Coastal erosion is a common phenomenon along the world’s coasts. Studying it is complex because such studies must cover large portions of land, and it is necessary to understand the multiple processes that interact in each area, so it is important to recognize regional patterns that allow for defining representativeness in relation to the surrounding dynamics. Spatial statistics can be used in coastal geomorphology to identify and quantify trends in coastal morphodynamics. This study analyzes and interprets the spatio-temporal patterns present in the changes in a shoreline, that is, the processes of erosion and coastal sedimentation in the Pacific and the Colombian Caribbean. The results are derived from the detection of significant changes in the coastline via satellite images. For this study, the shoreline of Colombia was digitized for the years 1986 and 2016, thus obtaining changes in the shoreline at a medium temporal scale. The Global Moran’s Index, Local Moran’s Index and Getis–Ord Index were used to explain the spatial statistics. The Global I Moran values for the Pacific were I = 0.190, z = 31.063 and p = 0.01, and for the Caribbean I = 0.624, z = 74.545 and p = 0.01, which suggests good grouping in the Caribbean and very low grouping for the Pacific. The local indices (Moran’s and Getis–Ord) allowed us to visualize and spatialize the significant points of coastal erosion and sedimentation. According to the results, three conceptual models are herein proposed that relate the indices with the geomorphological characteristics: (a) the greater the geomorphological heterogeneity, the greater the grouping; (b) the greater the geomorphological homogeneity, the lower the degree of clustering; (c) the greater the geomorphological complexity, the lower the degree of clustering. Finally, it is confirmed that coastal erosion and sedimentation processes predominate along low coasts.

A hazard and vulnerability assessment of coastal erosion is an essential first step for planning and decision-making, because it is part of risk management and its results are in the form of easily interpreted traffic-light maps. For the analysis of the assessment in this work, a methodology is proposed which considers three components for both hazard (magnitude, occurrence, and susceptibility) and vulnerability (exposure, fragility, and lack of resilience), through a semi-quantitative approximation, by applying relative indices to different variables. This methodology has been adapted to analyze hazards and vulnerability caused by coastal erosion combining physical and social aspects. For the validation of this methodology, Spratt Bight Beach (Colombian Caribbean) and La Bocana beach (Colombian Pacific) were selected in order to have contrasting regions and to validate the application of the method over a geographical range. One of the most significant outcomes of the assessment of the degree of hazard and vulnerability is that the rating may represent different combinations of factors. It is therefore important to study and interpret the components separately, allowing us to propose corrective and/or prospective focused interventions at local and regional levels. In terms of vulnerability, the assessment highlighted the importance of cultural ecology as a factor of resilience to coastal hazards.

In the town of La Barra, Buenaventura (Colombia), since 2013, it started a process of avulsion towards the sea of the Arrastradero tidal channel (estero), associated with this event, an accelerated process of coastal erosion that affected the town in general was measured. In order to test the hypothesis that coastal dynamics determines not only the morphology of the coast but also the population dynamics, vulnerability by coastal erosion of the population was assessed, the historical and recent evolution of the coastline and the littoral spit and also the evolution in the location of houses. It was determined that before the current erosion phenomenon the area had already undergone several processes of change, which impacted the population dynamics. During the study period (2013 to 2015), the months of greatest change in the coastline were between March and May 2014, this being the year of greatest decline. Additionally, associated with these changes, the vulnerability of the population increased from 2013 to 2014. Finally, it can be concluded that an important adaptation value of Afro-descendant communities in the Pacific to coastal risks is the collective thinking and its ancestral practices, that mark its mobility around the natural dynamics of their environment, making them more resilient, that is, culture as a strategy of adaptation to the environment (cultural ecology). En el poblado de La Barra, Buenaventura (Colombia), desde el año 2013 inició un proceso de avulsión hacia el mar del estero Arrastradero, asociado a este evento se pudo medir un acelerado proceso de erosión costera que afectó el poblado en general. Con el fin de comprobar la hipótesis de que la dinámica litoral determina no solo la morfología de la costa sino también la dinámica poblacional, se evaluó la vulnerabilidad por erosión costera de la población, la evolución histórica y reciente de la línea de costa y de la espiga litoral y la evolución en la localización de las viviendas. Se determinó que antes del fenómeno de erosión actual la zona ya había sufrido varios procesos de cambio, que impactaron la dinámica poblacional. Durante el periodo de estudio (2013 a 2015), los meses de mayor cambio en línea de costa fueron entre marzo y mayo de 2014, siendo este el año de mayor retroceso. Adicionalmente, asociado a estos cambios, la vulnerabilidad de la población se incrementó de 2013 a 2014. Finalmente, se puede concluir que un importante valor de adaptación de las comunidades afrodescendientes del Pacífico a los riesgos costeros, es el pensamiento colectivo y sus prácticas ancestrales que marcan su movilidad alrededor de las dinámicas naturales de su entorno, haciéndolas más resilientes, es decir, cultura como estrategia de adaptación al medio (ecología cultural). In the town of La Barra, Buenaventura (Colombia), since 2013, it started a process of avulsion towards the sea of the Arrastradero tidal channel (estero), associated with this event, an accelerated process of coastal erosion that affected the town in general was measured. In order to test the hypothesis that coastal dynamics determines not only the morphology of the coast but also the population dynamics, vulnerability by coastal erosion of the population was assessed, the historical and recent evolution of the coastline and the littoral spit and also the evolution in the location of houses. It was determined that before the current erosion phenomenon the area had already undergone several processes of change, which impacted the population dynamics. During the study period (2013 to 2015), the months of greatest change in the coastline were between March and May 2014, this being the year of greatest decline. Additionally, associated with these changes, the vulnerability of the population increased from 2013 to 2014. Finally, it can be concluded that an important adaptation value of Afro-descendant communities in the Pacific to coastal risks is the collective thinking and its ancestral practices, that mark its mobility around the natural dynamics of their environment, making them more resilient, that is, culture as a strategy of adaptation to the environment (cultural ecology).