The Wonder Book of Volcanoes and Earthquakes

CHAPTER XI

Chapter 111,835 wordsPublic domain

THE CATASTROPHE OF MARTINIQUE AND THE VOLCANIC ISLANDS OF THE LESSER ANTILLES

The West Indies Island chain consists of two groups of islands; i. e., the Greater Antilles, including Cuba, Jamaica, Hayti, and Porto Rico, on the west, and the chain of the Lesser Antilles on the east.

The Lesser Antilles consists of two parallel chains, the westernmost of which is for the greater part mountainous with peaks several thousand feet in height. All these islands are volcanic. The chain on the east consists of low, calcareous rocks, or rocks consisting largely of lime.

In the western chain the islands beginning on the south are, Grenada, St. Vincent, St. Lucia, Martinique, Dominica, Guadeloupe, Montserrat, Nevis, and St. Eustace, while in the calcareous chain are found the Tobago, Barbadoes, and others.

Prior to 1902, the greatest volcanic eruption in this part of the world occurred on the island of St. Vincent, with the volcano of Soufrière. Although the forces displayed were exceedingly great, yet they become insignificant when compared with the appalling eruption that took place in Martinique only a short time ago; namely, May the 8th, 1902, when the volcano of Mt. Pelée, situated on the northwestern part of the island, burst into an eruption so terrible that in destruction of life it far exceeded the eruption of Krakatoa, although the amount of energy causing the eruption was much smaller.

Heilprin, in a book called "Mt. Pelée and the Tragedy of Martinique," from whom most of the information of this chapter has been obtained, calls attention to the fact that before the eruption of Pelée there were plenty of warnings for those intelligent enough to note them. For two or three weeks prior to May 8th, 1902, the volcanic activity of Pelée had been rapidly increasing, the mountain throwing out clouds of ashes and sulphurous vapors from its crater. By April 25th the sulphurous vapors had so increased in quantity as to make breathing difficult in St. Pierre. The ashes fell on the surrounding country and by the 2d of May had so covered the streets of St. Pierre as to stop traffic.

Three days later, May 6th, shortly before noon, an avalanche of mud poured down the slopes of the mountain with the rapidity of an express train. These torrents of mud and water deluged the towns and villages in the neighborhood. The activity of Mt. Pelée increased until the morning of May 8th, 1902, when, almost at exactly 8 A. M., an eruption occurred, so terrible in its effects that in two minutes the city of St. Pierre was almost completely destroyed.

St. Pierre, the principal town of Martinique, is situated on the island of Martinique, on the northwestern coast, about ten miles southwest of Mt. Pelée. St. Pierre was settled as far back as 1635. It is situated on an open roadstead without any harbor.

That there were many points of resemblance between the position of St. Pierre and the destroyed city of Pompeii will be recognized as the description of the catastrophe is given.

St. Pierre was a beautiful city, and formed the natural outlet to one of the richest districts in Martinique for the production of sugar cane and cocoa. It contained many fine houses, the homes of planters, wealthy bankers, merchants, and shippers, who, besides their regular houses in the city, had constructed handsome villas on heights on the outskirts of the city. The houses were to a great extent one or two stories in height, and were in many cases surrounded by fine gardens. The city extended along the coast for about two miles. The streets were well lighted.

The eruption of Mt. Pelée on May 8th, 1902, was of a very unusual character, containing a feature that--with the exception of a volcanic eruption of Soufrière, a volcanic mountain on the neighboring island of St. Vincent, and an eruption of Kilauea in Hawaii--so far as I am aware, never before occurred. This was a blast of highly heated air, mingled with white hot or incandescent dust, that swept down the side of the mountain with a velocity of one or two miles per minute, or possibly more.

Nearly all of the people in St. Pierre were killed. From the appearance of the bodies it seemed that death was practically instantaneous, and was due either to scorching or burning, or asphyxiation by the breathing of highly heated air. The number of people so killed, including almost the entire population of St. Pierre, as well as a number of adjoining settlements, was not less than 30,000.

The zone of absolute destruction was limited to an area the extent of which did not greatly exceed eight or nine square miles. On the outskirts of this zone the destruction, though considerable, was less complete.

There was almost an entire absence of great earthquake shocks during the eruption.

Following the terrible eruption of May 8th were a number of less violent eruptions on May 20th, 26th, June 6th, July 9th, and August 31st. According to Heilprin these eruptions were of the same character as that of May 8th.

