a matter of
seconds, usually about ten to fifteen.
However, some can last upwards of a minute
or more and those are much more damaging.
Quakes can also be frightening because
everything moves, even things people would
never expect to move, such as sturdy
furniture. Everything makes noise and
buildings creak. Seconds after the quake
begins, shaking can intensify, which can
It is hoped the system will be functional
by 2019 and will begin to protect schools
and public infrastructure at that time. It
cannot come too soon, for geologists predict
the state is overdue for a major quake on
the San Andreas fault, although this is an
inexact science. A major quake, while likely
to occur sooner than later, may not happen
for decades or more. But the safe approach
is best, and the state is scrambling to
deploy its early warning system before
nature does her worst. Yesterday's event was
just a reminder of what can happen anywhere
in the state, at any time.