title: Shipwrecking Probability in Mediterranean Territorial Waters. A Cultural Approach to Archaeological Predictive Modelling
Creators: name: Ritondale, Manuela 
Publisher: name: IMT Alti Studi Lucca
Year: 2022

description: This thesis presents a formal approach and a GIS-based methodology for the assessment of the shipwrecking probability in Mediterranean territorial waters, thus addressing the underdevelopment of archaeological predictive models in the maritime domain, particularly in the Mediterranean region. As archaeological predictive models are often criticized for oversimplifying complex historical phenomena to produce quantifiable outcomes, this study focuses on two different scales of analysis to meet the need for both a general tool applicable to spatial planning and a more detailed one providing insights for historical and archaeological research. First, a regional-scale model is developed, which focuses on navigation dynamics in the area between Cap Bon (present Tunisia) and Alexandria (present Egypt) in Roman times. Then, this model is extended to all Mediterranean territorial waters in a simplified version and without chronological limitations. At both scales, the criteria for selecting the input factors are formalized. In order to identify areas with higher shipwrecking probability than others, two sub-questions are addressed that correspond to separate model components: 1. Where would ships be more likely to transit? 2. Where would ships have a higher risk of sinking? Grounding the theory-building on a systematic screening of accounts by primary sources, the first model component derives transit probabilities by considering multiple, oftentimes competing, criteria that trigger and affect mariners’ movements, including in particular the effects of risk perception - thus rejecting the idea that sailors would necessarily choose the optimal or most efficient route. The second model component includes environmental hazards objectively increasing the risk of sinking. Given the many elements of uncertainty and subjective reasoning behind the model building - a problem often unheeded in archaeological computational modelling - an entire chapter is devoted to a sensitivity analysis of the model and the exploration of diverse model scenarios. The overall methodology attempts to overcome some of the main pitfalls of current modelling approaches to seafaring and to shipwreck locations, namely, the inductive use of shipwreck data without a formal exploration of data biases, and the predominant reliance on environmental and economic input variables to the detriment of cultural and cognitive factors. This study suggests that by explicitly differentiating between actual and perceived risks, and accounting for the effects this difference produces in terms of variations from the optimal navigation corridors, the predictive ability of the model increases. While constituting a valuable tool for optimizing maritime spatial planning and archaeological investigations, this model also offers insights into the biases in current shipwreck data. The model furthermore provides an adaptable toolkit applicable to other geographical contexts and chronological periods, and a suitable basis for expansion with a future component by modelling post-depositional dynamics that affect the preservation and detectability of wrecks at local scales.