Electronic Supplement to
Regional Correlations of VS30 and Velocities Averaged Over Depths Less Than and Greater Than 30 m

by David M. Boore, Eric M. Thompson, and Héloïse Cadet

Estimates of VS30 at K-NET stations

Table S1. A csv file with VS30 values for K-NET stations, estimated from the equations relating VS30 to VSZ in Table 2 of the text, derived from KiK-net models, and in Table 2 of Boore (2004), derived from California velocity models. In these estimations z is the depth to the bottom of the velocity model at each site (zmax). The file includes the following columns, with the units indicated at the end of each description:

  1. station name (sta)
  2. depth to the bottom of the model (zmax), m.
  3. velocity of the layer at the bottom of the model (vmax), m/s.
  4. travel time from the surface to zmax, s.
  5. time-averaged velocity from the surface to the bottom of the model (vavg), s.
  6. VS30 estimated by assuming that vmax continues to 30 m (the "constant-velocity" extrapolation), m/s.
  7. VS30 estimated from the KiK-net equations, m/s.
  8. VS30 estimated from the California equations, m/s.
  9. VS30 estimated as a weighted combination of the estimates from the KiK-net and the California equations, where the weighting equals unity for the KiK-net estimates if zmax is less than or equal to 10 m, unity for the California estimates if zmax is greater than or equal to 20 m, with linear weighting between these two values for zmax between 10 m and 20 m. The motivation for this justification is given in the text of the article, m/s.
  10. ratio of VS30 from the combined estimate and the constant-velocity extrapolation
  11. ratio of VS30 from KiK-net equations and the California equations

Table S2. A csv file containing names of those K-NET stations without valid velocity models.

Figure S1. Histograms of the various estimates of VS30 at K-NET stations; also shown are the lines corresponding to 10, 50, and 90 percentiles of the combined estimates. The mean of the log values of the combined estimates is the equivalent of 337 m/s (log values are shown in the graph because the VS30 values have a log-normal distribution, as shown in the article).

Figure S2. The histograms of the ratios of the various estimates of VS30. "KiK", "Cal", "Combined", and "Xtrap" are estimates from the KiK-net equations, the California equations, the weighted combination of those estimates (see above) and the constant-velocity extrapolation, respectively.


Boore, D. M. (2004). Estimating VS(30) (or NEHRP Site Classes) from shallow velocity models (depths < 30 m), Bull. Seismol. Soc. Am. 94, 591-597.

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