Morphometric Characterization of a Prominent Linear Bathymetric Anomaly in the Tyrrhenian Sea

This report presents the discovery and detailed morphometric characterization of a major linear anomaly on the seafloor of the Tyrrhenian Sea, identified during a 2021 analysis of the public Digital Terrain Model (DTM) from the EMODnet Bathymetry portal.

https://zenodo.org/records/15851033

The feature is an exceptionally straight track extending for a total length of approximately 52.5 km. It is characterized by a complex, two-component structure:

1. A core linear track, with a width varying between 840 meters and 1 kilometer, which presents a distinct “trench and berm” morphology (a central depression flanked by parallel, low-relief ridges).
2. A broader corridor of disturbed seafloor morphology, ranging from 4.6 to 6.2 kilometers in width, which envelops the central track.

The extreme linearity and geometric regularity of the feature make a natural geological origin highly improbable. The evidence strongly suggests an anthropogenic origin, hypothesized to be either a data-integration artifact resulting from the merging of a high-resolution survey swath into a lower-resolution regional grid, or the physical trace of a submarine infrastructure corridor (such as a telecommunications cable or pipeline). The paper discusses the possibility that the feature is a combination of both a physical seafloor modification and a digital artifact emphasized by the gridding process.

This work provides the first formal documentation, precise location (centered near 42.351°N, 11.200°E), and morphometric measurements of this uncatalogued feature. It serves as a practical case study for marine geoscientists, geographers, and data analysts on the critical interpretation of large-scale, composite datasets and highlights the potential for such public-domain data to contain significant, unannotated features of anthropogenic origin.

Keywords:
Bathymetry, Marine Geomorphology, Seafloor Mapping, Linear Anomaly, Tyrrhenian Sea, Italian Continental Shelf, EMODnet, Digital Terrain Model (DTM), Anthropogenic Feature, Data Artifact, Submarine Cable, Pipeline, Case Study, Data Interpretation.