Sensor Placement Best Practices
Proper sensor placement is crucial for data quality and network effectiveness.
Why placement matters
Sensor placement affects:
- Signal quality - Good placement captures earthquakes clearly
- Noise levels - Poor placement adds unwanted signals
- Detection capability - Position affects what you can detect
- Data usefulness - Scientific value depends on installation
Site selection principles
Ideal characteristics
The best sensor locations have:
| Characteristic | Why it matters |
|---|---|
| Solid foundation | Better coupling to ground motion |
| Low noise | Cleaner seismic signals |
| Stable environment | Consistent data quality |
| Reliable power | Continuous operation |
| Network connectivity | Real-time data transmission |
Location hierarchy
From best to acceptable:
- Bedrock - Lowest noise, best coupling
- Concrete slab on grade - Very good
- Solid floor (ground level) - Good
- Upper floors - Acceptable with considerations
- Loose/soft surface - Avoid if possible
Floor selection
Ground floor recommended
Ground floor or basement is ideal:
- Closest to actual ground motion
- Less building amplification
- More representative data
Upper floor considerations
If upper floors are necessary:
- Data affected by building response
- Amplification at certain frequencies
- Still useful for many applications
- Document floor level in metadata
Foundation types
Concrete slab
Best common foundation:
- Direct coupling to ground
- Stable platform
- Low local noise
Installation: Place directly on clean concrete.
Raised floor
Common in offices/data centers:
- Avoid if possible
- If necessary, extend mount to slab below
- Document installation type
Carpet/soft flooring
Problematic surface:
- Damping affects high frequencies
- Sensor may shift
- Consider rigid platform underneath
Distance from noise sources
Sources to avoid
| Source | Minimum distance | Notes |
|---|---|---|
| HVAC equipment | 3+ meters | Continuous vibration |
| Elevators | 5+ meters | Intermittent noise |
| Heavy machinery | 10+ meters | Depends on machine |
| Major roads | 20+ meters | Traffic vibration |
| Rail lines | 50+ meters | Significant noise |
Indoor noise sources
- Air handling units
- Generators
- Pumps and compressors
- Large motors
- Server rooms (fans)
Outdoor considerations
- Vehicle traffic
- Construction
- Industrial activity
- Railways
- Aircraft (near airports)
Orientation and leveling
Proper orientation
For accurate directional data:
- Note sensor orientation marking
- Align to north if specified
- Document actual orientation
- Consistent across network helps
Leveling
Critical for data quality:
- Use a bubble level
- Sensor must be horizontal
- Adjust mounting as needed
- Re-check periodically
Stability
Prevent movement:
- Secure mounting
- Anti-slip surface/pads
- No wobble when touched
- Won't shift over time
Installation environments
Office buildings
Good locations:
- Ground floor, away from HVAC
- Utility rooms with solid floors
- Storage areas (if stable)
Avoid:
- Near elevator shafts
- HVAC mechanical rooms
- Floors with heavy foot traffic
Schools
Good locations:
- Basement if available
- Ground floor storage/utility
- Science labs (stable tables)
Avoid:
- Gymnasiums (activity)
- Music rooms (vibration)
- Near playground equipment
Residential
Good locations:
- Basement floor
- Ground floor closet
- Garage slab
Avoid:
- Near washing machines
- Near HVAC equipment
- Upper floors if possible
Industrial facilities
Good locations:
- Office areas away from production
- Utility buildings
- Perimeter locations
Avoid:
- Production floors
- Near heavy equipment
- High-vibration areas
Outdoor installations (Grillo Pulse)
Ground installations
- Concrete pad or bedrock
- Away from trees (root movement)
- Good drainage
- Clear of flood zones
Pole mounting
- Sturdy pole/post
- Minimal flex in wind
- Low as practical
- Proper leveling
Environmental protection
- Shade from direct sun
- Protection from extreme weather
- Away from sprinklers
- Secure from animals
Common mistakes
Poor site selection
| Mistake | Problem | Solution |
|---|---|---|
| Near HVAC | Constant noise | Relocate away |
| On carpet | Damping/instability | Use rigid base |
| Upper floor | Building effects | Move to ground floor |
| Near traffic | Traffic noise | Increase distance |
Installation errors
| Mistake | Problem | Solution |
|---|---|---|
| Not level | Incorrect data | Re-level sensor |
| Loose mounting | Sensor moves | Secure properly |
| Cable tension | May shift sensor | Allow cable slack |
| Poor coupling | Weak signals | Direct floor contact |
Verification
After installation
Check:
- Sensor is level
- Mounting is secure
- No wobble or movement
- Away from noise sources
- Power and network stable
- Data quality looks good
Periodic checks
Review regularly:
- Physical stability
- Changed noise sources
- Data quality trends
- Environmental changes
Documentation
Record for each sensor:
- Exact location (coordinates)
- Floor/level
- Surface type
- Nearby equipment
- Installation date
- Photos