The Last Volcano Read online

  All of his American colleagues had departed Martinique when Jaggar returned on June 24. Two weeks later, on July 9, he was in Fort-de-France and, as he would recall, “I had the good fortune to see an eruption of the first magnitude on Mount Pelee.”

  It was 8:20 in the evening and the sky was darkened by twilight. He was inside a local library when someone entered and, recognizing him, told Jaggar that something extraordinary was happening on the volcano. He rushed to look.

  People were already in a panic on the street. Looking in the direction of Mount Pelée, Jaggar could see a column of black clouds billowing up to a great height. Within minutes, the top of the column had spread out and covered most of the sky.

  Jaggar hurried to a nearby hotel and climbed to the roof to get a better look. The night air was still. He heard only the hum of tree frogs and crickets and a faint low roar coming from the volcano. He stood and waited. Soon a fantastic light show—one that he would later say he had never thought was possible—began.

  On the edge of the eruptive cloud were shimmering points of white lights. As time progressed, these points grew into bolts of lightning that passed into and out of the cloud, the flashes becoming more frequent and grander as the eruption progressed. At one point, about an hour after the display had begun, the whole cloud was filled with dancing lights. And then there was the thunder.

  At first, the rumbling overhead could barely be heard. But that soon evolved into sequences of thunder rolling across the sky. A sequence began as a bubbling growl that grew into a crescendo. The pattern of lightning also changed. At the height of the display, lighting shot out of the eruptive cloud as long serpents, then as sheets, illuminating the entire sky. One remarkable flash made a complete loop, arching out and down from high on the cloud, touching the top of the volcano, then curling back up again.

  The display of lightning and thunder lasted two hours. At daybreak, anxious to see what had happened nearer the volcano, Jaggar hired a small boat to take him to St. Pierre.

  When he arrived, he discovered that the explosive eruption of the previous night had covered the ruined city with yet another blanket of volcanic ash. And there was something else that he encountered that day at St. Pierre. He met two other scientists who were also inspecting the ruins. They had recently arrived and had seen the previous night’s eruption at extremely close range.

  Responding to the May 7 eruption of Soufrière on St. Vincent—the island was then a British colony—the Royal Society of London had sent two scientists to investigate. One was a noted professor of geology at the University of Edinburgh in Scotland, John Flett. The other was a self-described “amateur of limited leisure,” Tempest Anderson. Anderson had been a physician who specialized in diseases of the eye. His interest in the human eye led him to study the new technology known as photography. (He made his own cameras and lenses.) And photography led him to search out and document what he regarded as nature’s most magnificent force—volcanic eruptions.

  His introduction to volcanoes came during a visit to the Eifel region of Germany where there are many extinct volcanic craters filled with picturesque lakes of water. That led him to see volcanoes in action, first to Vesuvius in 1883, then Etna the same year. Both volcanoes were in states of minor eruptions, small cones on each one spewing out small rains of cinders. From that time on, Anderson became a volcano-chaser, probably the first one in the world, dedicating himself to traveling at a moment’s notice to see and record, by writing descriptions and taking photographs, the great volcanic eruptions of the age. In fact, at his home in Edinburgh, he kept two suitcases packed, one with clothes for a cold climate and the other for a hot one, just in case he received news of an eruption somewhere in the world and he had to leave in a hurry.

  After recording the destruction by Soufrière on St. Vincent, Flett and Anderson sailed to Martinique. They were relaxing on a small sailboat, bobbing in a windless sea, one mile off the coast of St. Pierre on July 9 when Mount Pelée exploded.

  The two men happened to be discussing the possibility of climbing the volcano the next day when they saw a yellowish glow reflected off clouds hanging over summit. “It was like the lights of a great city on the horizon, or the glare of large iron furnaces,” Flett and Anderson wrote later.

  Then, from the volcano, they heard a “prolonged angry growl.” Instantly, the small cloud tumbled down the side of the volcano leaving a bright orange streak. The speed, as both Flett and Anderson would later attest, “was tremendous.”

