- Ground-motion model is:
where Ap is in cm∕s2 and for combined Yunnan and W. N. American data a = 1291.07, b = 0.5275,
c = -1.5785, Δ = 15 and σ = 0.5203 (in terms of natural logarithm).
- All records from basement rock.
- Most Yunnan data from main and aftershocks of Luquan and Luncang-Gengma earthquakes.
- Records from Lancang-Gengma sequence corrected.
- Most Yunnan records with 3 ≤ Ms ≤ 5 and 10 ≤ R ≤ 40km.
- To overcome difficulty due to shortage of large magnitude records and sample heterogeneous distribution
in near and far fields use W. N. America data, because intensity attenuation is similar.
- Fit curves to Yunnan and Yunnan with W. N. American data. Find curve for combined data has lower
variance and fit to observation data for large magnitudes is better (by plotting predicted and observed