- Ground-motion model is:
_{8}= -0.1091, a_{9}= 0.0937, a_{2}= 0.0029, a_{5}= 0.2529, a_{6}= 7.5 and a_{7}= -0.5096 for all distance metrics; a_{1}= 1.85329, a_{3}= -0.02807, a_{4}= -1.23452, ϕ = 0.6201 (intra-event), τ = 0.3501 (inter-event) and σ = 0.7121 (total) for r_{jb}; a_{1}= 2.52977, a_{3}= -0.05496, a_{4}= -1.31001, ϕ = 0.6375 (intra-event), τ = 0.3581 (inter-event) and σ = 0.7312 (total) for r_{epi}; a_{1}= 3.26685, a_{3}= -0.04846, a_{4}= -1.47905, ϕ = 0.6475 (intra-event), τ = 0.3472 (inter-event) and σ = 0.7347 (total) for r_{hypo}; V_{REF }= 750m∕s, V_{CON}= 1000m∕s, b_{1}= -0.41997, b_{2}= -0.28846, c = 2.5 and n = 3.2 are from Sandikkaya et al. (2013). - Use V
_{s,30}to characterise sites. Most sites classified in Eurocode 8 classes B and C, i.e. 180 ≤ V_{s,30}≤ 800m∕s. Note limited data from V_{s}> 800m∕s. Use nonlinear site amplification model of Sandikkaya et al. (2013) for model. Recommend model for 150 ≤ V_{s,30}≤ 1200m∕s. - Focal depths between roughly 0 and 29km. No dependency on mechanism. Vast majority of earthquakes
with M
_{w}> 6 have depths < 20km and distribution for smaller events roughly uniform. - Data from 322 stations.
- Use 3 mechanisms:
- Strike-slip
- F
_{N}= F_{R}= 0. - Normal
- F
_{N}= 1, F_{R}= 0. Most data from this mechanism. - Reverse
- F
_{R}= 1, F_{N}= 0. Relatively few records.

- Derive using RESORCE (Akkar et al., 2014c) as part of special issue (Douglas, 2014) including 4 other ground-motion models (Douglas et al., 2014).
- Most data from Italy, Turkey and Greece but believe models can be used for seismically-active areas in S. Europe and Middle East.
- Derive models using r
_{jb}, r_{epi}and r_{hypo}so as to avoid requirement for distance conversion or virtual faults when using the models in probabilistic seismic hazard assessments. - Include records from aftershocks because: difficult to classify European events into mainshocks and aftershocks, about half records come from aftershocks, and there is limited evidence for differences in motions for European data (Douglas and Halldórsson, 2010). Note that this inclusion could increase σ.
- Note that possible bias in data at great distances because of trigger thresholds but conclude, based on
predictions from previous model and various instrument resolutions, that data roughly unbiased for M
_{w}> 4 and r_{jb}< 200km. - Exclude data from 163 singly-recorded events so as not to inflate τ (inter-event variability).
- Only include data from 3-component accelerograms so that a consistent model for vertical-to-horizontal spectral ratio can be derived.
- Remove events with M
_{w}< 5 with < 3 records to make the distribution w.r.t. mechanism more uniform and to prevent small events dominating derivation of mechanism terms. - Note that data covers M
_{w}≤ 7 well, particularly for normal and strike-slip mechanisms. For M_{w}> 7 almost no records from normal and reverse events and most data from 3 strike-slip earthquakes: 1990 Manjil, 1999 Kocaeli and 1999 Düzce. - Undertake trial regressions adjusting motions to V
_{s,30}= 750m∕s using nonlinear site amplification model of Sandikkaya et al. (2013) to choose functional form. Also regress using simple site classes to check Sandikkaya et al. (2013) and find similar results. Consider quadratic, cubic and hinged magnitude scaling and visually compare observations and predictions and study reduction in τ (inter-event). Impact on τ was limited so mainly use visual comparisons. Plot predicted and observed ground motions scaled to r_{jb}= 10km and V_{s,30}= 750m∕s against M_{w}. Find similar results for M_{w}< 6 and significant differences for M_{w}> 7. Find oversaturation predicted by cubic model that is not seen in data. Find hinged magnitude scaling best matches observations but note that this is somewhat unconservative and higher epistemic uncertainty at these magnitudes because of lack of data. - Try including anelastic attenuation term but find non-physical positive coefficients so remove it.
- Try including magnitude-dependent distance saturation but find similar predictions and no significant impact on σ. Hence remove it to reduce number of coefficients.
- Do not consider effect of depth to top of rupture because of limited information.
- Find that a
_{2}, a_{5}, a_{6}and a_{7}show little variation with T and hence make them period-independent coefficients, which leads to smooth spectra. - Find mechanism coefficients a
_{8}and a_{9}are very similar for three distance metrics so use same coefficients for r_{jb}, r_{epi}and r_{hypo}. - Plot residuals, grouped into bins, w.r.t. M
_{w}, R and V_{s,30}. Intra-event residuals do not show trends. Find model overestimates observations for V_{s,30}< 180m∕s and underestimates short-period motions for V_{s,30}> 800m∕s. But note that data in these bins are sparse and poorly distributed. Inter-event residuals suggest some bias for large magnitudes. Narrowing in residuals for large magnitudes could suggest magnitude-dependent σ but note sparse data for M_{w}> 7. Decide not to model magnitude-dependent σ since apparent dependency in residuals could be due to uncertain metadata (particularly M_{w}) for smaller events and data from only handful of events for M_{w}> 6.5 leading to underestimation of true σ here. - Note that σs for r
_{epi}may underestimate true variability because of lack of data from M_{w}> 6 and r_{jb}< 15km for which the impact of using r_{epi}rather than r_{jb}is largest. - Note possible overprediction of motions for M
_{w}< 5 based on comparisons to previous models. - Note uncertainty in model beyond the data (M
_{w}> 7.6) but believe that can be used up to M_{w}8 based on comparisons to other models. - Note that extrapolation to r
_{jb}> 200km can be done with some caution.