Table 2 Volcanic ash-induced damage to structures matrix (modified after Daly and Wilkie, 1999 )
From: The genesis of volcanic risk assessment for the Auckland engineering lifelines project: 1996–2000
Structure | Ash thickness <1 mm | Ash thickness 1-5 mm | Ash thickness 5 - 100 mm | Ash thickness >100 mm |
|---|---|---|---|---|
Pipework | ||||
Open systems (ie stormwater) | Low probability | High probability | High probability | High probability |
Closed systems | Negligible | Negligible | Negligible | Negligible |
Building structures | ||||
Flat-roof | Low probability | Mod. probability | High probability | High probability |
Pitched-roofs (>20°) | Low probability | Mod. probability | High probability | High probability |
Building services | ||||
Air-conditioning | Low probability | Mod. probability | High probability | High probability |
Gutters | Low probability | Mod. probability | High probability | High probability |
Electricity services | ||||
Power lines | Negligible | Low probability | Mod. probability | High probability |
Power line insulators: | ||||
Low voltage | Negligible | Mod. probability | High probability | High probability |
High voltage | Negligible | Low probability | Mod. probability | High probability |
Substations | Negligible | Mod. probability | High probability | High probability |
Civil structures | ||||
Roads | Low probability | High probability | High probability | High probability |
Rail | Negligible | Mod. probability | High probability | High probability |
Wastewater | ||||
Sewage pumps | Low probability | High probability | High probability | High probability |
Sewage treatment plant | Low probability | Mod. probability | High probability | High probability |
Water Supply Systems | ||||
River/Stream | Low probability | High probability | High probability | High probability |
Uncovered reservoir | Low probability | Mod. probability | High probability | High probability |
Cover reservoir/ground water | Negligible | Negligible | Negligible | Negligible |
Roof-fed tank | Low probability | High probability | High probability | High probability |
Telecommunications | ||||
Lines | Negligible | Low probability | Mod. probability | High probability |
Microwave towers | Low probability | Mod. probability | Mod. probability | High probability |
Exchange equipment: | ||||
External air-conditioning | Low probability | High probability | High probability | High probability |
Internal Air-conditioning | Negligible | Low probability | Low probability | Low probability |
Specific infrastructure | ||||
Ports | Low probability | High probability | High probability | High probability |
Airports: Air transport | Mod. probability | High probability | High probability | High probability |