  E2 transitions in Si-30 are investigated in relation with intrinsic
deformations based on a method of antisymmetrized molecular dynamics. By
comparing E2 transition strengths in the mirror nuclei Si-30 and S-30,
transition matrix amplitudes M_p and M_n for protons and neutrons are discussed
in mirror analysis. Particular attention is paid to the M_n/M_p ratio in the
transition from the 2^+_2 state to the 0^+_1 state. The M_n/M_p ratio in Mg-26
and Si-26 is also investigated. It is found that the proton dominance in the
transition 2^+_2 -> 0^+_1 in Si-30 and Si-26 originates in the oblate trend of
the Z=14 proton structure.
