Wired published an article on volcanic eruptions this week, including one in Cape Verde Islands http://www.wired.com/2016/08/volcanic-eruptions-indonesia-interfering-flights/ It seems Brava has been considered a dormant stratovolcano. http://volcano.si.edu/volcano.cfm?vn=384020 The article mentions phonolite eruptions, which I take to mean phonolite deposits from previous eruptions. Phonolite has a high silica content that can produce explosive eruptions. As I recall, the Cascade volcanoes, like Mt. St. Helens have high silica content, which makes for explosive eruptions. Fogo - http://volcano.si.edu/volcano.cfm?vn=384010 Fogo had activity in February 2015. Basanites are most commonly associated with continental rift and ocean island magmatism. They are sometimes parental magmas to a crystal fractionation series that leads to phonolites. https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?Term=basanite https://wwwf.imperial.ac.uk/earthsc...ocklibrary/viewglossrecord.php?Term=phonolite Apparently, the Canary Islands also have basinitic/phonolitic deposits.