Volcanology: warning signs and decisions

A volcano that will never erupt again is erloschen, and the word shows a rule of German grammar more clearly than most. It is the past participle of erlöschen, to go out, a strong verb that forms its perfect with sein: das Feuer erlischt, es erlosch, es ist erloschen. Set the past participle of such a sein verb in front of a noun and it says what the noun has done or undergone by itself: der erloschene Vulkan is the volcano that has gone out. The past participle of a verb that takes an object works the other way round and says what somebody did to the noun: der gelöschte Brand is the fire that was put out. The same pattern gives die erkaltete Lava, lava that has cooled of its own accord, and it is why a volcanologist never calls a mountain gelöscht: nobody put it out.