  “It was a fear-inspiring sight,” wrote Anderson, “coming directly for us, where we lay with sails flapping idly as the boat gently rolled on the waves of the sea.”

  The boat’s crew, however, had been in a panic since seeing the initial yellowish glow. The men seized oars and rowed for their lives, but the boat was too heavy and awkward to move that way. Several members of the crew fell to their knees and started to pray. Flett and Anderson continued to watch, “overwhelmed by the magnificence of the spectacle.”

  Just as the rapidly descending cloud seemed ready to engulf them, the cloud’s front lost its downward momentum and rose into the air, passing directly over the boat. Now a hail of pebbles, some as large as chestnuts, began to fall on deck and into the sea. And that was followed by a rain of fine ash that lasted for more than an hour. Flett and Anderson realized they had witnessed at close range the deadly monster that had leveled St. Pierre.

  I can attest to the accuracy of their account because I saw a similar glowing cloud at a much later time at a different volcano. It happened in the spring of 1982 at Galunggung volcano on the island of Java.

  My Indonesian colleagues and I were three miles from the volcano. It was evening twilight and the eruption began, as it had for Flett and Anderson, with a faint yellowish glow reflected off a cloud hanging low over the volcano. Within seconds, a faint roar was heard. Next the glow started to pulsate, rising and falling in intensity. After a few cycles, a single explosion blew red and orange streamers into the air, their trajectories resembling the arcs made by ribs of an open umbrella. Darkness followed.

  Minutes passed. The glow returned to the crater, this time brighter than before. The roaring was louder. Then, as the glow continued to brighten, a flood of incandescent material, bright orange in color, sloshed up and over the crater rim. We watched in awe as it poured down the side of the volcano and toward us. We lost sight of the front as it passed on the opposite side of a low intervening ridge. The whole length of the ridge was silhouetted in light. It dimmed slowly.

  We were in darkness a second time. The roaring of the volcano continued, punctuated by deep detonations. Then there was another burst of the volcano, sending red and orange streamers higher than before. And from that rose a fountain of incandescent rock to heights of thousands of feet. And above the fountain was a pillar of smoke, the edges outlined by a clear night sky.

  The lightning and thunder display came next. It started directly over the volcano, and then spread across the sky. It was like standing under a bridge while huge trucks rolled overhead, sparks from the wheels sending out bolts and sheets of lightning.

  Next a hail of stones began to fall, followed, minutes later, by volcanic ash. It blocked out our view of the volcano. All we could hear was the roar.

  I had decades of work by other investigators to rely on when I saw my spectacle. Jaggar and Flett and Anderson were trying to understand a deadly phenomenon that, in their era, had barely been hinted at.

  What had propelled the glowing cloud down the side of Mount Pelée? Jaggar and Flett and Anderson attributed it totally to gravity, Flett and Anderson having described the movement of the cloud as similar to “a toboggan on a snow slide.” They were partially right. Gravity does play a major role in guiding such a cloud down the side of a volcano. But what of the tremendous speed? The cloud that had destroyed St. Pierre on May 8 had traveled four miles in about two minutes, an astonishing speed of more than a hundred miles an hour.

  The answer to this mo
re difficult question came soon. It came from someone else who arrived at Martinique to see the ruins of St. Pierre. But he would not uncover the answer until he made a grievous mistake.

  Alfred Lacroix had risen quickly to a position of prominence in French science. Having graduated with a doctorate degree in mineralogy in 1889 from the Muséum d’Histoire Naturelle in Paris, just four years later he was named the head of the mineralogy section at the museum. His meteoric rise was due, in part, to an extraordinary ability to study and describe and reveal the physical and chemical properties of minerals. And to the fact that he married the museum director’s daughter.

