The Earth Needs to Blow off Some Steam ; Volcanoes Aren't Just for Show - It Turns out We Need Them

Article excerpt

If you don't like active volcanoes, go to Mars. But be prepared to become your own life support system.

As the authors of this interesting little book put it: "Volcanism is the surface manifestation of a living Earth." Volcanoes are relief valves for the high-pressure system that recycles large chunks of the outer crust through the planet's molten interior and returns life-sustaining materials to the surface.

Volcanoes have supplied much of our water. Their ash falls have enriched soils. Their gases have helped form our atmosphere. If Mars' recycling system hadn't shut down eons ago, life might thrive there today.

Humans have a precarious cost-benefit relationship with this essential phenomenon. We can catch a lot of grief when volcanoes explode or ooze all-consuming lavas.

Geoscience now mediates that relationship as our growing understanding of volcanic mechanisms helps us better manage the risks. This makes volcano science a humanistic enterprise.

That's the authors' main point in "Volcanoes in Human History." They could have made it with more verve and poetry, but their somewhat stodgy style serves their intent not to focus merely on dramatic accounts of volcanic carnage.

The authors - Jelle de Boer, a volcanologist, and Donald Sanders, a geologically informed science writer - have a larger perspective. They show how political, economic, and environmental consequences of that carnage can reverberate for centuries.

For instance, there's well established, although not definitive, evidence that a major Bronze Age eruption changed the course of Mediterranean history over 3,500 years ago. It happened at Thera, one of the Santorini Islands some 70 miles north of Crete.

Immediate environmental effects - tsunamis, ash falls, and possibly atmospheric shock waves - devastated Crete's powerful Minoan civilization. Mycenaean Greeks took over and extended their influence throughout the eastern Mediterranean.

The authors have little to add to this well known tale. But their insight lies in connecting the volcanic system responsible for the event to the on-going history of that region. …