((PKG))  SHAKE ALERT SYSTEM   
((VOA Persian)) 
((Banner:  Shake Alert)) 
((Reporter:  Crystal Dilworth))
((Camera:  Austin Harris, Kelly Butler))  
((Adapted by:  Martin Secrest)) 
((Map:  Pasadena, California)) 
((Main characters:  1 female;  2 males))  
((NATS)) 
((Pop-Up Banner:  California’s ‘ShakeAlert’ earthquake 
warning system uses in-ground and surface sensors)) 
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((Locater:  San Andreas Fault near Los Angeles, California)) 
((Elizabeth Cochran, Seismologist, US Geological 
Service)) 
So, both along the fault, we like those sensors really close 
the fault because that gives us really those first motions that 
are coming out of the earthquake.  It tells us the earthquake 
has started.  So, once that earthquake started, seismic waves 
start travelling away from where that earthquake starts.  ‘P 
waves’ or primary waves are the first waves that arrive.  
They’re faster and you feel sort of a jolt coming up beneath 
you. The ‘S waves’ would travel along behind those and start 
shaking you back and forth.  
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((Locater:  In-ground wave sensor site, Pasadena, 
California)) 
((Robert Michael De Groot, ShakeAlert Coordinator, US 
Geological Service)) 
So, we’re in Pasadena and we’re at one of the seismic 
stations.  At the bottom of this vault, this is what it is.  So, and 
it moves relative to the earth and basically whatever happens 
in here, gets turned into an electrical signal and boom.  It 
takes some very, very precise observation about what’s 
happening. 
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((Dave Sotero, Communications Manager, Los Angeles 
Metro Rail)) 
Well, we were one of the early adopters of the ShakeAlert 
system.  We implemented it in January of 2017 and it gives 
us precious seconds to anticipate an earthquake that may be 
coming to (the) Los Angeles area and that will enable us to 
put an alert out to our operators.  Part of the protocol is to 
slow down the train as it is moving in advance of an 
earthquake.  So, the slower you’re moving, the more safely 
you can operate the vehicle and stopping the vehicle is the 
best course of action for a large scale event. 
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((Robert Michael De Groot, ShakeAlert Coordinator, US 
Geological Service)) 
For very large earthquakes, the ShakeAlert early warning 
system is going to use seismometers,  
((Pop-Up Banner:  GPS stations)) 
but with the really big earthquakes, we’re going to need 
information from these stations because what’s going to 
happen is that if there’s a really big earthquake, these 
stations are going to move very quickly in a very short 
amount of time.  And that information is critical to understand 
the biggest of earthquakes.  We’re talking (about) 
earthquakes that are magnitude 8 and above. 
((NATS)) 
((Pop-Up Banner:   Northeastern Japan. March 11, 2011. 
Magnitude 9.0 earthquake and tsunami)) 
((Robert Michael De Groot, ShakeAlert Coordinator, US 
Geological Service)) 
Big earthquakes in places like Iran and Indonesia and they 
could stand to have their own earthquake early warning 
systems and this has actually become a really interesting 
international community.  We’re all learning from each other.  
One thing we want to do and the big currency of ShakeAlert 
is time.  Time is really important to us.  Currently, the time that 
it takes to get messages out is taking way too long and we 
want to reduce what we call ‘latencies’ as much as possible.  
So, we’re working with a whole array of partners, the 
telecommunications industry.  We’re working with mass 
notification providers, to get those messages out as quickly 
as possible. 
((NATS))