To quantitatively display the earthquake-proofness performance of a building and the effects of earthquake-proofness enforcement, by comparative examination of vibration characteristics, before and after repairing.

Vibration characteristics of a building are calculated, using simultaneous measurement data of the ground and building under minute vibrations, at all times, and the building is diagnosed for earthquake-proofness, based on the vibration characteristics of the building. After upgrading for earthquake-proofness in accordance with this, the earthquake-proofness performance and the effects of earthquake-proofness reinforcement of the building are displayed quantitatively, by comparative examination of vibration characteristics, before and after the upgrading.