Why doesn't GVP post alert levels?
The assignment of official hazard status designations, often call volcanic alert levels, is the responsibility of national or regional volcano observatories, civil defense agencies, or other designated government officials. Each country creates their own protocols for inter-agency responsibilities, communication, and collaboration. The following discussion is adapted from content provided by the World Organization of Volcano Observatories (WOVO), with permission.
In a volcanic crisis, there is often worldwide interest in the volcano's hazard alert levels. With the exception of color codes for aviation (see below), though, there is no standardized international volcano alert levels system. This is due to: (a) wide variation in the behavior of individual volcanoes and in monitoring capabilities, and (b) the different needs of populations, including different languages and symbolism of colors used. National volcano observatories have developed hazard status protocols that are regionally variable and differ significantly in detail. The WOVO site contains links to the regional volcano observatories and the alert systems they utilize.
Organizations with an interest in natural hazards are strongly cautioned against posting global volcano hazard alerts or eruption "forecasts" that do not originate from official agencies with both responsibility for, and familiarity with, those volcanoes. Posting of alert levels can have major public safety and economic implications, and should be done with care. The data needed to provide alert levels come from onsite and remote monitoring instrumentation and are best evaluated by staff of regional volcano observatories who are the most familiar with activity at their volcanoes. Any re-posting or publication of an official hazard status or alert level should include the date (and time if available) that the status became effective, the broad parameters of the system being used, the issuing agency, and a link (if appropriate) so that users can easily find the most current information. The responsible observatories and organizations are listed on the WOVO website, and readers are directed to these organizations for information on current volcano alert levels.
There is no WOVO-endorsed source of worldwide volcanic alert levels, with the exception of aviation color codes. For those seeking a near real-time overview of current reported activity that incorporates direct observatory sources WOVO recommends the Weekly Volcanic Activity Report compiled by the Smithsonian Institution's Global Volcanism Program and the U.S. Geological Survey's Volcanic Hazards Program.
Many instances of aircraft flying into volcanic ash clouds have demonstrated the life-threatening and costly damages that can be sustained. Consequently, a global volcanic alert level system for aviation has been developed (as part of the International Airways Volcano Watch, a universal warning system coordinated by the International Civil Aviation Organization, a UN specialist agency). This system uses four color codes, designed to help pilots, dispatchers, and air-traffic controllers quickly find the status of numerous volcanoes that might endanger aircraft.
The color codes reflect conditions at or near a volcano and are not intended to indicate hazards posed downwind by drifting ash - all discernible ash clouds are assumed to be highly hazardous and to be avoided. The aviation color code should not be extrapolated to represent hazards posed on the ground, which might be quite different. Local observatories may have a completely different system to describe ground hazards independent of the ACC. The color codes are defined as below.
|Aviation Color Code||Definition|
|GREEN||Volcano is in normal, non-eruptive state. Or, after a change from a higher level: Volcanic activity considered to have ceased, and volcano reverted to its normal, non-eruptive state.|
|YELLOW||Volcano is experiencing signs of elevated unrest above known background levels. Or, after a change from higher level: Volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase.|
|ORANGE||Volcano is exhibiting heightened unrest with increased likelihood of eruption. Or, volcanic eruption is underway with no or minor ash emission. [specify ash-plume height if possible]|
|RED||Eruption is forecast to be imminent with significant emission of ash into the atmosphere likely. Or, eruption is underway with significant emission of ash into the atmosphere. [specify ash-plume height if possible]|
Global Volcanism Program, 2013. Volcanoes of the World, v. 4.8.1. Venzke, E (ed.). Smithsonian Institution. Downloaded 17 Jul 2019. https://doi.org/10.5479/si.GVP.VOTW4-2013