The Ten Most Hazardous US Volcanoes


Update, October 29, 2018: The Yellowstone Observatory posted more information on Yellowstone Caldera’s ranking and on the threat assessment process today.


Original post:
It’s a little early to be making top-ten lists for 2018, but the USGS just released their 2018 update to the National Volcanic Threat Assessment:


https://platform.twitter.com/widgets.js

The link takes you to an abstract of the report and a free PDF download.

Note that threat level doesn’t mean that the volcano is about to erupt. They looked at the bigger picture, placing volcanoes according to how they scored on a list of potential hazards.

If we had assessed only the hazards aspects of U.S. volcanoes, then the generally more explosive volcanoes in Alaska and CNMI [the Marianas**] would be more strongly represented in the higher (more hazardous) ranks. Because we include exposure factors in the assessment, volcanoes in CONUS are more strongly represented in the highest threat category owing to the greater nearby ground-based and airborne population, and more critical infrastructure exposed to volcano hazards . . .Eleven of the 18 [very high threat] volcanoes are in Washington, Oregon, and California, where explosive and often snow- and ice-covered edifices can project flowage hazards long distances to reach densely populated and highly developed areas. Five of the 18 volcanoes are in Alaska, near important population centers, economic infrastructure, or below busy air traffic corridors. The remaining two very high threat volcanoes are on the Island of Hawai╩╗i, where densely populated and highly developed areas now exist on the flanks of highly active volcanoes. Large eruptions from any of these very high threat volcanoes could cause regional- or national-scale disasters.

**: In its October 26th weekly update, the USGS says that Supertyphoon Yutu has destroyed ground-based monitoring equipment on Saipan, affecting all CNMI volcanoes, including Farallon de Pajaros, Supply Reef, Maug, Asuncion, Agrigan, Sarigan, Pagan, Almagan and Guguan. Only satellite monitoring is possible now.

Ten Most Hazardous Volcanoes

The ten highest-threat volcanoes on the list are:

1. Kilauea, in Hawaii. We know. We know.

2. Mount St. Helens, in Washington. Global Volcanism page (GVP). Local volcano observatory (VO) page. Wikipedia page.

3. Mount Rainier, in Washington. GVP. CVO. Wikipedia. Continue reading

Advertisements

Guest Video: The Salton Sea


A study at the end of June made headlines about earthquake hazard on the San Andreas Fault. The research looked at the area covered by the Salton Sea:



According to news reports, geologists found:

. . . a nearly 15.5-mile-long, sheared zone with two, nearly parallel master faults and hundreds of smaller, rung-like cross faults. . . The discovery . . . reveals the southern tip of the San Andreas Fault changes fairly gradually into the ladder-like Brawley Seismic zone. The structure trends northwest, extending from the well-known main trace of the San Andreas Fault along the Salton Sea’s northeastern shore, to the newly identified East Shoreline Fault Zone on the San Andreas’ opposite edge.

. . .

Future earthquakes in that zone or near the San Andreas Fault could potentially trigger a cascade of earthquakes leading to the overdue major quake scientists expect along the southern San Andreas fault zone . . .

So, perhaps it’s good that the “Riviera” scheme never worked out.

While seismologists scramble over the area to learn more about earthquake hazards, the USGS is monitoring the local volcano situation–which includes five vents discovered in 2013–through the California Volcano Observatory.

Again, not a good place for a resort!


Featured image: 12019, at Pixabay. Public domain.