Part 2: Extinction-level supervolcano growing in the Pacific

February 12, 2013 – RING OF FIRE – Bad news, everyone – you have another near-certain world-ending catastrophe to look forward to. Scientists have confirmed that two continent-sized chemical blobs of partially melted rock are converging in the Pacific, and look set to create a massive new volcano, which could prove cataclysmic to life on Earth. Geologist Michael Thorne at the University of Utah reports in Earth and Planetary Science that the collision is slowly happening 1,800 miles beneath the ocean. He says that the collision could lead in two possible directions – both of which are bad, and would wipe out millions of species. One is just a massive single eruption, which would kill us all, the other is a thousand-year flood basalt eruption, which would also kill us. The problem is that two enormous “thermochemical piles” of molten rock about 3,000 miles across are moving towards each other at the bottom of the Earth’s mantle. The piles have been known about for decades, but it was originally thought they were static. But after extensive study with seismic waves, Thorne is convinced they’re in fact moving together. The result is a massive, molten blob that will one day be created beneath the ocean, creating a huge amount of pressure that will eventually blow up in our face. “What we may be detecting is the start of one of these large eruptive events that – if it ever happens – could cause very massive destruction on Earth,” said Thorne. Luckily the process is slow – it shouldn’t happen for another 100 million years or so. –Huffington UK

Trouble in the Pacific: But in the 1990s, geophysicists found evidence for the continent-size thermochemical piles beneath Africa and the Pacific. These are known technically as LLSVPs, or “large low shear velocity provinces,” because seismic shear waves passing through them move 5 percent slower that through surrounding mantle rock. That suggests they have a different composition and-or temperature than the surrounding mantle. Previous studies also have observed smaller blobs of rock, measuring perhaps 60-by-60 miles on the edges of the continent-sized masses. Seismic shear waves move as much as 45 percent slower through these blobs – known technically as ULVZs or “ultra low velocity zones” – indicating they may be spongy and partly molten. Thorne says his analysis of seismic waves passing through the core-mantle boundary reveals the Pacific pile really represents two or more continent-sized piles slowly sliding atop the core and colliding so that partly molten blobs on their edges are merging into the largest such blob or ULVZ ever observed – roughly the size of Florida. “My study might be the first to show actual seismic evidence that the piles are moving,” he says. “People who have done previous simulations have suggested this. They are sitting atop the core and getting pushed around by overlying mantle forces like subduction. They move around on the core somewhat like continental plates drift at Earth’s surface.” -UU