The tectonic and geological background

A context for the geological setting of the Azores with emphasis on the volcanism and seismicity associated with the nine populated islands is presented. In terms of regional tectonics, the Azores archipelago occurs at the triple point junction of the North American, Nubian and Eurasian tectonic plates. The formation of the Azores is considered to be associated with a volatile-rich ‘hot spot,’ probably caused by some form of mantle plume from heterogeneous sources. For those with a geological background, a brief introduction is provided on the genesis of magmas that feed the Azores volcanoes. The geological framework, volcanic history and seismicity of all nine islands are briefly described. A table provides a glossary explaining the technical terms used in the text to describe volcanic eruptions and their products. Consideration of each of the islands gives an overview of the styles of volcanic activity and the distribution of damaging earthquakes.