Quantitative classification of pulse-like ground motions

Graduate researcher: Shrey Shahi

Project sponsor: National Science Foundation

Additional details and software regarding this project are provided here.


Figure from Baker, 2007

Ground motions with velocity pulses caused by near-fault directivity have received a great deal of attention from engineers and seismologists because of their potential to cause severe damage to structures. Many studies have investigated the dynamic response of structures to these "pulse-like" ground motions, but the ground motions are typically identified using judgment rather than some classification procedure. The lack of a systematic, quantitative classification scheme has hindered progress in answering even seemingly simple questions such as the probability that a ground motion with a given magnitude, distance and source-site geometry will have a velocity pulse. In this project, a quantitative scheme for detecting pulses is being developed. The procedure uses a wavelet-based signal decomposition to identify and extract the largest velocity pulse from a ground motion, and if the extracted signal is large relative to the remaining signal, the ground motion is classified as a pulse-like motion. The identified pulse-like ground motions are then being used in dynamic nonlinear structural analyses to identify relationships between near-fault directivity effects and structural response.


Selected publications:

Spudich, P., Watson-Lamprey, J., Somerville, P. G., Bayless, J., Shahi, S. K., Baker, J. W., Rowshandel, B., and Chiou, B. S. J. (2012). “Directivity models produced for the Next Generation Attenuation West 2 (NGA-West 2) project.” Proceedings of 15th World Conference on Earthquake Engineering, Lisbon, Portugal, 9p.
Shahi, S., and Baker, J. W. (2011). “An empirically calibrated framework for including the effects of near-fault directivity in probabilistic seismic hazard analysis.” Bulletin of the Seismological Society of America, 101(2), 742-755.
Shahi, S. K., and Baker, J. W. (2011). “Regression models for predicting the probability of near-fault earthquake ground motion pulses, and their period.” 11th International Conference on Applications of Statistics and Probability in Civil Engineering, Zurich, Switzerland, 8p.
Shahi, S. K., and Baker, J. W. (2010). “Signal Processing and Probabilistic Seismic Hazard Analysis Tools for Characterizing the Impact of Near-Fault Directivity.” Proceedings, 7th International Conference on Urban Earthquake Engineering (7CUEE) & 5th International Conference on Earthquake Engineering (5ICEE), Tokyo, Japan, 6p.
Green R.A., Lee J., White T.M., and Baker J.W., (2008) The significance of near-fault effects on liquefaction, 14th World Conference on Earthquake Engineering. Beijing, China. 8p.
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.
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.
Tothong P., Cornell C.A., and Baker J.W. (2007). Explicit directivity-pulse inclusion in probabilistic seismic hazard analysis, Earthquake Spectra, 23 (4), 867-891.