Ground Motion Sets

Full Far-Field Ground Motion Set

 

In my research and related work, we developed a general far-field ground motion set for use in structural analyses and performance assessment. This ground motion set includes 39 pairs of horizontal ground motions (so 78 components total). 

This set also includes the 22 pair of motions that comprise the FEMA P695 (ATC-63) far-field ground motion set, which was created in parallel with this research (the 22 motions are indicated in the table below). The FEMA P695 (ATC-63) has more extensive documentation that is available below (later on this page) and from ATC at www.atcouncil.org.

We selected this ground motion Set One (called "Basic Far-Field Set" or "Set FFext") to consist of strong motions that may cause structural collapse of modern buildings. This typically occurs at extremely large levels of ground motion, so this ground motion set was selected to represent these extreme motions to the extent possible. To ensure that the records represent strong motion that may cause structural collapse, we imposed minimum limits on event magnitude, as well as peak ground velocity and acceleration. The limits were chosen to balance selection of large motions, while ensuring that enough motions will meet the selection criteria.

a) Magnitude > 6.5
b) Distance from source to site > 10 km (average of Joyner-Boore and Campbell distances)
c) Peak ground acceleration > 0.2g AND peak ground velocity > 15 cm/sec
d) Soil shear wave velocity, in upper 30m of soil, greater than 180 m/s (NEHRP soil types A-D; note that all selected records happened to be on C/D sites)
e) Limit of six records from a single seismic event; if more than six records pass the initial criteria, then the six records with largest PGV are selected, but in some cases a lower PGV record is used if the PGA is much larger.
f) Lowest useable frequency < 0.25 Hz, to ensure that the low frequency content was not removed by the ground motion filtering process
g) Strike-slip and thrust faults (consistent with California)
h) No consideration of spectral shape (e)
i) No consideration of station housing, but PEER-NGA records were selected to be "free-field"

The table shown below that documents this ground motion set can be found here.

database table 1


The set of ground motions are available here, including the acceleration time history files, as well as files of the time step and the number of points in the ground motion records.

FEMA P695 (ATC-63) Far-Field Ground Motion Set

The FEMA P695 (ATC-63) Far-Field Ground Motion Set is described in Appendix A of the FEMA P695 report and is provided in the following set of files:

Summary file including record information and documentation [link].

Ground motion acceleration time histories are provided in three formats:

  •  Excel file [link]
  •  Original PEER-NGA text files [link]
  •  Sorted text files [link]
Ground motion acceleration spectra are provided in two formats: