Top: SFR for galaxy simulation g106, computed in bins of birth radius (left) and final radius (right), using the ten radial bins defined in Fig. 3. SFRs are measured in 1 Gyr-wide age bins, spaced by 0.2 Gyr, and have units of M_⊙ pc⁻² Gyr⁻¹. To select stars formed in the disk, for all plots we apply a vertical cut at birth, |z₀| ≤ 0.3h_d, where h_d is the disk scale length. To improve visibility across bins, the vertical axis is normalized to the second innermost bin. Bottom: absolute difference between the SFH computed from birth and final radii, ∆SFR = SFR(R_birth) − SFR(R_final), shown on the left, and the corresponding fractional difference, ∆SFR_fr = ∆SFR/SFR(R_birth), shown on the right. The largest absolute discrepancies occur in the inner disk at early times (red and orange curves, bottom left), whereas the fractional differences can exceed 200% in the mid and outer disk. The vertical dotted lines mark the first three pericentric passages of the last massive gas-rich merger. The shaded regions indicate the disk response to later dry mergers and a phase of ongoing minor interactions. These external events coincide with pronounced features in ∆SFR and ∆SFR_fr, highlighting their role in triggering both enhanced star formation and accelerated stellar migration (see Fig. 5 for the corresponding dynamical signatures).