PHOTO: Glenn Zorpette

LOFTY GOALS: Anténor-Habazac on La Soufrière.

On top of La Soufrière, an active volcano in Guadeloupe, Christian François Anténor-Habazac is a happy man. At 1467 meters above sea level, he is as high as you can get in all the Lesser Antilles. The stunning view, intermittently unveiled by the swirling fog, is of jagged green peaks and, beyond them, the red roofs of the capital town of Basse-Terre on the edge of the calm blue Caribbean Sea.

Anténor-Habazac is standing next to a crater that’s roaring like a jumbo jet and shooting out steam and poisonous hydrogen chloride. The wafting gas stings the eyes and lungs of a first-time visitor who is trying to take Anténor-Habazac’s picture, but it can’t wipe the smile off the engineer’s face. “Don’t let your camera get too close” to the gas, he helpfully advises. “It will wreck it.”

Anténor-Habazac is technical manager of the Observatoire Volcanologique et Sismologique de Guadeloupe, a unit of the Institut de Physique du Globe de Paris, the renowned French geophysical agency. It is his responsibility to design, install, and maintain the radio-based sensor networks that monitor the region’s seismicity and that would give officials warning of any impending eruption.

It’s an important responsibility in this lush cluster of islands, which, as an overseas ­département, are as much a part of France as the left bank of the Seine. La Soufrière last erupted for eight months starting in July 1976, sporadically spewing ash and rock. The falling debris didn’t kill anyone, but elsewhere in the eastern Caribbean, volcanoes have claimed tens of thousands of lives in the past few centuries. In 1902, for example, an eruption in Martinique killed 29 000 people in 2 minutes; it is often cited as the Western Hemisphere’s single deadliest event in the 20th century.

Nevertheless, the young Anténor-Habazac, growing up in Guadeloupe’s commercial center, Point-à-Pitre, was captivated not by volcanoes but by radios. When he was 9 years old, he built a crystal set with a coil made from copper wire wrapped around a toilet-paper tube. He literally jumped for joy when it worked, and it was the first of many radios and antennas to come, most built with scrounged or salvaged parts. At age 19, he went off to Paris, where he earned an associate’s degree in 1972 from the École Centrale d’Électronique and a master’s in 1976 from the École Français d’Électronique et d’Informatique. He had just started working on an antenna and other systems for the Mirage 2000 fighter jet when, back home, Soufrière exploded.

The French government decided it was time to significantly expand the sleepy little monitoring station it had set up near the volcano. Among the positions the government was looking to fill was one for an EE. For Anténor‑Habazac, the job would accomplish two things: get him back to Guadeloupe, where most of his friends and family were, and fulfill his French government-service obligation. He was hired in November 1976 and returned to Guadeloupe a month later.

Nowadays he presides over a network of 250 monitoring stations and five radio-repeater installations that keep tabs on the volcano and its environs. Virtually all the stations are solar powered, and about a third of them are fully automated, transmitting their data by VHF or UHF radio. At the observatory, data are gathered, processed, and put online by software written by Anténor-Habazac and two colleagues. Any of the scientists who work at the observatory or at its parent agency in Paris can go to a Web page to see, in near–real time, seismic and other data gathered in Guadeloupe.

The observatory’s sun-filled main building sits on the peak of an extinct volcano. It’s an architectural gem, a four-story tower built in 1993, with a central stairway spiraling to a perch from which sprout a score of antennas that pull in signals from the sensor stations. The panorama is breathtaking: to the north, 8.5 ­kilometers away, is fog-shrouded La Soufrière; to the east lies Monts Caraïbes, an extinct volcano complex; to the south and west, the blue Caribbean and scattered rain forest.

In the tower, Anténor-Habazac has a tidy office, a computer room for the 20 or so PCs that process and store sensor data, and an electronics lab where he designs, builds, tests, and fixes boards and other systems for the sensor stations. But on any given day he’s as likely to be out in the field—installing equipment on the volcano, servicing a station, or giving a talk on the volcano to a school, community, or business group; a few days ago, he was on the resort island of St. Barthélemy giving a lecture to utility executives. Every now and then, he’s in Paris, sharing his expertise at the observatory’s parent institute.

A sunny morning in early October finds him headed for the summit of Soufrière and a rendezvous with Dominique Gibert, a professor of geophysics at the University of Rennes, in northwestern France. On the way up, Anténor-Habazac climbs steadily, fortifying himself with sweet, gooey, dried bananas that he takes from a package in his green climbing suit.

Anténor-Habazac and Gibert have been studying a mysterious water-filled crater, named Tarissan, up on the summit. The water’s surface is 110 meters down from the rim of the crater, and the crater’s depth is several tens of meters. It’s hard to measure more precisely because the water is boiling and is so acidic that its fluctuating pH is usually negative.

The two men believe Tarissan is the crux to understanding how heat and water propagate through the volcano and, therefore, how the volcano might behave in the future. Soufrière is a subduction volcano—which means that its fire and fury come from a region deep below the volcano where two ­tectonic plates are colliding and sliding, one over the other. Anténor-Habazac has been trying to design some casings to protect temperature sensors, hydrophones, and other electronics from the boiling acid, but so far he’s had little success. Some heavy-gauge stainless steel and aluminum fixtures he tried recently were eaten away within two months.

Today, the investigators want to collect samples of the seething liquid. But after they stretch some guide ropes across the rim, the clouds open up. Forty minutes later, with the rain still coming down hard, Anténor-Habazac slings his pack over his shoulders and heads down the volcano.

A couple of hours later, he is sitting outdoors at a charming restaurant in St. Claude, relishing his first real meal of the day. He starts with a petit punch—clear, bracing Guadeloupean rum mixed with a bit of raw cane sugar and fresh lime juice. It blasts away the lingering chill from the soggy trek. Then there’s pea soup and a wonderfully satisfying goat curry—“the only true curry,” Anténor-Habazac insists, as he minces an orange habanero chili to put on top of it.

Nearby, the street teems with children playing and adults strolling to markets and offices. The life and bustle remind Anténor-Habazac why his monitoring networks matter: St. Claude will almost certainly be the first town pulverized the next time Soufrière blows its top.

But for now, as the sun sinks behind nearby palm trees, the engineer is in a mood to reflect on his life and career. “I like radio technology,” he says. “I just always want to connect something to something else.”