There are various possible causes of the Aso Bridge failure, such as earthquake ground motion, slope failure, and ground displacement. Here, we evaluate the effect of primary and secondary soil failures near the Aso Ohashi Bridge, which is one of the most likely causes. Based on the topographic changes before and after the earthquake and measurement of vertical displacement by drone, 510 m² of soil per unit width (61,200 kN for 8 m width) is considered to have been transported downstream near the arch by the secondary and primary collapsed soils. It can be pointed out that the movement of these sediments may have caused the arch bridge to collapse.