Abstract

In recent years, coastal erosion has increased worldwide related to the higher frequency and intensity of storm events, making these areas multi-hazardous [1]. The beaches of the Valparaíso region have undergone major changes due to extreme events, such as earthquakes, tsunamis, tidal waves, and anthropogenic activities [2]. Currently, the erosive processes present on some of its beaches are significant, with rates exceeding -1.5 m/yr., contributing to the degradation of the landscape [3]. In the Algarrobo bay, there have been major changes in the morphology of the beach, with direct effects on urbanized sectors such as San Alfonso del Mar. Showing erosion processes caused by waves. On the other hand, the coastal front of Viña del Mar constitutes a national and international tourist pole that has been affected by various extreme events, with direct impacts on the infrastructure near the beaches [4] (Figure 1). This paper analyses the Spatio-temporal changes caused by erosion on Algarrobo and Viña del Mar beaches between 1986 and 2020 considering the three drivers of erosion over the last 35 years. For this purpose, the shoreline was separated into three main periods: (i) before the earthquake of February 27, 2010 and covering 25 years of beach analysis (1985-2010); (ii) after the earthquake (2010-2015); and (iii) between 2015-2020, a period in which there was a marked increase in frequent and intense swells in the summer season.