Environmental archaeology of Disasters and　Land-developments．
We investigated disasters and land-developments in the Kawachi p1ains, 0saka prefecture．There facts were known，

1. There was the inland sea in the Kawachi plains about 6000 y.B.P. ago. It was larger than the sea that Kajiyama and lchihara reconstruct at 1970．The seashore invaded still more 3km，
2. There were many abandon channels in the Kawachi plains. Some abandon channels were before the eleventh century.　Others were after the eleventh century．They are distinguished by remote sensing，
3. We have four land-environment changing periods after 2300 y.B.P. It was known by plant-opal analysis. The Periods were 2100 y.B.P., 1700 y.B.P., 900 y.B.P. and　350 y．B.P.