Ancient Coastal Changes Due to Ground Movements and Human Interventions in the Roman Portus Julius (Pozzuoli Gulf, Italy): Results from Photogrammetric and Direct Surveys

Pietro P C Aucelli,Aldo Cinque,Gaia Mattei,Claudia Caporizzo,Michele Stefanile,Francesco Peluso,Gerardo Pappone,Salvatore Troisi

doi:10.3390/w12030658

Pietro P C Aucelli, Aldo Cinque + Show 6 more

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https://doi.org/10.3390/w12030658

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Abstract

This research aims to evaluate the amount of vertical ground movements during Roman times inside the archaeological area of Portus Julius (Gulf of Pozzuoli) using high-precision surveys on the most reliable archaeological sea-level markers. Measuring the submersion of ancient floors, structural elements belonging to a former fish tank, and several roman pilae, two different relative sea levels (RSLs), related to the beginning and the end of the first century BCE, respectively, −4.7/−5.20 m and −3.10 m MSL (mean sea level), were detected. A photogrammetric survey was carried out in order to produce a 3D model of the fish tank. The results in terms of the RSL variations have enabled us to reconstruct a morpho-evolution of the ancient coastal sector during the last 2.1 kyBP. At the beginning of the first century BCE, the area was characterized by a sheltered gulf with numerous maritime villae located along the coast. In 37 BCE, the construction of the military harbour of Portus Julius strongly modified the paleogeography of the sector, which was also affected by a prevailing subsidence at least until the end of the first century BCE (year 12 BCE), when the port was converted into a commercial hub.

Highlights

The purpose of this study is to present the results of high-precision surveys on the most reliable archaeological markers of the ancient sea level, aimed at the evaluation of the ground movements affecting the area of Portus Julius during the Roman period
The third marker is is a floor belonged to a maritime villa built on the ancient sandy coast, considered a terrestrial a floor belonged to a maritime villa built on the ancient sandy coast, considered a terrestrial limiting point (TLPs), intended as a marker positioned above the ancient sea level [70]
The survey involved an area near to Portus Julius but already existing before its construction, where a maritime villa was built at the end of the Republican Age (I century BCE)

Summary

Introduction

The study of past geomorphological events may reveal the vulnerability of a specific area to dangerous phenomena, even if they have very long return times and/or very slow rates of action [1].such studies are fundamental to build site-specific process response models, which are useful to predict the consequences of future environmental changes (climatic, tectonic, etc.) [2,3,4].Regarding particular volcanic coastal areas, vertical ground movements and related changes of the relative sea level [5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20] represent crucial information for hazard forecasting based on the style and rate of landscape changes over the time.The present study concerning the Gulf of Pozzuoli, located in the wide caldera of the CampiFlegrei volcanic complex The study of past geomorphological events may reveal the vulnerability of a specific area to dangerous phenomena, even if they have very long return times and/or very slow rates of action [1]. Such studies are fundamental to build site-specific process response models, which are useful to predict the consequences of future environmental changes (climatic, tectonic, etc.) [2,3,4].

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