Skip Links

USGS - science for a changing world

U.S. Geological Survey Open-File Report 78–287

FORTRAN Programs for Calculating Nonlinear Seismic Ground Response in Two Dimensions

By William B. Joyner

Thumbnail of and link to report PDF (43.7 MB)Introduction

The programs described here were designed for calculating the nonlinear seismic response of a two-dimensional configuration of soil underlain by a semi-infinite elastic medium representing bedrock. There are two programs. One is for plane strain motions, that is, motions in the plane perpendicular to the long axis of the structure, and the other is for antiplane strain motions, that is motions parallel to the axis. The seismic input is provided by specifying what the motion of the rock-soil boundary would be if the soil were absent and the boundary were a free surface. This may be done by supplying a magnetic tape containing the values of particle velocity for every boundary point at every instant of time. Alternatively, a punch card deck may be supplied giving acceleration values at every instant of time. In the plane strain program it is assumed that the acceleration values apply simultaneously to every point on the boundary; in the antiplane strain program it is assumed that the acceleration values characterize a plane shear wave propagating upward in the underlying elastic medium at a specified angle with the vertical.

The nonlinear hysteretic behavior of the soil is represented by a three-dimensional rheological model. A boundary condition is used which takes account of finite rigidity in the elastic substratum. The computations are performed by an explicit finite-difference scheme that proceeds step by step in space and time. Computations are done in terms of stress departures from an unspecified initial state.

Source listings are provided here along with instructions for preparing the input. A more detailed discussion of the method is presented elsewhere.

  • This report is available only on the Web.

For additional information:
Contact Information, Earthquake Science Center, Menlo Park Science Center
U.S. Geological Survey
345 Middlefield Road, MS 977
Menlo Park, California 94025

This report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.

Suggested citation:

Joyner, W.B., 1978, FORTRAN programs for calculating nonlinear seismic ground response in two dimensions: U.S. Geological Survey Open-File Report 78–287, 72 p., available at



The Plane Strain Program

The Antiplane Strain Program

Adaptation to Computer Systems Other Than CDC


Planestrain Program Source Listing and Output Listing for Sample Problem

Plane Strain Program Listing of Input Deck for Sample Problem

Anti Plane Strain Program Source Listing And Output Listing For Sample Problem

Anti Plane Strain Program Listing of Input Deck for Sample Problem

Accessibility FOIA Privacy Policies and Notices logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: Contact USGS
Page Last Modified: Wednesday, November 23, 2011, 02:42:46 PM