An Improved Multidimensional MPA Procedure for Bidirectional Earthquake Excitations

Figure 2

The spectra of 𝑅_𝑏/𝑅_𝑠 for the three kinds of soil sites.

(a) Hard soil site, 𝛾>0, 𝜇=2

(b) Intermediate soil site, 𝛾>0, 𝜇=2

(c) Soft soil site, 𝛾>0, 𝜇=2

(d) Hard soil site, 𝛾<0, 𝜇=2

(e) Intermediate soil site, 𝛾<0, 𝜇=2

(f) Soft soil site, 𝛾<0, 𝜇=2

(g) Hard soil site, 𝛾>0, 𝜇=4

(h) Intermediate soil site, 𝛾>0, 𝜇=4

(i) Soft soil site, 𝛾>0, 𝜇=4

(j) Hard soil site, 𝛾<0, 𝜇=4

(k) Intermediate soil site, 𝛾<0, 𝜇=4

(l) Soft soil site, 𝛾<0, 𝜇=4