Mass Balances on Land

Different methods yield different values of modern erosion rates:Object: landslides; time span: 50 years. Precipitation data from 1936 to 1986 and estimates of the volumes of landslides on air photos from 1941, 1955 and 1973 result in an estimated erosion rate of about 2700 mm/ka.Object: sediment trap Lago Costantino; time span: 12 years. The volume of accumulated sediment corresponds to an estimated erosion rate of about 1900 mm/ka.Object: geodetic survey of the long profile; time span: 26 years. Accumulation along the river course led to an estimated erosion rate of 900 mm/ka, the amount lost to the ocean during this time not taking into account.Object: overall mass balance of the Buonamico [08]; time span: 50 years. The input into the Buonamico is estimated at 19 x 106 m3, the amount still stored along the river course may add up to 7.5 x 106 m3 solid rock equivalents. The difference, 11.5 x 106 m3, is obviously exported into the Ionian Sea. This corresponds to an erosion rate of 1527 mm/ka, seven times more than calculated from the 1 Ma mean.