From Denver, at a meeting of the Geological Society of America
Recent excavations reveal that the ancient city of Pompeii, famed for its burial by an eruption of Italy’s Mount Vesuvius in A.D. 79, suffered through several devastating landslides in the centuries preceding its volcanic demise.
About three-fourths of Pompeii has been excavated, says Jean-Daniel Stanley of the National Museum of Natural History in Washington, D.C. However, most of the digs in the city have extended down only to the ground level of dwellings that were standing in the 1st century. In the past couple of years, deeper digs in the oldest part of Pompeii—as well as core drilling nearby—have exposed layers of jumbled sediment that suggest that the city was hit by other natural disasters prior to the A.D. 79 eruption.
At least three different sheets of sediment lie atop lava bedrock beneath the city. Those strata include shards of pottery, animal bones, and bits of plants. Carbon dating of the plant fragments hints that the lowest layer was deposited in the 8th century B.C., soon after the city was founded, says Stanley. The other two layers, separated from other strata by well-developed soil layers or Roman pavements, were laid down in the 4th century B.C. and the 2nd century B.C.
The jumbled sediments probably represent landslide deposits—possibly ones triggered by extended rainfall, says Stanley.
At least one of Pompeii’s purported landslides, the one in the 4th century B.C., would have occurred when the local climate was wetter than average, notes Stanley.