Note: This VAL system is currently known only from alert levels issued in reports.
Agency: Tonga Geological Services (TGS)
Name: Terrestrial Color Code
The aviation VAL system can be found here and the maritime VAL system can be found here.
Elements of VAL system
| Domain | Terrestrial |
| Volcano | All |
| System range | 4-level scale |
| Lowest level | 1 |
| Highest level | 4 |
| Level name type | Color & Word |
| Level for lack/loss of monitoring | ? |
| Volcanic activity | ? |
| Hazards possible | ? |
| Locations affected | Yes |
| Potential impacts | ? |
| Forecast language | ? |
| Timing language | ? |
| Actions to take | ? |
| Agency actions | ? |
| Link to evacuations | ? |
| Reporting frequency per level | ? |
| Link to monitoring thresholds | ? |
| Step-up and step-down language | ? |
VAL sources and links
The images below are static examples of VAL information pages and DO NOT represent current alert levels. While we strive to maintain the links below, they may not always work. For the current alert level, please consult the proper institutional authorities.
Social Media Reports
