Drilling To The Core

In Jules Verne's classic 19th-century novel "Journey to the Center of the Earth," Professor Lidenbrock travels to a mysterious subterranean world. Now a Japanese ship is aiming to replicate his adventure, striking out on its own quest to explore the earth's depths. In August, the massive 57,000-metric-ton Chikyu ("Earth"), a cutting-edge deep-sea drilling vessel, left Nagasaki on a test run. Though the Japanese venture may not reveal the prehistoric monsters or hidden oceans that Lidenbrock's journey did, it is hoping to reach unprecedented depths.

The ship faces a daunting task. Over the past few decades, scientists have managed to dig only 2,111 meters into the earth from the ocean floor--a mere scratch, given that the distance to the earth's core is about 6,400 kilometers. But the Chikyu is far better equipped than its forerunners. Operated by Japan's Center for Deep Earth Exploration (CDEX), the vessel measures 210 meters long and is capable of drilling 4,000 meters underwater and an additional 7,000 meters from the ocean bed to the mantle--which no one has ever reached--more than tripling the previous record depth.

The boat uses technology adapted from the oil industry, including large-diameter riser pipes that connect the vessel to the head of the well on the ocean floor and guide the drill. A 380-metric-ton "blowout preventer" acts as a vital shield, protecting the vessel from unexpected eruptions of gas, oil and other fluids. With a price tag of $582 million, the Chikyu can accommodate 150 people, who can fly on and off the ship by means of a large helicopter pad. It also features a highly sophisticated four-story laboratory, where scientists can study sediment samples brought almost intact from the core. "It's amazing how little we know about our own earth," says Shinichi Kuramoto, who leads scientific operations at the CDEX. "It's time we look at where we stand--instead of looking up--and study what's underneath."

The Chikyu has plenty of international cooperation, from the United States as well as other countries. But its mission is especially near and dear to Japan, an archipelago that is frequently hit by earthquakes. Scientists hope to improve their prediction capabilities by drilling directly into the spot where the tectonic plates meet and installing monitoring devices. The Chikyu may also shed light on events like the devastating tsunami that struck off the coast of Sumatra in December 2004.

It may take a while, though. Full-scale drilling is not scheduled to begin until the fall of 2007. If the operation to drill into the mantle--which accounts for more than 80 percent of the earth's mass--is successful, "it will be the first time we will ever see the rocks at that depth," says Hidenori Kumagai, a geochemist at the Japan Agency for Marine-Earth Science and Technology (JAMSTEC). "We might find clues to the earth's evolution." Nanako Ogawa, a paleoenvironmental scientist, calls the drilled core samples "tape recorders" that reveal how the earth's environment has changed over the last 4.6 billion years. "The present environment we see now has a short history, compared with the history of the earth," says Ogawa. "Studying the earth's past will help us forecast the future."

Some scientists hope the mission will reveal more about how biological life developed on earth. The environment at 7,000 meters is estimated to have a temperature of 300 degrees Celsius, with low water content, low oxygen and poor nutrient conditions. But they believe there may be bacteria at that depth. "I want to know more about the relationship between the environmental conditions and the microbes as we go deeper," says microbiologist Hiroyuki Yamamoto. "The drilling will tell us about the ecosystem and if there are any creatures that can live in such an extreme environment." In a CDEX newsletter, director-general Asahiko Taira recently bolstered their hopes: "We believe there has to be life there. It's the same mission as searching for life on Mars." Except these Japanese scientists are more likely to find prehistoric fossils than aliens.

Drilling To The Core | News