Abstract: The beaches of the Cantabrian coast (northern Spain) are exposed to strong winter storms that
cause the coastline to recede. In this article, the coastal retreat of the Gerra beach (Cantabria) is analyzed
through a diachronic study using the following di erent geomatic techniques: orthophotography of
the year 1956; photogrammetric flights from 2001, 2005, 2010, 2014, 2017; Light Detection and Ranging
(LiDAR) survey from August 2012; Unmanned Aerial Vehicle (UAV) survey from November 2018;
and terrestrial laser scanner (TLS) through two dates per year (spring and fall) from April 2012 to
April 2020. With the 17 observations of TLS, di erences in volume of the beach and the sea cli are
determined during the winter (November?April) and summer (May?October) periods, searching their
relationship with the storms in this eight-year period (2012?2020). From the results of this investigation
it can be concluded that the retreat of the base of the cli is insignificant, but this is not the case for
the top of the cli and for the existing beaches in the Cantabrian Sea where the retreat is evident.
The retreat of the cli top line in Gerra beach, between 1956 and 2020 has shown values greater than
40 m. The retreat in other beaches of the Cantabrian Sea, in the same period, has been more than
200 m. With our measurements, investigations carried out on the retreat of the cli s on the Atlantic
coast have been reinforced, where the diversity of the cli lithology and the aggressive action of the
sea (storms) have been responsible for the active erosion on the face cli . In addition, this research
applied geomatic techniques that have appeared commercially during the period (1956?2020), such as
aerial photogrammetry, TLS, LiDAR, and UAV and analyzed the results to determine the precision
that could be obtained with each method for its application to similar geomorphological structures.
