STUDY AREA

 

The Canaries are composed of seven islands in two regions: occident (Tenerife, La Palma, El Hierro and La Gomera) and oriental (Gran Canaria, Fuerteventura and Lanzarote). Additionally, other small islands in the oriental region are located in the North of Lanzarote and Fuerteventura. The islands are over the African plate, in the North of Africa, in front of the coast of Sahara and Morocco between coordinates 27º 37' and 29º 25' of north latitude and 13º 20' and 18º 10' of west longitude (GEVIC, 2014).

 

The climate of the Canary Islands is constant due to the influence of trade winds. These islands are considered as subtropical although altitude and slope have an important role in the local climate variations (Dorta, 1996).

 

According to Carracedo et al. (2008), the islands have an organization west to east in function of the age of the different islands, but historic volcanic activity2 is very relevant in the landscape of the older islands, such as Lanzarote in Timanfaya. Therefore, the recent activity is in the occident islands for example the recent volcanic activity3 in El Hierro the last year (IGN, 2014).

 

There are several theories about the origin of the Canary Islands ranging from the theory of hot spot specific for the Canary Islands described by Hoernle and Schmincke in 1993 to the theory of uplifted blocks described by Araña and Ortiz in 1991. However, the theory which is more accepted by Canaries Universities is a combination of both. This is because it can explain why the islands have a distribution west to east and why there is recent volcanic activity in islands where there shouldn’t be (Anguita and Hernán, 2000).

 

Another characteristic explained by Doniz (2005) is the distribution of three fracturing axes in the islands, one NE to SW, the other NW to SE and the last N to S. The position of these axes is very important because islands with more slope, landslides and volcanic activity are those in which the three fracturing axes are, such as in Tenerife, El Hierro (Cendrero, 1996) and, in lesser extent, La Palma. On the other hand, shield islands which only have one fracturing axis such as in Gran Canaria and La Gomera. Finally, in Fuerteventura and Lanzarote, where the erosion has played an important role, the relief of the islands is very soft with low slope although Lanzarote has suffered historic volcanic activity (Soler et al., 1990).

 

Today, submarine volcanic activity affects El Hierro with frequent earthquakes (Vervaeck, 2014) since 2011 with an important submarine eruption event in La Restiga located in the south of the island between October of 2011 and March 2012 (Carracedo et al., 2012).

 

The study area is mainly Tenerife and El Hierro and in general the occident islands because the most recent landslides are in these islands. Tenerife is the island with the highest altitude in the archipelago with 3,718 m (12,198 ft) in the volcanic structure that is in the middle of the island and form part of three landslides which we are studying. In Tenerife the contrast in the landscape of the north and the south caused by trade winds in the north part of the island are important and also, specific modifications in the climate because of small volcanos and landslides. Specific climate modifications have consequences in the local ecosystems creating high biodiversity in the islands (Machado, 2002). Moreover; comparison between El Hierro and Tenerife will be useful because both islands are in different steps in the volcanic structure.

 

In Tenerife six landslides affect the landscape according to Carracedo et al. (2009), Masson et al. (2002) and Seisdedos et al. (2012) although several authors recognize one landslide in the south of the island (Seisdedos et al., 2012 and Alonso et al., 2005). Ground truthing will shows if there are six or seven landslides in the island. In line with these authors, the island should have two landslides in the oldest part of the island where intensive erosive process affects and change the relief. Four with big slopes and cliffs could show clear boundaries of the landslides (fig. 5) and finally, the landslide in the south of the island which could not have a clear evidence of the landslide.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 5. Slope in the Landslide of La Orotava. Coordinates: 28º 30’ 87” N, -16º 54’ 05” W. Distance: 7 km across.

 

This study are proposed for this project is based on seven landslides called Anaga, Teno, Icod, La Orotava, Güímar, Roques de Garcia and Bandas del Sur (fig. 6).El Hierro has four landslides; El Golfo, El Julán, Las Playas I and Las Playas II (Seisdedos et al., 2012, Masson et al., 2002 and Carracedo et al., 2009) although Las Playas II is also known as San Andrés (Carracedo et al., 2009) (fig. 37).The study area has been selected based on the frequency and in the best preserved landslides. Both areas have similar characteristics and volcanic origins which permit a proper evaluation and comparison.