OPERATIONAL MAGNIFICATION AND PHYSICAL ENVIRONMENT OF SEISMOGRAPH STATIONS

Abstract

Maximum satisfactory operational magnifications of 115 standardized seismograph stations in the United States range from 30,000 to 630,000 and are used to evaluate the sites relative to one another. Grouping the sites according to physiographic province, rock type, distance from cultural features, and type of installation shows distinct correlation between physical environment and operating magnification. As composites of the sites studied, the highest magnification site is a mine in an igneous intrusive body in the Basin‐Range province; the lowest magnification site is a surface installation on poorly consolidated sedimentary rock on the Coastal Plain. Regional variations of magnification capability are closely related to physiographic provinces; local variation within a province is as great as the variation of physical environment.