In a series of three papers published in 1933, 1934, and 1941, Maurice Biot introduced the concept of response spectrum. The concept was then expanded and applied to various cases by George Housner. Ever since, the response spectrum concept has played a central role in earthquake engineering and engineering seismology. Biot in his 1941 BSSA paper expressed several original and visionary ideas and methods. The following is a selected list of items covered in his paper:
This classic paper was indeed very rich in pioneering concepts and methods; several of them are still valid and utilized after 62 years.