When Earth Attacks

Tsunamis, volcanoes, hurricanes, landslides--The single certain thing about nature´s killers is that they will strike again, and again. Our only defense: ever better prediction and protection

| Published Apr 15, 2005 1:00 AM

Environment

Humans are fleeting visitors on this roiling rock in the universe. On December 26, 2004, at 58 minutes and 49 seconds past midnight GMT, Mother Earth reacquainted us with this immutable fact. For millions of years, a creeping slab of Earth´s crust–the India Plate–had been grinding headlong into a similarly stubborn chunk of rock called the Burma Plate. Like a clash of Brobdingnagian armies, millennia of pent-up kinetic energy suddenly exploded from the seabed, a scant 100 miles from Sumatra, Indonesia. The ensuing force–equal to 25,000 Nagasaki-size atomic bombs detonated in tandem– jolted the Earth from its axis, permanently shortened the length of the day, and hurled walls of seawater onto thousands of miles of coastline–from the Andaman to the Arabian–sweeping away at least 200,000 lives in an instant. What´s most terrifying about the recent tsunami is that a repeat performance is virtually guaranteed. Earth, by its very nature, is a prolific architect of mayhem and purveyor of calamity. The only thing we can do to protect ourselves is strive to learn where and when such massive natural disasters will happen–because rest assured, they will happen.

Fortunately, advances in remote-sensing satellites, computer-modeling simulations, radar, seismic monitors and weather forecasting are giving scientists an edge, in many cases enabling them to warn us when it´s time to skedaddle. Researchers use imaging satellites, for example, to track minute changes in land deformation–an otherwise undetectable pimple might mean that a fault is about to snap or a volcano about to blow.

Not that this high-tech ingenuity is necessarily making the world a safer place. The problem, experts say, is that humans are doggedly encroaching on Mother Earth´s most temperamental turf, increasingly building and living in potentially catastrophic hot zones. And more is at issue than
just our propensity to boldly skirt the â€urban interface,â€ as scientists describe the boundary between a safely inhabitable region and an area known to be vulnerable to nature´s wrath. Humans are also relentlessly altering or destroying the planet´s natural protection mechanisms. “If you remove angroves, damage coral reefs, and take away wetlands,” argues Ellen Prager, a marine geologist and author of Furious Earth: The Science and Nature of Earthquakes, Volcanoes, and Tsunamis, “you are much more exposed to storm impact or tsunami damage.”

The bad news is that the danger is only growing, because wherever population densities soar, the landscape must be transformed to sustain more and more people. The good news: Digital-imaging and mapping tools and ever more savvy computer models are improving scientists´ ability to calculate where the most deadly disasters might strike next.

MT. ST. HELENS

The eruption melted the mountain´s snowcap; when this meltwater mixed with ash and dirt, it formed destructively voluminous mudflows. One such â€laharâ€ reached the Columbia River, 70 miles away, and blocked its shipping channel with millions of cubic yards of sediment.

KILAUEA

Lava breaks through the cooling crust to continue the formation of a new tributary. Most shield volcanoes, including Kilauea, erupt low-silicon basalt, which results in a more fluid lava.

MT. ST. HELENS

After

KILAUEA

Lava tubes, created by recurring 10 -to 100-yard lava flows that build up walls and eventually form a roof over the flow, act much like a river delta, allowing the molten rock to quickly reach the ocean.

MT. ST. HELENS

Before Fir and mountain hemlock trees covered the base of the volcano. The blast flattened 230 square miles of forest. Shown here, before and after images seen from Johnston Ridge.

MT. ST. HELENS

MT. ST. HELENS

The ash from the May 18, 1980, eruption of Mount St. Helens traveled at least 12 miles high and eventually moved eastward at 60 mph, layering eastern Washington and Idaho.

KILAUEA

Lava plunging into the Pacific at dusk.

MT. ST. HELENS

KILAUEA

Lava enters the ocean surface in a whirl of steam from evaporating water. Only cooled lava crust remains behind on the ridge to support later eruptions.

MT. ST. HELENS

On March 8 of this year, a small explosion rocked Mount St. Helens. Airplane pilots verified that the resultant smoke and ash reached an altitude of 36,000 feet.