Note: This VAL system was in use from 1997–1998. The current VAL system can be found here.
Agency: United States Geological Survey (USGS)
Name: Level of Concern Color Code
Elements of VAL system
| Domain | Terrestrial and Aviation |
| Volcano | Alaska |
| Scheme range | 4-level scale |
| Lowest level | 1 |
| Highest level | 4 |
| Level name type | Color |
| Level for lack/loss of monitoring | No |
| Volcanic activity | Yes |
| Hazards possible | Yes |
| Locations affected | Yes |
| Potential impacts | No |
| Forecast language | Yes |
| Timing language | Yes |
| Actions to take | No |
| Agency actions | No |
| Link to evacuations | No |
| Reporting frequency per level | No |
| Link to monitoring thresholds | No |
| Step-up and step-down language | No |
Related References
Fearnley, C. J., McGuire, W. J., Davies, G., & Twigg, J. (2012). Standardisation of the USGS Volcano Alert Level System (VALS): analysis and ramifications. Bulletin of Volcanology, 74(9), 2023-2036. https://doi.org/10.1007/s00445-012-0645-6
Guffanti, M., & Miller, T. P. (2013). A volcanic activity alert-level system for aviation: review of its development and application in Alaska. Natural hazards, 69(3), 1519-1533. https://doi.org/10.1007/s11069-013-0761-4
Neal, C. A., Casadevall, T. J., Miller, T. P., Hendley II, J. W., & Stauffer, P. H. (1997). Volcanic Ash-danger to aircraft in the North Pacific (No. 030-97). US Geological Survey. https://doi.org/10.3133/fs03097
Waythomas, C. F., Power, J. A., Richter, D. H., & McGimsey, R. G. (1998). Preliminary volcano-hazard assessment for Akutan Volcano, east-central Aleutian Islands, Alaska (No. 98-360). pg. 33 US Geological Survey. https://doi.org/10.3133/ofr98360