There has been considerable discussion as to the exact causes of the tornadic incandescent blast that caused the awful destruction of life. Without entering this discussion it is sufficient to say that it is now generally considered that the blast consisted of highly heated air, and super-heated steam loaded with great quantities of finely divided red hot or even white hot dust particles.

While, perhaps, the force producing the awful eruption of Mt. Pelée was greatly excelled in the case of many other volcanic eruptions; such as Papandayang, in 1772; Asamayama, in 1783; Skaptar Jökul, in 1783; Tomboro, in 1815; Coseguina, in 1835; and Krakatoa, in 1883; yet, in the words of Heilprin, "in intensity and swiftness of its death-dealing blast ... the eruption of May 8th, and of later dates, stands unique in records of volcanic manifestations."

While the amount of ashes that accompanied the blast of white hot steam and air was comparatively small, yet during the time between this and the subsequent eruptions, the amount of ashes that were thrown from the surface of Mt. Pelée was exceedingly great.

According to Russell, in a paper on the volcanic eruptions of Martinique and St. Vincent, in 1902, the amount of ashes and solid matter generally thrown out from the crater of Mt. Pelée would be equal to 40,000,000 cubic feet every minute, or one and a half times the sediments discharged by the Mississippi in the course of a whole year.

According to Heilprin, however, the actual amount of dust thrown from the crater of Mt. Pelée was, probably, 500 times greater than the amount discharged by the Mississippi River in the course of a year, and, consequently, considerably greater than that of all the rivers of the world combined, or, as he says:

"Mont Pelée has now been in a condition of forceful activity for upwards of two hundred days; can we assume that during this time it may have thrown out a mass of material whose cubical contents are hardly less than a quarter of the area of Martinique as it now appears above the waters? One is, indeed, almost appalled by the magnitude of this work, and yet the work may even be very much greater than is here stated. We ask ourselves the questions, what becomes of the void that is being formed in the interior? What form of new catastrophe does it invite? There can be no answer to a question of this kind--except in the future happening that may be associated with this special condition. But geologists must take count of the force as being one of greatest potential energy, whose relation to the modelling and the shaping of the destinies of the globe is of far greater significance than has generally been conceived."

A curious circumstance connected with the eruption of Mt. Pelée was the most pronounced electric and magnetic disturbances. Moreover, as in the case of the eruption of Krakatoa, there were the same after glows or red sunsets and sunrises due to the presence of fine volcanic dust in the higher regions of the air. These phenomena were observed over widely separated areas.

It appears that this great eruption in Martinique was preceded by severe earthquakes in the northern part of South America, especially in Colombia and Venezuela. The most marked was the great earthquake which on April 18th destroyed the city of Guatamaula; this was, perhaps, the most destructive earthquake that has occurred in the Western Hemisphere since the great earthquake of 1812, that destroyed the city of Caracas. Indeed, Professor Milne suggests that it was this earthquake that brought about the eruption of Mt. Pelée.

Soufrière, on the island of St. Vincent, had a great eruption on May 7th, 1902, one day before the awful eruption of Mt. Pelée. No lava flowed during this eruption. There were, however, great discharges of mud, due to a lake that before the eruption filled the top of a depression known as the old crater which lay southwest of a new crater, or the crater that was formed during the eruption of 1812. The old crater was nine-tenths of a mile across from east to west, and eight-tenths of a mile from north to south. The depth to the crater floor was from 1,000 to 2,400 feet. The surface of the new and shallow boiling lake which occupied the deepest part of the floor during the latter part of May, and from June to August, was estimated to be only 1,200 feet above the level of the sea. The sheet of water that occupied it before the eruption being several hundred feet higher.

Soufrière did not fail to give warnings of its coming eruption. Rumblings were heard two days before the explosion. On May 5th, 1902, fishermen who crossed the lake noticed that the water was disturbed and agitated. On the Tuesday following, May 6th, great clouds were thrown out during the afternoon, and the volcano was illumined by a reddish glare of fire. The first explosion was heard shortly before two o'clock on the following day and the volcano burst into activity. The explosions, together with great discharges of pumice, ashes, and boulders, followed one another rapidly. A column of steam was shot up into the air for a height of 30,000 feet. The severest paroxysm came shortly after ten A. M., and was succeeded by others nearly as violent during the next few hours. By this time a reddish curtain of clouds nearly shut out the island from view, and rapidly advanced over the land and descended on the sea. This eruption caused a loss of life of about 1,350.

This eruption of Mt. Soufrière was accompanied by the same tornadic blast of glowing air. There was not, however, any single blast quite as severe as that which attended the eruption of Pelée on May 8th, 1902.