Recent geological and archaeological investigations in Chalchuapa, El Salvador, together have provided the probable answer to a question which has long puzzled students of the history of the Maya.

The question: Why are there throughout the Maya area numerous instances of the sudden appearance of a full-blown Maya Protoclassic civilization, whereas a more normal, progressive development of the Protoclassic is found at other sites?

The evidence: Geologists have discovered that there was a violent eruption of Ilopango Volcano in approximately the second century A.D., which deposited a thick layer of volcanic ash over much of the surrounding countryside, making hitherto productive farm lands unusable. Archaeologists have found such a layer of ash immediately overlying the Protoclassic strata at Lake Cuzcachapa and elsewhere in Chalchuapa.

The answer: After the eruption, the area could not sustain its entire population and there­fore groups of Protoclassic people emigrated to sites where they might hope to establish new homes.

During the past few years the University Museum has been excavating at Chalchuapa under the direction of William R. Coe and Robert J. Sharer, focusing its attention on what happened in that area during a 2500-year time span, beginning before 1000 B.C. and leading up to the Spanish Conquest by Alvarado in 1524.

The earliest sedentary peoples occupying the Chalchuapa area evidently were an extension of the general lowland early agricultural societies who inhabited the Pacific littoral of Guatemala and the tropical lowland areas of southern Mexico. Between 900 and 500 B.C. the influence of the precocious Olmec state waxed and waned, leaving evidence of its presence in terms of pottery, monumental bas-relief sculpture, and figurines. During the succeeding six or seven centuries, Chalchuapa was a part of the general cultural evolution of the Guatemalan highlands.

By the first century A.D., El Salvador appears to have been densely settled, with the major ceremonial centers and sustaining populations located in the middle of broad, fertile, alluvial valleys. The term “Protoclassic” is used in this article to denote a particular complex of formal and stylistic attributes which are characteristic of El Salvador at this time, although the term was first defined elsewhere. (See Expedition, Winter 1969.)

The hallmark of the Protoclassic is a shallow bowl with an outcurved rim and four bulbous feet, generally called a mammiform tetrapod on a Z-angle bowl. Other elements of the Protoclassic include a proliferation of Usulutan decorative techniques, orange monochrome pottery, a painted post-firing white slip. potstands, and other artifacts and techniques beyond the scope of this article. The gradual development of this package of traits was unveiled by excavations conducted by Bruce Anderson in finely-stratified deposits on the shore of Lake Cuzcachapa in Chalchuapa, immediately overlying the uppermost levels containing the Protoclassic at Lake Cuzcachapa and elsewhere in Chalchuapa is a layer of volcanic ash. Its placid appearance—it looks like a fine-grained beach sand—belies the violence of the eruption which deposited it, and what it would have been like to have experienced such an event. An inkling of what this eruption may have been like may be gained from the eyewitness account of a similar but less violent eruption in 1835. Vicente Romero, the Commandant of the Salvadorian port of La Union, describes the eruption of nearby Coseguina Volcano, in Nicaragua:

On the 20th (January 1835), the day having dawned with the usual serenity, at 8 o’clock, towards the southeast, a dense cloud was per­ceived of a pyramidal figure, preceded by a rumbling noise, and it continued rising until it covered the sun, at which elevation, about 10, it separated to the north and south accompanied by thunder and lightning; the cloud finally covered the whole firmament, about 11, and enveloped everything in the greatest darkness, so that the nearest objects were imperceptible. The melan­choly howling of beasts, the flocks of birds of all species, that came to seek, as it were, an asylum amongst men, the terror which assailed the latter, the cries of women and children, and the un­certainty of the issue of so rare a phenomenon, everything combined to overcome the stoutest soul and fill it with apprehension, and the more so when at 4 P.M., the earth began to quake and continued in a perpetual undulation which generally increased.

This was followed by a shower of phos­phoric sand, which lasted until 8 P.M., on the same day, when there began a heavy fail of a fine powder-like flour. The thunder and lightning con­tinued the whole night and the following day (the 21st), and at eight minutes past 3 P.M. there was so long and violent an earthquake that many men, who were walking in a penitential procession, were thrown down. The darkness lasted forty-three hours, making it indispensable for everyone to carry a light, and even those were not sufficient to see with.

On the 22nd it was somewhat less dark, although the sun was not visible. And towards the morning of the 23rd, the tremendously loud thunder claps were heard in succession like the firing of pieces of artillery of the largest calibre, and this fresh occurrence was accompanied by increased showers of dust.

From dawn of the 23rd until 10 A.M., a dim light only served to show the most melancholy spectacle. The streets which, from the rocky nature of the soil are full of inequalities and stones, appeared quite level, being covered with dust. Men, women and children were so disfigured that it was not easy to recognize anyone except by the sound of their voices or other circum­stances. Houses and trees, not to be distinguished through the dust which covered them, had the most horrible appearance, yet in spite of these appalling sights, they were preferable to the darkness into which we were again plunged from after the said hour of 10, as during the preceding days.

The general distress, which had been assuaged, was renewed and although leaving the place was attended by imminent peril from the wild beasts that sallied forth from the forests and sought the towns and the high roads (as happened in the neighboring village of Conchagua and this town), into which tigers ( jaguars) thrust themselves; yet another terror was superior, and more than half the inhabitants of Union emigrated on foot, abandoning their houses, well persuaded that they should never return to them; since they prognosticated the total destruction of the town, and fled with dismay for refuge to the mountains.

At half past 3 on the morning of the 24th, the moon and a few stars were visible, as if through a curtain, and the day was clear although the sun could not be seen, since the dust continued falling, having covered the ground all around to a thickness of five inches (13 cm.).

The 25th and 26th were like the 24th, with frequent though not violent earthquakes . . . and the showers of dust lasted till the 27th.