  The father-in-law, Ferdinand André Fouqué, is still regarded as one of France’s most accomplished geologists. In 1866 he had gone to Santorini in Greece after that volcanic island exploded. While there investigating the recent activity, he discovered an ancient city buried beneath more than a hundred feet of volcanic stones, cinders and ash erupted by previous eruptions. Those ruins are now thought to be the ancient city of Atlantis, a place that, according to the Greek philosopher Plato, “after a single day and night of misfortune” sank into the sea.

  As soon as news of the 1902 explosive eruption of Mount Pelée reached France, Fouqué asked his son-in-law to prepare a lecture about the geology of Martinique for members of the Muséum d’Histoire Naturelle. The lecture was presented on May 26. A week later, the first samples of new ash erupted from Mount Pelée arrived in Paris. Fouqué gave the samples to Lacroix who studied them for a week, who then gave a second lecture to museum members about what he had discovered. A third lecture was scheduled for late June in which Lacroix would compare his study of the 1902 samples with samples Fouqué had collected on his travels years earlier of the 1851 eruption. But, before the third lecture could be given, Fouqué raised a concern that, up to that time, only a team of American scientists was studying what had happened at St. Pierre. Martinique was a French colony. French science should be presented. And so the third lecture was postponed indefinitely. And Lacroix was sent to Martinique.

  He and two assistants arrived on Martinique on June 23. They tramped through St. Pierre, taking photographs. They interviewed survivors who, by this time, had told their stories dozens of times. In short, the French repeated what had already been done. But Lacroix did have the foresight to train two local French soldiers on the use of cameras and to station them on a small hill south of St. Pierre where there was a good view of the volcano. He drilled them endlessly on how to take a quick sequence of photographs until the two soldiers could take a photograph every ten seconds. Lacroix then left to tour other Caribbean islands and study their geology.

  On July 9, the two soldiers failed to respond fast enough to capture the beginning of the eruption on film, but they did succeed in photographing the ash cloud that sped down the volcano and toward St. Pierre. When Lacroix returned, he examined the photographs, seeing, for the first time, documented proof of the high speed of the cloud.

  On August 1, Lacroix departed the island and sailed back to France. Before he left he met with the French colonial governor and gave him his personal assurance that Mount Pelée was lessening in explosive activity and that the worse was over. That caused the governor to issue a directive that ordered everyone who had left their houses and were living in Fort-de-France—the number of refugees was in the tens of thousands—to return home or risk losing their food allowance. And so, many returned. Jaggar, learning of the directive, issued his own appraisal of the risk.

  “The mountain at this moment appears calm,” Jaggar wrote in a report that he sent to the colonial governor, “and the dust columns that one sees from time to time are largely due to landslides from the crater.” But, he cautioned, future eruptions, including a repeat of July 9, should be expected. Furthermore, he said that he was “strongly opposed” to the island’s government forcing people to return to their homes when, in his opinion, “the volcano is still dangerous.”

  Jaggar also identified the area of highest risk. “I do not think a single habitation northwest of the line from Bellafontaine to Basse-Pointe area safe.” That area covered almost the entire western half of Mount Pelée, which included St. Pierre. In addition, he thought towns located high on the volcano, such as Morne-Rouge, “are [not] safe at present.” At the end of the report, Jaggar rued the colonial government to establish “a properly equipped experiment station,” one that would have a permanent staff of scientists who could warn people of changing activity and imminent eruptions. Then, a few days after he released his report, Jaggar left and returned to Boston.

  Three weeks later, Mount Pelée exploded again.

  On August 25 an enormous cloud of ash spewed out of the volcano, the ash falling across the island. Many of those who had recently returned to their homes now retreated back to Fort-de-France. Some in Morne-Rouge—one of the places Jaggar had identified—stayed, seeking protection inside a stone church, the largest and sturdiest building in the small town, where Father Francis Mary welcomed them.

  The next day, Father Mary sent a delegation of citizens to Fort-de-France to ask the colonial governor for permission for the people of Morne-Rouge to leave and go to a safer place. The governor said no.

