Hello Geoff - I've cc'd Kristi Wallace on this reply, who is better able to answer your questions than I am. Thanks! Cheryl Cameron -------- Geoff Van Horn wrote: Greetings! My name is Geoff and I am currently a Geological Sciences major at UAA. In my free time I do experiments with gamma spectroscopy and X-ray fluorescence. Last weekend I took advantage of our little rain storm and filtered ten gallons of rain as it fell. My hope was to collect a gamma ray spectrum of beryllium-7, and maybe some radon-222 daughters. Instead, my spectrum was dominated by lead-212, a short lived daughter of radon-220, and thorium-232. The daughters of thorium-232 from radon and below have extremely short half lives which had me wondering if thorium and its daughters were being injected into the atmosphere by volcanic activity. Is there any data on the composition of Bogoslof ash? Or better yet, would it be possible to obtain a small sample of ash, say a cubic inch? I'd be interested to correlate the lead-212 from last weekends rain to a possible cause. Assuming we get the forecast thunderstorms tonight, I will be filtering another batch of rain for spectroscopy. Thank you for your time Geoff -- Cheryl Cameron Geologist, Alaska Volcano Observatory Alaska Division of Geological & Geophysical Surveys voice: 907-451-5012 fax: 907-451-5050