Russian to English Tech/Engineering Geology soil properties

Not much useful context, it is the heading of a column in a table. The table is in a supplement to a set of instructions about making buildings more earthquake resistant. The supplement is called "Характеристики лессовых просадочных грунтов Прикопетдагской равнины". The table has two columns, the left-hand one headed "Площадь замачиваемого котлована, м2", and the right-hand one as above. For the first entry on the left "Менее 1", the entry on the right is "Просадки не проявляются". For the remaining figures on the left (5-320), the figures on the right are from 0.12 to 1.00.
It seems to me that the right-hand column must be subsidence in metres (from other data in the long main document, these seem reasonable figures for the subsidence which would occur over these areas). So I shall just call it "Subsidence, m", unless I can find some explanation of what this heading means that would cause me to change my mind.