Earthquake Early Warning (EEW)
Understanding how earthquake early warning systems work and how Grillo enables this technology.
What is earthquake early warning?
Earthquake Early Warning (EEW) systems detect earthquakes and send alerts before strong shaking arrives at a location.
This is possible because:
- Electronic signals travel faster than seismic waves
- P-waves (faster, weaker) arrive before S-waves (slower, stronger)
- Warning time increases with distance from earthquake
How EEW works
The physics
Earthquake occurs
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P-waves radiate outward (faster, ~6 km/s)
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Sensors detect P-waves
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System calculates location & magnitude
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Alerts sent electronically (speed of light)
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People/systems receive warning
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S-waves arrive (slower, ~3.5 km/s, stronger shaking)
Warning time
The warning time depends on:
| Factor | Effect |
|---|---|
| Distance from earthquake | More distance = more time |
| Network density | Denser = faster detection |
| Processing speed | Faster = more warning |
| Alert delivery | Electronic = nearly instant |
Typical warning times
| Distance from epicenter | Approximate warning |
|---|---|
| 10 km | 0-5 seconds |
| 30 km | 5-15 seconds |
| 50 km | 10-20 seconds |
| 100 km | 20-40 seconds |
note
Areas very close to the earthquake may receive no warning before strong shaking.
What can you do with seconds?
Personal safety
Even a few seconds allows:
- Drop, Cover, Hold On
- Move away from hazards
- Alert others
- Mental preparation
Automatic actions
Systems can automatically:
- Stop elevators at nearest floor
- Open fire station doors
- Slow or stop trains
- Shut off gas valves
- Save computer data
- Initiate safe shutdown procedures
Every second counts
Studies show significant benefits:
- Reduced injuries from falling objects
- Faster emergency response
- Less secondary damage (fires, etc.)
- Better psychological outcomes
EEW components
Detection network
Dense seismic sensor network:
- Detects P-waves quickly
- Multiple stations confirm
- Covers area of interest
Processing system
Central system that:
- Receives sensor data
- Detects earthquakes
- Calculates parameters
- Generates alerts
Alert distribution
Methods to reach people:
- Smartphone apps
- Sirens
- Broadcast alerts
- Direct system integration
Grillo and EEW
Enabling affordable EEW
Grillo makes EEW accessible by:
- Lowering sensor costs
- Simplifying deployment
- Providing cloud processing
- Enabling alert distribution
Building EEW networks
With Grillo you can:
- Deploy dense sensor networks
- Enable automatic detection
- Configure alert rules
- Integrate with response systems
Requirements for EEW
| Requirement | Grillo solution |
|---|---|
| Dense sensors | Affordable Grillo sensors |
| Fast detection | Grillo Cloud processing |
| Alert delivery | Webhook/API integration |
| Reliability | Cloud infrastructure |
EEW limitations
No warning near epicenter
Very close to the earthquake:
- S-waves arrive almost immediately
- Not enough time for detection and alert
- "Blind zone" near epicenter
Not earthquake prediction
EEW is not prediction:
- Cannot predict earthquakes before they occur
- Only warns after earthquake starts
- Based on detected waves, not forecasts
Dependent on network
Warning quality depends on:
- Network coverage
- Sensor density
- System reliability
- Alert delivery speed
False alerts possible
Systems may:
- Trigger on non-earthquake signals
- Have incorrect initial estimates
- Update parameters as data arrives
Global EEW systems
Operational systems
| System | Region | Since |
|---|---|---|
| JMA | Japan | 2007 |
| ShakeAlert | US West Coast | 2019 |
| SASMEX | Mexico | 1991 |
| Various | Taiwan, South Korea, others | Various |
Grillo contributions
Grillo technology supports EEW in:
- Mexico (school networks)
- Chile (community networks)
- Various research deployments
Implementing EEW with Grillo
Step 1: Build your network
- Deploy Grillo sensors across your area
- Ensure adequate density (varies by goal)
- Maintain high online percentage
Step 2: Enable detection
- Subscribe to Events feature
- Configure detection parameters
- Validate detection performance
Step 3: Set up alerts
- Configure alert thresholds
- Set up delivery channels
- Test alert delivery
Step 4: Integrate systems
- Connect to building systems
- Develop response procedures
- Train occupants/staff
Step 5: Maintain and improve
- Monitor system performance
- Address issues promptly
- Expand coverage over time