I was very impressed by how fast you guys answered me. The information will keep me busy for quite a while. The harmonic tremor jpg was great - looked like an ekg of someone in V-fib! Don, yes I was interested in volcanic seismicity - I check out Long Valley often. Was also wondering about the USGS map I found on the site below. Besides Long Valley, I've noticed that the other potential volcanic sites are very siesmically active. Is it possible to tell if any of these earthquakes are due to magna movement instead of plate tectonics? Excuse all the questions but when I check out the USGS recent California earthquakes and see so many of them are shallow and in the potential volcanic areas, it makes me wonder. You guys are great - I'll try not to take up too much of your time.

• Volcanoes-California Hazards Map