There are about 169 volcanoes in the United States that scientists consider active (source). Most of these are located in Alaska, where eruptions occur virtually every year. Others are located throughout the West and in Hawaii (Ring of Fire anyone?).
There are several ways we minimize the danger of volcanic activity (apart from the obvious of ‘getting out of the way’…(:
· Forecasting (earthquakes as early warnings -although a Japanese volcano erupted without any previous seismicity (livescience article), land swelling before eruption, gas emissions, etc.)
· Volcanic Alert Codes (USGS): the levels of alert and the aviation code levels commonly change at the same time (chart on right). A non-erupting volcano will have a green icon, and a red one indicates an imminent eruption (see USGS Alert Codes).
Today the US hazards map (below) shows 5 volcanoes as to be above normal background (elevated unrest); map below:
Kilauea and Great Sitkin, Alert Level= WATCH. Aviation Color Code = Orange.
Spurr, Atka, Ahyi Seamount, Alert Level= ADVISORY. Aviation Color Code = Yellow
If you want to know more about volcanoes and how we monitor them, there is a MOOC from the University of Iceland you might want to enroll into. A short video explanation here.
ReplyDeleteHello Professor Garcia,
I never realized the U.S. had so many active volcanoes! It is crazy how Alaska experiences eruptions almost every year. The alert system is a smart way to keep people informed. Can you imagine living near one of these and constantly checking if it is green or red! In Brazil, they do not have any active volcanoes, but the landscape still tells stories of ancient eruptions. It is great to learn how different regions deal with volcanic hazards, while the U.S. prepares for eruptions, Brazil just gets to study the remnants of their volcanic past! Great Information!