Is it due to the longitudinal nature of the seismic waves?
When a heavy bus or truck goes by at high-speed, the shaking in nearby ground is not mistaken as dizziness, rather the feet and body feel a vertical jerk (seemingly a transverse wave vertical to the ground).
But when a natural, mild earthquake takes place, it is not felt as a jerk or switch in a direction at all. Rather we feel it for a while as dizziness. I have experienced this, and heard of many others who have as well. In-fact it takes a few seconds to distinguish whether it is dizziness or an earthquake.
Is it due to the longitudinal waves? Is it because they are horizontal with the ground, matching the direction of dizziness?
Does this phenomenon's frequency act similarly to the motion and simulates dizziness?