Hello everyone. I am trying to research seismometers for a project. I need to know the physics of the seismometer. Preferably the older, mechanical ones, not the modern electronic ones I won't understand. I need to bring in ideas of resonance, forced oscillations etc. I have tried googling this topic, but I have not found anything on the physics. Sure, many sites, including Wikipedia, give a lot of backround material, and explain the general idea of a seismometer, but I have not found a website that gives a type of seismometer and explains the physics. I tried looking for a book in the university library but found nothing. Similarly with online journals. Any help at all in finding sources would be ery much appreciated. Thanks.