Volcanoes

The odds that this particular volcanic eruption will cause a mega-tsunami are less than one in a hundred, maybe one in a thousand. Even if a tsunami from La Palma did reach the Americas, the wave height might be less than one metre. But the risk of unpredictable, life-altering events is real.

We can do nothing about flank collapses on volcanic islands except have a good early warning system, but they are only common in the Hawaiian Islands, the Canary Islands and the Indonesian archipelago. Then there’s asteroid strikes, global plagues and nuclear winters, of course, but let’s stick with volcanoes.

Just east of the Rocky Mountains in the west-central United States, Yellowstone Park has staged three long-lasting super-eruptions at 2.1 million, 1.3 million and 631,000 years ago.

Each time it covered the surrounding states with volcanic ash a metre thick, coated the entire continent with enough ash to kill most green plants and boosted over 1,000 cubic kilometres of pulverized rock and gas into the atmosphere.

That blocked much of the incoming sunlight for the next six to 10 years and caused a volcanic winter, with 3 or 4 C lower average global temperature. If that happened today, it would cause global crop failures and mass starvation.

There have been at least 47 such super-eruptions in the world’s history.

https://www.kamloopsthisweek.com/opinion/dyer-volcanoes-tsunamis-and-ris...

Tue, 2021-10-12 21:44

#11

NorthReport

A Huge Subterranean ‘Tree’ Is Moving Magma to Earth’s Surface

Deep in the mantle, a branching plume of intensely hot material appears to be the engine powering vast volcanic activity.

RÉUNION, A FRENCH island in the western Indian Ocean, is like a marshmallow hovering above the business end of a blowtorch. It sits above one of Earth’s mantle plumes—a tower of superheated rock that ascends from the deep mantle and flambées the bases of tectonic plates, the jigsaw pieces that make up the ever-changing face of the world. The plume’s effects are hard to miss: One of the island’s two massive volcanoes, the aptly named Piton de la Fournaise, or “Peak of the Furnace,” is one of the most hyperactive volcanoes on the planet.

But the plume’s modern-day punch is nothing compared to its past.

https://www.wired.com/story/a-huge-subterranean-tree-is-moving-magma-to-...