- Ground-motion model is: where Y in in cm∕s2, c0 = -2.376, c1 = 1.818, c2 = -0.1153, c3 = -1.752, σintra = 0.28, σinter = 0.24
and σtotal = 0.37.
- Adjusts data to NEHRP B/C boundary (V s,30 = 760m∕s) using site amplification term of Boore
et al. (2013). Suggests that this site amplification term can be used to evaluate model for other site
- Uses data from Next Generation Attenuation-West 2 with 3 ≤ Mw ≤ 6 and rhypo ≤ 40km that pass
selection criteria of Boore et al. (2013).
- Aim is a model for use in evaluating hazard from induced seismicity but use natural seismicity data because
induced seismicity data lacking. Assumes that ground motions of the two types are similar.
- Little data from rhypo < 10km, which means that control on distance saturation is uncertain. Hence use
heff from Yenier and Atkinson (2014) from stochastic modelling of global earthquakes with Mw ≥ 6.
Suggests that heff = 1km (corresponding to Mw4) is the lower limit that should be used. Tries alternative
functions for heff and note that they fit the data almost as well but lead to different very near source
predictions. This implies an epistemic uncertainty of up to a factor of two in the near-source area.
- Chooses functional form as simplest likely to be applicable.
- Finds that standard least-squares regression gives similar results.
- Plots predictions against observations grouped into 0.5Mw width bins. Finds good fit.
- Plots residuals w.r.t. rhypo and finds no trends, which means that a more complex functional form is not
- Note that model is strictly applicable only to about 40km because of lack of anelastic attenuation term.
Proposes adding a additional term c4R with c4 calibrated using the behaviour of the Boore et al. (2013)
model beyond 40km. For PGA c4 = -0.002 is proposed.