Use this program to modify response spectra generated by attenuation relationships or empirical methods. Modifications available are: converting from Sa to Sv or Sd, changing the damping ratio [R1], scaling with respect to PGA, converting to fault normal or fault parallel Sa spectra [R2], and converting spectra from linear to nonlinear using strength reduction factors.
You may choose more than one modification at once, but some modifications will not work if certain previous modifications have been performed (ie. adding directivity, only defined for Sa, after converting a spectrum to Sv or Sd). Additional information regarding the methods used in this program can be found in the course notes. Please be aware that large modifications cause the spectrum to lose its physical meaning.

Modspec	Interactive Spectrum Modification
Spectrum to use
	Current existing	Type: Sa Sv Sd
		Model: Newmark & Hall Abrahamson & Silva Boore, Joyner, Fumal Campbell Sadigh et al. SEA96 Toro et al. Atkinson & Boore (E) Atkinson & Boore (C) Youngs, et al. None available
	Generate empirical spectrum
	Generate from attenuation relationship

Current spectrum		Model: Newmark & Hall Abrahamson & Silva Boore, Joyner, Fumal Campbell Sadigh et al. SEA96 Toro et al. Atkinson & Boore (E) Atkinson & Boore (C) Youngs, et al. None available    Type: Sa Sv Sd
Linear Options
Convert:		from Sa Sv Sd to Sa Sv Sd
Change damping		from 1% 2% 3% 5% 7% 10% 20% to   1% 2% 3% 5% 7% 10% 20%
		using Newmark - Hall FEMA 273
Scale to PGA		New PGA (g)
Add directivity		Convert component to Fault Normal Fault Parallel
Convert to nonlinear
Use model: Newmark and Hall Miranda for rock sites Miranda for alluvium sites Miranda for soft soil sites Riddell, Hidalgo and Cruz Nassar and Krawinkler			Ductility m: 2 3 4 5 6 8

Numerical Values:


Copyright 1999 Janise Rodgers, Pacific Earthquake Engineering Research Center, University of California, Berkeley.