This paper demonstrates that accurate data concerning bathymetry as well as environmental conditions in shallow waters can be acquired using sensors that are integrated into the same marine vehicle. An open prototype of an unmanned surface vessel (USV) named MicroVeGA is described. The focus is on the main instruments installed on-board: a differential Global Position System (GPS) system and single beam echo sounder; inertial platform for attitude control; ultrasound obstacle-detection system with temperature control system; emerged and submerged video acquisition system. The results of two cases study are presented, both concerning areas (Sorrento Marina Grande and Marechiaro Harbour, both in the Gulf of Naples) characterized by a coastal physiography that impedes the execution of a bathymetric survey with traditional boats. In addition, those areas are critical because of the presence of submerged archaeological remains that produce rapid changes in depth values. The experiments confirm that the integration of the sensors improves the instruments’ performance and survey accuracy.

Naples and its surroundings are a very young landscape, originated from 40 ka in response to strong and explosive volcanic processes, which created the Campi Flegrei, one of the largest volcanic fields of the world. Despite the repeated and continuous volcanic activity, this territory was selected for human settlements since Neolithic times and hosted some of the most important Greek and Roman towns in the Mediterranean area (e.g., Cuma, Parthenope, Neapolis, Baia and Puteoli). Geoarcheological data and historical chronicles testify to human coexistence with eruptions, bradyseismic ground motions, coastline changes, floods and landslides. With the aim of describing the geomorphological evolution of this area to a wide audience, including also non-experts, we constructed a synthetic geomorphological map of the area and sketches that synthesise the main stages of the geomorphological evolution of the historical centre of Naples and the coastal belt of the Gulf of Pozzuoli during the last millennia.

This paper shows an interesting case of coastal landscape reconstruction by using innovative marine robotic instrumentation, applied to an archaeological key-site in the Campi Flegrei (Italy), one of the more inhabited areas in the Mediterranean during the Roman period. This active volcanic area is world famous for the ancient coastal cities of Baiae, Puteoli, and Misenum, places of military and commercial excellence. The multidisciplinary study of the submerged Roman harbour at Nisida Island was aimed at reconstructing the natural and anthropogenic underwater landscape by elaborating a multiscale dataset. The integrated marine surveys were carried out by an Unmanned Surface Vehicle (USV) foreseeing the simultaneous use of geophysical and photogrammetric sensors according to the modern philosophy of multi-modal mapping. All instrumental measurements were validated by on-site measurements performed by specialised scuba divers. The multiscale analysis of the sensing data allowed a precise reconstruction of the coastal morpho-evolutive trend and the relative sea level variation in the last 2000 years by means of a new type of archaeological sea-level marker here proposed for the first time. Furthermore, it provided a detailed multidimensional documentation of the underwater cultural heritage and a useful tool for evaluating the conservation state of archaeological submerged structures.

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.