Multitemporal Geomorphological Analysis of Beach-Cliff Systems in Seismic Zones: A Case Study of Manabi, Ecuador

Abstract

Coastal regions are increasingly recognised as prime locations for recreational tourism. Among these, the province of Manabi, Ecuador, with its distinct coastal cliff geomorphology, has considerable tourist appeal. However, a major seismic event in 2016, registering Mw 7.8, resulted in significant geomorphological alterations at the coastal level. This study sought to characterise the geomorphology of beach-cliff systems in Manabi province, utilising Geographic Information Systems (GIS) to identify the geomorphological changes induced by the 2016 earthquake, with the objective of informing sustainable management strategies. GIS was employed to discern the geomorphological alterations in the beach-cliff systems and compute their retreat rates. A Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis facilitated understanding of the current state of the cliffs, critical for devising coastal and tourism management strategies. The study area encompassed the beach-cliff systems of Canoa, Bahia de Caraquez, Crucita, Santa Marianita, San Lorenzo, and Los Frailes, with coastal, gravitational, and fluvial dynamics identified. Comparisons of pre- and post-earthquake conditions revealed notable changes, including surface flows and uplifts. Calculated cliff retreat rates (in m/year) yielded values of 0.76 (Canoa), 0.89 (Bahia), 1 (Crucita), 0.53 (Sta. Marianita), 0.83 (San Lorenzo), and 0.62 (Los Frailes). The study concludes with proposed strategies centred on political, scientific-academic, social, and tourism sectors to foster sustainable local development. These findings underscore the importance of comprehensive geomorphological assessment in the context of natural disasters, and its significance in informing management strategies for sustainable tourism and development.