Earthquake Hazards Program

U.S. Geological Survey
Open-File Report 2006-1369
Version 1.0

C-Language Software for Computing Strong Ground Motion Metrics and Seismograph Self Noise

By J.R. Evans, R.L. Nigbor, and C.R. Hutt


This Open-File Report releases several software modules for public use. No warrantees, implied or explicit, are given for this software.

The software modules are (1) C‑language integer code for approximate, rapid computation of peak ground velocity (PGV) starting from an integer accelerogram (digitizer counts) and using integer arithmetic with no multiply or divide operations, (2) C‑language double-precision code (and an example of integer code for part of this computation) for computing the response spectral acceleration and related ground-motion metrics (Sa, Sv, Sd, PSV) of an accelerogram (provided in units of cm/s2) by the method of Nigam and Jennings (1969), and (3) a MatLab (Version 7.1) “.m” script for computing instrument self-noise from a long recording of the self noise of (a) a recorder with shorted inputs or, (b) a complete seismographic system at a location with ambient seismic ground seismic noise well below instrument self noise. The latter, if the self noise of the recorder is lower or is subtracted, represents the self noise of the seismic sensor.

Test examples are provided for each routine so that users can verify their implementations of this software.

Download this report as a six-page PDF file (of2006-1369.pdf; 192 KB)

Download Peak Ground Velocity via Integer Computation (13.8 MB)

Download Response Spectral Acceleration Computation (952 KB)

Download Self-noise Computation via MatLabTM (4.5 MB)

For questions about the content of this report, contact John R. Evans

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