National Geographic: Forces of Nature

Planet Earth four-and-a-half billion years ago a blazing sphere formed by colliding cosmic matter a violent world covered by a sea of molten lava, over time the surface cooled into a rocky crust. Great clouds of water vapor rose then rained down, forming a vast ocean the crust fractured into huge moving plate that shifted the emerging continents producing the face of the planet we know. But the forces that created Earth still rule it.

Around the globe sweeps a volatile atmosphere and within a fiery world still burns, floating on this semi-molten interior the plates of the crust are forever in motion. Only in a thin layer between the inner heat and the atmosphere could life arise and thrive yet always at the mercy of these colossal forces, erupting from the depths, shaking the solid ground, descending from the sky. We cannot control such power.

But we can use our human powers of invention and discovery to learn to understand, and to survive there are places where primal forces are still on display. Where lava streams freely from the earth’s interior yet these same forces can also erupt suddenly, unpredictable, with terrible consequences.

For hundreds of years, a volcano called Soufriere Hills on the Caribbean island of Montserrat was dormant, but in 1995, some twelve-thousand islanders discovered they were living on a time bomb. Deadly cascades of ash, gas, and lava rocks called “pyroclastic flows” raced down the mountain at temperatures as hot as a thousand degrees.

The eruptions continued burying the capital of Plymouth under ash, but there was time to evacuate the population of about four thousand and no lives were lost here. Yet outside the city, pyroclastic flows killed nineteen people who had ignored the warnings.