Complex sentence: The official name of the mountain is Redoubt Volcano, a translation of the Russian name "Sopka Redutskaya", referring to, as does the word "redoubt", "a fortified place".
Split into simpler sentences: The official name of the mountain is Redoubt Volcano. The name is a translation of the Russian name "Sopka Redutskaya", referring, as does the word "redoubt", to "a fortified place".