  On August 29, the ground at Morne-Rouge shook continuously. The next day, Mount Pelée exploded yet again, devastating an area twice as large as the one destroyed on May 8. During the explosion, Father Mary stood outside his church, holding the door open so that people could enter. An ash cloud, similar to the one that destroyed St. Pierre, swept over Morne-Rouge. Thousands died, including Father Mary.

  There were no recriminations within the colonial government in Fort-de-France or at the colonial office in Paris over the decision to deny permission for the people of Morne-Rouge to leave. Lacroix, however, may have felt a personal responsibility because, soon after he heard of the additional deaths, he sailed back to Martinique. This time he would stay six months—time well used in that he would finally determine what gave volcanic eruptions so much explosive force.

  The first person to see the odd feature on Mount Pelée was Thomas Jaggar. It was July 6, and he was back in St. Pierre, again surveying the ruins. For days, the summit of the volcano had been hidden by clouds, but on this morning, as he recorded it, “I had the good fortune to see the whole cone clear of clouds for about ten minutes.” During that brief time, he studied Mount Pelée through binoculars, seeing “a most extraordinary monolith” at the summit.

  It was shaped like the dorsal fin of a shark, smooth and slightly curved on one side, steep and with a slight overhang on the other. Three days later, after the July 9 eruption, he studied the summit again through binoculars. The moonlight was gone. But it reappeared a few days later.

  The second monolith was also destroyed, on August 30, by the same explosive eruption that sent an ash cloud over Morne-Rouge. After that, the intensity of explosions lessened, allowing a third monolith to grow. It was soon known as “the spine of Pelée.”

  It reached its broadest and highest dimensions in the spring of 1903 when the base was 500 feet across and the top towered nearly a thousand feet above what had been the summit. Seen during the day, it appeared as a great steaming obelisk. At night, it glowed a dull red. One captain whose ship passed it at night remembered it as “resplendently luminous.” But to the people of Martinique it was an eerie reminder of the tens of thousands of people who were dead. And for Lacroix it was the key to understanding why volcanoes explode.

  Lacroix returned to Martinique on October 1, focusing his attention on the growing monolith, studying it at close range. In his field notes, he recorded that the great obelisk changed color depending on the viewing angle. From one side it might appear deep brown, while from others pink or purple or nearly white. He measured and photographed it. At one point, comparing measurements on two successive days, he determined the top of the monolith was rising at the astonishing rate of forty feet a day.

  As the spine of Pelée grew, it maintained its original
basic shape, as described by Jaggar. One side was smooth, almost polished in places. It had long grooves, some of which began at the base and continued upward for hundreds of feet. It was the grooves that showed how malleable the surface must be. Lacroix likened them to the grooves one gets when applying thick paint.

  The other side was rough and had overhangs produced by frequent rockfalls. Occasionally, a rockfall was huge—and Lacroix witnessed several; he was frequently at the summit. And when such events happened, the entire side of the spine would collapse. Then a jet of hot gas would come roaring out from the base of the spine and send a mixture of ash and stone hurling part way down the volcano. It was this sequence that gave Lacroix the insight into volcanic explosions.

  As he described them, the ash clouds were “an intimate blend, a sort of emulsion, of solid materials suspended in water vapor and gas, carried together in a high temperature.” At the front of a cloud, as he observed in person, was a protruding tongue that always kept close to the ground. As he watched the tongue move, he realized it was not hurling down the volcano simply under the pull of gravity, but was being propelled forward by the constant expansion of gas—gas that had been dissolved in the rock at the base of the spine, then released suddenly during a collapse.

  In short, as Lacroix suddenly realized, the spine worked as a cork keeping a shallow batch of hot rock under pressure. When a side of the spine collapsed—that is, when a section of the cork was removed—pressure was released and gas bubbles formed instantly. Lacroix said it was much like the opening of a bottle of champagne—the same analogy Constant Prévost had used, though there is no evidence that Lacroix knew of his countryman’s earlier work.