Location

St. Louis, Missouri

Session Start Date

4-26-1981

Session End Date

5-3-1981

Abstract

Soon after the main shock of Friuli, Italy, May 6th 1976 earthquake, two strong motion recorders accelerographs were installed in two sites about 650 meters distant one from the other. One instrument was installed on hard outcropping rock, the other at the surface of an alluvial deposit 20+25 meters thick underlain by a sloping bedrock. Among the numerous records obtained three aftershocks of magnitude about 6 and hypocentral distance within 20 Km, are investigated by comparing maximum accelerations, durations, Arias intensity and Husid ratios. A new numerical tool is proposed which consists of a series of plots of the Husid ratios of low-pass filtered accelerograms. The numerical tool seems to be very promising since it allows to describe at the same time energy, duration and frequencies content, of a given ground motion. Moreover the application to the records simultaneously obtained at the two stations suggests that it would be more appropriate to define an accelerogram according to the type of "behavior" shown by the site during a certain earthquake rather than according to the local site characteristics like soft or hard.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

First Conference

Publisher

University of Missouri--Rolla

Publication Date

4-26-1981

Document Version

Final Version

Rights

© 1981 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 26th, 12:00 AM May 3rd, 12:00 AM

Local Site Behaviour in the 1976 Friuli Earthquake

St. Louis, Missouri

Soon after the main shock of Friuli, Italy, May 6th 1976 earthquake, two strong motion recorders accelerographs were installed in two sites about 650 meters distant one from the other. One instrument was installed on hard outcropping rock, the other at the surface of an alluvial deposit 20+25 meters thick underlain by a sloping bedrock. Among the numerous records obtained three aftershocks of magnitude about 6 and hypocentral distance within 20 Km, are investigated by comparing maximum accelerations, durations, Arias intensity and Husid ratios. A new numerical tool is proposed which consists of a series of plots of the Husid ratios of low-pass filtered accelerograms. The numerical tool seems to be very promising since it allows to describe at the same time energy, duration and frequencies content, of a given ground motion. Moreover the application to the records simultaneously obtained at the two stations suggests that it would be more appropriate to define an accelerogram according to the type of "behavior" shown by the site during a certain earthquake rather than according to the local site characteristics like soft or hard.