Figure 3 Relaxation models adapted to the frequency recovery of
buildings for the different periods defined in Figure 2.
a , Normalized frequency variation over recovery time according
to the model proposed by Ref. 24. Here, a and G are proxies for
elasticity. \(m=\log\left(\frac{t}{\tau}\right)\). b,Normalized frequency variation over the recovery time according to the
relaxation function of Ref. 22. Here,
τmax/τmin is the ratio between the final
and initial relaxation times computed from the model. c,Relaxation spectra proposed by Ref. 23.