Hi John - These aren't stupid questions. We're not really sure how long it's been since Pavlof Sister erupted. On the basis of morphology, Pavlof Sister is labeled as "Late Pleistocene to Holocene", and there aren't any solid accounts of it erupting in historical times. Pavlof and Pavlof Sister are both part of the larger Emmons Lake Volcanic Center - their lavas have a common parent, although we believe that the eastern part (Pavlof, Pavlof Sister) has a closely-spaced, but separate magma chamber from the western part. (based on geochemistry, mostly). I'll send you a scientific paper in a separate email. Thank you, Cheryl -------- John Dickmon wrote: Stupid question but I'm going to ask it anyway.. A. How long has it been since Pavlof Sister erupted, and B. Are they the same magmatic system as say, Kilauea and Puʻu ʻŌʻō? -- Cheryl Cameron Geologist, Alaska Volcano Observatory Alaska Division of Geological & Geophysical Surveys voice: 907-451-5012 fax: 907-451-5050