EZ-FRISK™ contains a large number of programmed attenuation equations along with their coefficients. EZ-FRISK™ allows you to edit the coefficients as desired. Therefore, you can also define other equations that have the same equation form as those already programmed.

Since one of the equation forms is an interpolation table, you can specify arbitrary attenuation relationships. You provide a table of discrete values of magnitude, distance, acceleration and sigma for the program to interpolate for various spectral periods. For some attenuation relationships, such as Atkinson-Boore (1995), authors recommend using the tabular form rather than the equation form.

The following equations are available in EZ-FRISK™:

• Abrahamson-Silva (1997)
• Al-Tarazi and Qadan (1997)
• Ambraseyes (1996)
• Amrat (1996)
• Atkinson (1997)
• Atkinson-Boore (1995-2003)
• Atkinson-Motazedian (2002)
• Atkinson-Silva (2000)
• Atkinson-Sonley (2000)
• Boore-Atkinson (2006) NGA
• Boore-Joyner-Fumal (1993, 1994, 1997)
• Campbell (1993, 1997, 2003)
• Campbell-Bozorgnia (1994, 2003, 2006)
• Chiou-Youngs (2006) NGA
• Crouse (1991)
• Frankel (1997)
• Fukushima-Tanaka (1992)
• Gregor (2002)
• Huo-Hu (2002)
• Idriss (1993)
• Malkawi-Fahmi (1996)
• Subetta-Pugliese (1996)
• Sadigh (1993, 1994, 1997)
• Silva (2002)
• Sommerville (2001)
• Spudich (1997, 1999)
• Toro (1997, 1999)
• Youngs (1988, 1997)

The attenuation equation database can be used with any number of seismic hazard analyses. You can select one or more attenuation equations to use with each seismic source. You can also assign different equations to different sources. For example, you can assign different attenuation equations to subduction zones then those used for your fault or background seismic sources. You can easily recalculate results if the attenuation equation database is updated.