In fact, a full frequency of vibrations occurs. I usually point out that most loss of life and property has been due to the collapse of antiquated and unsafe structures, mostly of brick and other masonry. At least there is progress of California toward building new construction according to earthquake-resistant design. We would have less reason to ask for earthquake prediction if this was universal. I realize your views on prediction.
Nothing is less predictable than the development of an active scientific field.
In seismology, we have an increasing number of people and resources at work, so that it's entirely imaginable that there will be a breakthrough in some quite unforeseen area. Abridged from the Earthquake Information Bulletin . 12, No. 1, January - February, 1980.