Left raise-hand radical anchors 振 in the manual-action family - here a vigorous shaking or raising motion. 振 belongs to the energising-verb cluster with 挥 wave, 揭 lift, 提 raise. The hand drives the active sense across 振动 vibrate, 振奋 rouse spirits.
Right 辰 supplies the sound - chén drifting to zhèn through regular onset shift. Same phonetic appears in 震 quake (大地震 earthquake), 娠 pregnant, 唇 lip. 辰 itself depicts a clam or stirring tool; in 振 it works purely as the sound-bearer, while the hand carries the active "shaking" meaning.
