Abstract:

During the Plinian eruption of Somma-Vesuvius in AD 79 almost the entire Sarno River Plain (Campania, Italy) was more or less instantly covered by thick volcanic deposits. This contributed to a good preservation of the palaeo-surface and the palaeo-environmental conditions before AD 79. Since the AD 79 volcanic deposits can be clearly distinguished from other stratigraphic layers they can be considered as a chronostratigraphic marker for identifying the pre-AD 79 palaeo-surface in the Sarno River Plain. The objective of this geoarchaeological study was to reconstruct the pre-AD 79 topography and selected palaeoenvironmental features of the Sarno River Plain by modelling the thickness of the post-AD 79 deposits. Thus a methodology was developed that is based on an extensive dataset of stratigraphic information, a highresolution present-day digital elevation model (DEM) and a classification and regression tree approach.

Key Words: Paleo-Landscape Reconstruction, Classification and Regression Trees, Predictive Modelling, Sarno River Plain, Pompeii

Introduction

The eruption of Somma-Vesuvius AD 79 is one of the most well known explosive volcanic eruptions in antiquity, above all thanks to the detailed written records of Pliny the Younger. This eruption can be considered a caesura in the existence of an entire landscape since the entire Sarno River Plain besides Pompeii and Herculaneum was buried by pumice fallout and pyroclastic surge deposits. These deposits reached a total thickness of approximately 3.4m (mean and median, determined from 1,236 stratigraphic drillings) ranging from 0.4m to 7.8m (95% confidence interval). Since the deposits of AD 79 are laterally extensive and show a characteristic stratigraphy they can be considered as a chronostratigraphic marker for the identification of the Roman surface before AD 79. Consequently, today, almost 2000 years after, it is still possible to study the Roman surface by means of stratigraphic investigations, which allows us to reconstruct the pre-AD 79 topographic conditions. Furthermore, the character of the Roman stratum provides information about important palaeo-environmental landscape features of the Sarno River Plain before AD 79. The objective of this project is to generate a high-resolution digital elevation model (DEM) of the Sarno River Plain and reconstruct some palaeo-environmental conditions before the eruption of Somma-Vesuvius AD 79. This pre-AD 79 DEM will be the basis for further geoarchaeological research in this area aiming at comprehensively studying the relationship between ancient people and their environment in the hinterland of Pompeii.