Volcano alert levels: rankings and impacts
The United States Volcano Alert-Notification system analyzes ground-based impacts and aviation hazards.
With the recent eruption of New Zealand’s White Island volcano, many questions have come up as to why it wasn’t flagged for possible eruption?
White Island was in fact termed an ‘Alert Level 2’ volcano with ‘moderate to heightened volcanic unrest’. But volcanologists stress that an eruption may occur at any alert level, and levels may not move in sequence as activity can change rapidly.
New Zealand’s Volcanic Alert System
New Zealand’s ‘Volcanic Alert Levels’ range 0 to 5 and are based on volcanic activity. Each volcano in the country is given a level based on it’s activity and is monitored for changes.
United States Volcanic Alert System
The United States uses different criteria when ranking volcanoes.
The United States Geological Survey (USGS) recently standardized their nationwide alert-notification system for volcanoes. The alerts are issued by five regional volcano observatories – most located along the coast of the Pacific Northwest and Hawaii. The group monitors and analyzes ~170 active volcanoes located in Alaska, Arizona, California, Colorado, Hawaii, Idaho, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming, American Samoa and the Commonwealth of the Northern Mariana Islands.
The alerts are two fold — one part for ground-based impacts, the other for aviation hazards.
The ground-based Alert Levels are termed like weather alerts… with ‘normal’ meaning typical conditions… increasing in intensity to ‘advisory’, ‘watch’ and finally ‘warning’, meaning eruption is imminent or suspected.
The Aviation Color Code uses a ranking system comprised of four colors to express a volcano’s impact on the aviation sector. The color code puts emphasis on volcanic ash distributed into the atmosphere as this can be extremely detrimental to jets, causing loss of power or engine failure.
Volcano alert terms and color codes can change with time which is why their observed, analyzed and researched for re-evaluation often.
Fore more information on the USGS Alert-Notification System, click here.