引言感谢地震工程研究会的热情邀请,使我有机会出席为纪念研究会成立50周年而举行的讲演会。 1963年我离开澳大利亚时,那里的地震学家们正在对穿过地核的微弱地震波进行研究。地球的中心那时被认为是数学家们的天地,因而对澳大利亚地震学家来说,合适的课题只是一些主要的灾害,像蛇、森林火灾等,而不是地震灾害。我也是在成为加州大学伯克利分校的地震学教授之后才对此有些认识的。那时人们特别是工 INTRODUCTION Thank you to the Earthquake Engineering Research Association for your warm invitation to give me the opportunity to attend a lecture to mark the fiftieth anniversary of the Institute. When I left Australia in 1963, seismologists there were studying the weak seismic waves that passed through the core. Earth’s center was then considered the world of mathematicians, so for Australian seismologists, the appropriate subjects were just some of the major disasters, such as snakes and forest fires, rather than earthquake disasters. I did not know anything about it until I became a professor of seismology at the University of California, Berkeley. At that time, people were especially workers