Research areas: Pulse classification

 
    Research Topics: General | Epsilon | Pulse Classification | Attenuation scripts |

Quantitative Classification of Near-Fault Ground Motions Using Wavelet Analysis

by Jack Baker, January 2007

This web page provides documentation and supporting software for the manuscripts:

Baker J.W., 2007. Quantitative classification of near-fault ground motions using wavelet analysis. Bulletin of the Seismological Society of America. 97 (5), 1486-1501.

Baker J.W., 2008. Identification of near-fault velocity pulses and prediction of resulting response spectra, in Geotechnical Earthquake Engineering and Soil Dynamics IV, Sacramento, California, 10 pp.

The manuscript describes an approach for analyzing earthquake ground motions using wavelet analysis, to quantitatively identify strong velocity pulses that might be caused by directivity effects. While the paper describes the method, the author believes that complete documentation of the project should include the software used to perform the analysis, documentation of that software, and summary results from the analyses. This website serves to provide that documentation, allowing others to reproduce the results published in the manuscript.

Disclaimer: You are welcome to download and use any of these materials, as long as you acknowledge this website and paper as the source of the data. The Matlab scripts are free software; you can redistribute them and/or modify them under the terms of the GNU General Public License as published by the Free Software Foundation, version 2. This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

Available Downloads

Plots of pulse-like ground motions. This .pdf plots of the 91 fault-normal pulse-like ground motions from the NGA database, along with their associated relevant metadata. Plots of the original velocity time history and extracted pulse are given, along with metadata from the NGA "flatfile" that may be useful for determining whether the observed pulse was caused by directivity effects.

Acceleration time histories of pulse-like ground motions and extracted pulses. These text files contain acceleration time histories for the 91 fault-normal pulse-like ground motions. The original record, extracted pulse, and residual record are labeled accordingly. Record numbers correspond to those used in the paper and elsewhere on this website. The first line of each file contains the time step and number of points in the ground motion, and the remaining rows contain the accelerations over time in units of g.

Matlab Scripts. This .zip file contains the basic functions used in the ground motion classification procedure. The script "main_analyze_ground_motion.m" calls the other functions provided in the .zip file, and demonstrates how they are used to analyze an example ground motion. Note, however, that this current version of the scripts requires the Matlab Wavelet toolbox.

Classification results for the NGA database. This Excel spreadsheet contains results from classifications of all ground motions in the NGA database (after they were rotated to fault-normal and fault-parallel orientations). Results are provided separately for the following criteria:

  • "Pulse Indicator" score
  • Whether the pulse is late arriving
  • Whether the peak ground velocity is greater than 30 cm/s
  • Classification of the pulse, based on the previous three results
  • Pulse period

Using these basic results, a user can easily determine how the set of identified pulse-like ground motions changes as the classification procedure is modified. The results are provided in the same format as the NGA flatfile (http://peer.berkeley.edu/nga), so they can be easily appended into that larger flatfile for use in ground motion studies.

Summary results for pulse-like ground motions. This Excel spreadsheet provides the data from Figure 1 of the manuscript in electronic form, and adds a few additional fields to the table.

Plots of pseudo-velocity spectra from pulse-like ground motions. This .zip file contains plots of pseudo-velocity spectra for the 91 pulse-like ground motions identified in the companion paper, along with spectra from their extracted pulses and residual ground motions. These figures can be used to compare wavelet-based pulse periods to periods associated with peak pseudo velocity. The figures are provided in .emf format, and the title on each figure indicates the associated record number and the wavelet-based pulse period. The number given in the filename refers to the record number in Table 1 of the manuscript.