Does anyone know of a site that explains harmonic tremors in depth? I would like to see an illustration of what they look like on a seismogram. By the way, this is my first post, but I've been interested in earthquakes and volcanos ever since I saw photos of volcanos taken by the late Maurice and Katia Krafft. I have been reading posts on this site for months and have found it to be very helpful in my learning process. I'm not from Calif, but do live near earthquake country (New Madrid). Please bear with my lack of knowledge! Thanks in advance for any help.