Special Report

50 Most Dangerous Volcanoes in America

The ongoing eruption of the Kilauea Volcano in Hawaii has devastated a large portion of the Big Island — the most southern island of the archipelago. Rivers of lava have inundated and permanently destroyed farmlands, roads, and other infrastructure. Toxic gases from the eruption have also endangered the health of area residents.

Charlie Mandeville, volcanologist and director of the U.S. Geological Survey volcano hazards program discussed some of the recent developments and dangers.

“[In 48 hours], we’ve seen a threefold increase in the SO2 concentrations,” Mandeville told 24/7 Wall St. SO2, or sulfur dioxide, combines with moisture in the atmosphere to form fog or vog — “sulfuric acid aerosol particles that are sub micron in size.” Because these particles are so easily breathed in, “even healthy people in proximity of such areas are facing health problems potentially if they’re exposed for long periods of time.”

Advancements in gas emission sensors, seismometers, aerial GPS, radar systems and other monitoring instruments have revolutionized the science of predicting volcanic eruptions. With such tools deployed on Kilauea, Mandeville explained, ground swells were detected before the most recent explosion, giving emergency responders several days of warning. It is possible to predict major eruptions weeks or months ahead of time, he added.

Still, predicting volcanic eruptions is generally very difficult. Based on what is known from geological research, Kilauea is just one of a great many active volcanoes with high threat potential.

Approximately 800 million people live within 60 miles of an active volcano in over 80 countries around the world. There are 169 active volcanoes in the United States. Based on the latest USGS estimations of volcanic threat level, 24/7 Wall St. ranked these volcanoes from lowest to greatest level of potential threat.

Threat scores of 123-324 are considered very high; scores of 64-113 are considered high; and scores of 30-63 are called moderate. Threat levels take into account both the estimated likelihood of eruption based on eruption history and geological studies as well as possible damages based on population density and surrounding infrastructure.  The threat levels of the 50 most dangerous volcanoes are high or very high.

Click here to see the 50 most dangerous volcanoes in America.
Click here to see our detailed findings and methodology.