There has been an increasing awareness of seismic hazards over the years, in part due to the increasing complexity of modern society and the recent occurrence of several destructive earthquakes. About 20% of the papers presented at the Sixth World Conference on Earthquake Engineering, which was held in New Delhi, India, from January 10 to 14, 1977, dealt with seismicity, ground motion, recent destructive earthquakes, instrumentation, and seismic zoning.
The principal focus of these deliberations was the study of ground motion due to an earthquake. The design and construction of major engineering facilities sucjh as dams, pipelines, stnd nuclear power plants require a specification of ground motion. Consequently, seismologists are called upon to predict ground motion at a particular site of interest. Prediction for engineering purposes implies prediction of amplitude, frequency content, and duration of ground motion. Consequently, in the last few years, various parameters which can affect the severity of ground motion have been studied. The severity of ground motion at a place will be clearly influenced by the nature and degree of seismic activity in the area, transmission path, and local geology. Thus the central theme of this conference was to identify parameters which affect ground motion and, if possible, establish mathematical and statistical models for its prediction.