Revista Scientific American Noviembre 2017. Inglés

Revista Scientific American Noviembre 2017. Inglés

ISSN: 0036-8733

Descripción

How to Make a Consciousness Meter
Zapping the brain with magnetic pulses while measuring its electrical activity is proving to be a reliable way to detect consciousness

I have died many times over. Every night when I lay down my weary self to rest, my consciousness is extinguished. I experience nothing until I wake up inside my sleeping body
in a dream disconnected from the external world. Or later consciousness resurfaces in the morning on my return to the wakening world.

A chain of volcanoes running up America’s West Coast imperils millions of people. Mount St. Helens is the most infamous and deadly.

New methods of probing inside the mountain show surprising ways that molten rock moves from the deep earth through intricate networks of conduits.

Signals of these movements and of chemical changes in magmas may help forecast the timing and danger of coming eruptions here and at similar volcanoes.

Early on the morning of May 18, 1980, Arlene Edwards, a freelance photographer from Portland, Ore., and her 19-year-old daughter, Jolene, drove across the Columbia River to a high outcropping of rock in southwestern Washington State. There they set up Arlene’s camera and began to watch the Mount St. Helens volcano 10 miles to their southeast. For the previous two months the volcano had been spitting out ash and steam, and the Edwardses were among dozens of observers on surrounding ridges who thought they were a safe distance away. It was a gorgeous Sunday morning, the air warm and still beneath a cloudless sky, the volcano grand and terrible under its ash-streaked glaciers.

Suddenly, the entire north side of Mount St. Helens began to slide into the adjacent valley. An angry, gray cloud of pulverized rock and hot gas leaped from the void that had been a mountainside seconds before. The cloud grew explosively, filling the eastern sky and rushing toward Arlene and her daughter. When the cloud hit the viewpoint on which they stood, it blew Arlene 1,000 feet away; her body was later found tangled in the branches of a hemlock tree below the ridge. Jolene, dead of ash asphyxiation, was found near her mother’s pickup. Around the mountain, 55 other people lay dead or mortally wounded, victims of an eruption much larger than geologists anticipated.