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|Title:||State-of-the-art for assessing earthquake hazards in the United States. Report 6, Faults and earthquake magnitude|
|Authors:||Mackay School of Mines.|
Slemmons, David B.
Earthquake resistant structures
|Publisher:||Soils and Pavements Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
Abstract: The short seismologic and historic records, in combination with the long recurrence intervals between potentially damaging earthquakes, create a need for developing geologic methods as alternatives or supplements to seismologic methods of establishing design earthquakes. The main goal of this report is to review geologic methods of determining the maximum probable earthquakes for active faults based on empirical relationships between magnitude, length of surface faulting, maximum fault displacement, and combinations of fault length and maximum displacement. Empirical studies have developed and refined the formulations and graphs relating earthquake magnitude to surface faulting. The present study updates the most recent studies of this type on the basis of data that have become available over the past six years. The application of the method requires the careful determination of fault activity or nonactivity, or rate of activity, and an integrated program of historic, seismologic, geologic, geomorphic, and geophysical studies. The criteria for activity are summarized and methods of resolving questions of activity are provided. The geomorphic evidence for activity and type of fault is summarized in terms of complex, branching, conjugate, and distributed fracture patterns that require a regional and integrated geological and geophysical approach. The relationship of fracture patterns is presented in terms of plate tectonic environments and conjugate deformation by faulting, folding, and warping. The complex pattern analysis required for distributed fracture systems is considered for each fault type -- strike-slip, normal-slip, reverse-slip, and oblique-slip -- with examples and source literature provided for each type. Case histories are given for the selection of design values. NOTE: This file is large. Allow your browser several minutes to download the file.
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