Design ground motions near active faults

  • Jonathan D. Bray University of California, Berkeley, USA
  • Adrian Rodriguez-Marek Washington State University, Pullman, USA
  • Joanne L. Gillie HWA Geosciences, Lynnwood, USA


Forward-Directivity (FD) in the near-fault region can produce intense, pulse-type motions that differ significantly from ordinary ground motions that occur further from the ruptured fault. Near-fault FD motions typically govern the design of structures built close to active faults so the selection of design ground motions is critical for achieving effective performance without costly over-design. Updated empirical relationships are provided for estimating the peak ground velocity (PGV) and period of the velocity pulse (Tv) of near-fault FD motions. PGV varies significantly with magnitude, distance, and site effects. Tv is a function of magnitude and site conditions with most of the energy being concentrated within a narrow-period band centred on the pulse period. Lower magnitude events, which produce lower pulse periods, might produce more damaging ground motions for the stiff structures more common in urban areas. As the number of near-fault recordings is still limited, fully nonlinear bi-directional shaking simulations are employed to gain additional insight. It is shown that site effects generally cause Tv to increase. Although the amplification of PGV at soil sites depends on site properties, amplification is generally observed even for very intense rock motions. At soft soil sites, seismic site response can be limited by the yield strength of the soil, but then seismic instability may be a concern.


Somerville, P.G., Smith, N.F., Graves, R.W., and Abrahamson, N.A. (1997) “Modification of empirical strong ground motion attenuation relations to include the amplitude and duration effects of rupture directivity”. Seismological Research Letters, 68(1), 199-222. DOI:

Stewart, J.P., Chiou, S-J, Bray, J.D., Graves, R.W., Somerville, P.G., Abrahamson, N.A. (2001) “Ground Motion Evaluation Procedures For Performance-Based Design, PEER-2001/09”. Pacific EQ Engrg. Research Center, Univ. of Calif., Berkeley, Sep., 229 pages.

Abrahamson, N.A. (2000) “Effects of rupture directivity on probabilistic seismic hazard analysis”. Proceedings, Sixth International Conference on Seismic Zonation, Palm Springs, CA, Nov. 12-15.

Alavi, B., and Krawinkler, H. (2000) “Consideration of near-fault ground motion effects in seismic design”. Proceedings, 12th World Conf. on Earthquake Engineering., Auckland, New Zealand.

Sasani, M. and Bertero, V.V. (2000) “Importance of severe pulse-type ground motions in performance-based engineering: historical and critical review”. Proc., 12th World Conf. on EQ Engrg., Auckland, New Zealand.

Somerville, P.G. (1998) “Development of an improved ground motion representation for near-fault ground motions.” SMIP 98, Seminar on Utilization of Strong Motion Data: Oakland, CA.

Mavroeidis, G.P., and Papageorgiou A.S. (2003) “A mathematical representation of near-fault ground motions.” Bulletin of the Seismological Society of America, 93(3), 1999-1131. DOI:

Bray, J.D., and Rodriguez-Marek, A., (2004) “Charac-terization of forward-directivity ground motions in the near-fault region.” Soil Dynamics and Earthquake Engineering, 24, 815-828. DOI:

Gillie J.L. (2005) Nonlinear Response Spectra of Forward-Directivity Ground Motions. MSc Thesis, Washington State University, Pullman, WA.

Abrahamson, N.A., and Youngs, R.R. (1992) “A stable algorithm for regression analyses using the random effects model”. Bulletin of the. Seismological Society of America, 82(1), 505-510.

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. DOI:

International Code Council (2006) International Building Code, Country Club Hills, IL.

Rodriguez-Marek, A. and Bray, J.D. (2006) “Seismic site effects for near-fault forward directivity ground motions”, Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 132(12), 1611-1620. DOI:

Borja, R.I., and Amies, A.P. (1994) “Multiaxial cyclic plasticity model for clays”. Journal of Geotechnical Engineering, ASCE, 120(6), 1051-1070. DOI:

Lysmer J.M., and Kuhlmeyer, A.M. (1969) “Finite dynamic model for infinite media”. Journal of the Engineering Mechanics Division, ASCE, 95(4) 859-877.

Espinoza R.D., Bray, J.D., Soga, K., and Taylor, R.L. (1995) GeoFEAP: Geotechnical Finite Element Analysis Program, Report UCB/GT/95-05, Dept. Civil Eng., Univ. of California, Berkeley.

Rodriguez-Marek, A. (2000) Near-Fault Seismic Site Response. Ph. D. Dissertation. Univ. of Calif., Berkeley.

Hardin, B. O., and Drnevich, V. P. (1972) “Shear modulus and damping in soils: measurements and parameter effects”. Journal of the Soil Mechanics and Foundation. Engineering, ASCE, 98(SM6), 603-624.

Lefebvre, G., and LeBoeuf, D., (1987) “Rate effects and cyclic loading of sensitive clays.” Journal of. Geotechnical Engineering, ASCE, 113(5), 476-489. DOI:

Vucetic, M., and Dobry, R. (1991) “Effect of Soil Plasticity on Cyclic Response”. Journal of. Geotechnical Engineering, ASCE, 117(1), 89-107. DOI:

Isenhower, W. M., and Stokoe, K. H. II, (1981) “Strain-rate dependent shear modulus of San Francisco Bay mud”. Inter. Conf. on Recent Advances in Geotechnical EQ Engineering., Univ. of Missouri, Rolla, 597-602.

How to Cite
Bray, J. D., Rodriguez-Marek, A., & Gillie, J. L. (2009). Design ground motions near active faults. Bulletin of the New Zealand Society for Earthquake Engineering, 42(1), 1-8.

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