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Strong ground motion : N.S.F. Seminar-Workshop Proceedings

Helmberger, Donald V. and Jennings, Paul C. (1978) Strong ground motion : N.S.F. Seminar-Workshop Proceedings. California Institute of Technology .

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PREFACE The volume represents the Proceedings of a small Seminar - Workshop held at the Inn at Rancho Santa Fe, near San Diego, in February 1978. The meeting was conceived in response to a growing awareness of the mutual interest in research workers in seismology and earthquake engineers in the records of strong ground motion. The Seminar - Workshop was partly sponsored by the geophysical and earthquake engineering research programs within the National Science Foundation, and was jointly organized by Donald V. Helmberger of the Seismological Laboratory and Paul C. Jennings of the Earthquake Engineering Research Laboratory, of the California Institute of Technology. The organizers wish to take this opportunity to acknowledge the helpful assistance of Thomas Hanks, Leonard Johnson and S. C. Liu. INTRODUCTION The strong ground motion near the source of a major earthquake determines the forces which endanger buildings and other works of construction, and at. the same time is the most detailed clue available concerning the source mechanism of the earthquake. The records obtained of strong ground motion are, therefore, of interest to both seismologists and earthquake engineers, although the two disciplines have tended to look at the records quite differently, and to pursue their examinations separately. In the past few years, however, there has been a growing awareness of the mutual interest in strong ground motion and a number of individuals believed there would be considerable value in convening a small group of seismologists and earthquake engineers who are doing research on strong ground motion for a Seminar Workshop. It was envisioned that a Seminar - Workshop would be a useful means for scientists and engineers to discuss their mutual interests and problems, and to hear and discuss those areas where their interests and viewpoints are different. There are many fundamental questions in seismology and earthquake engineering which focus attention on the nature of strong ground motion. From the seismological viewpoint, the records of strong ground motion provide the best source of high frequency information on the way that energy is released during the rupture process. Additionally, strong motion data has the capability of providing a major means for determining the nature of the source mechanisms in great earthquakes. The extent of the source mechanism, the stress drop and other parameters of the source, and the range of complexity of source mechanisms are all capable of being studied through strong-motion records. From the engineering viewpoint the central problems are the characterization of strong ground motion for the purpose of establishing design criteria and the determination of the nature of the shaking in the near-field of major and great earthquakes. These problems are faced in the design of almost every major facility in the more seismic areas of the country and there is not yet a consensus or how to deal with them. To resolve these important practical problems requires a much increased understanding of strong ground motion. A problem of mutual interest to both seismologists and earthquake engineers is the way the earthquake motion is altered as it propagates away from the source. Seismologists have examined this problem by studies of radiation patterns under idealized conditions and by calculating the effects of regional geology on ground motions of periods of one second and more. Under similar assumptions, earthquake engineers have calculated the effects of surficial soil deposits on strong ground motions of shorter period. At a few institutions significant interaction between seismologists and earthquake engineers has developed, but there is clearly a benefit to be gained. by much more communication between the two disciplines; it was the intent of the Seminar - Workshop to accelerate this communication. It was also hoped that a number of areas of mutual interest and research need could be identified. This report, which contains extended abstracts of the invited papers, represents the Proceedings and the Seminar - Workshop. The papers and the discussions at the conference were grouped around three major areas. (1) Characterization and parameterization of strong ground motions. (2) Simulation and modeling of strong motions: deterministic and statistical. (3) Source mechanisms and estimation of strong motion for great earthquakes. The invited papers are followed by a brief discussion of the directions of future research. D. V. Helmberger P. C. Jennings

Item Type:Report or Paper (Technical Report)
Group:Earthquake Engineering Research Laboratory
Record Number:CaltechEERL:EERL.1978.002
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ID Code:26536
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Deposited On:11 Mar 2003
Last Modified:26 Dec 2012 13:59

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