The acceleration arrow direction is for up and down along that axis.
Your model has a mistake, the acceleration is 14.2 m/s^2 You typed 12.4 mm/s^2.
Insert a Frequency Response for Displacement of a vertex at the fixed end and you will see the 0.4 mm amplitude at 30 Hz.
The amplitude is high because you did not include any Damping in the model.
You have to enter some amount of damping, say Damping Ratio = 0.01 = 1%
With 0% Damping Ratio, there is a 267 mm displacement at the tip at 24 Hz.
With 1% Damping Ratio, there is a 48.7 mm displacement at the tip at 24 Hz.
With 2% Damping Ratio, there is a 24.7 mm displacement at the tip at 24 Hz.
Keep in mind that this is a linear analysis. When the deflections get too large, the small rotation assumption in the linear model is no longer valid. In that case, you have to perform a Full Transient and turn on Large Deflection in order to see the true deformation.
Also, Insert a Mesh Control Method called Multizone on the body.