- Ground-motion model is: All other fs are the same as fcr but without FR and FN. h is depth to top of rupture for events with
rupture geometry model and focal depth otherwise. xv is horizontal distance of path through volcanic zones
(straight line). SkNL is previously-published nonlinear site response term. gum is geometric attenuation
rate for upper-mantle events. gL is geometric attenuation rate for distances > 40km. cr is for crustal
events, um is for upper-mantle events, intS is for shallow subduction interface events, intD is for deep
suduction events with depth h > 25km and SL is for subuction slab events. Cmax = 7.1 as determined by
goodness-of-fit parameter. h1 = 25km and hintD = 50km.
- Use site classes of Zhao et al. (2006).
- Use three faulting mechanisms using definitions of Boore and Atkinson (2008):
- Reverse. Plunge of T axis > 40∘. Use FR.
- Normal. Plunge of P axis > 40∘. Use FN.
- Strike-slip. Other plunge angles.
- Develop functional form because of previous observations on effect of mantle wedge etc. on attenuation
- Purpose of model is to classify earthquakes into types rather than for ground-motion prediction. Hence
coefficients not reported.
- Use Slab1.0 subduction interface geometry model (Hayes et al., 2012) for classification schemes.
- Use some data from Alaska, California, Turkey and Iran, Taiwan and Wenchuan (China) to supplement
Japanese data for large crustal earthquakes and near-source distances.
- 31 Japanese earthquakes from before 1996 have Mw ≥ 6.5.
- Use maximum log-likelihood as goodness-of-fit measure because σ not very sensitive to the selection of
model parameters when they are close to the best solutions using a random effects model and maximum
log-likelihood sensitive to biased residual distribution and it is important to eliminate any bias in residuals
because models often extrapolated. Use Akaike information criterion to check if model parameter should
- Try 4 classification schemes and various combinations of earthquake catalogues. Find using locations from
the International Seismological Centre (ISC)/Engdahl et al. (1998) (EHB) for events before 2005 then
using locations of 1) Japan Meteological Agency (only those with high precision level), 2) ISC/EHB and
3) National Earthquake Information Center (excluding events with a fixed depth) for more recent events
produced best models in terms of maximum log-likelihoods. The best event classification is the following.
Classify reverse events, depth within 5km of interface, depth < 50km and dip angle for one of nodal planes
within 15∘ from interface dip angle as interface earthquakes. Classify events above the interface that are
not classified as interface and have depth ≤ 25km as shallow crustal earthquakes. Classify events above
subduction interface but are not shallow crustal earthquakes are upper-mantle events. Classify all other
earthquakes as subduction slab earthquakes. Note that this leads to highest maximum log-likelihood but
little reduction in σ. Also note that this classification does not guarantee correct classification and that
misclassification of a small number of events would not affect the goodness-of-fit parameters.