On April 11th, 1690 the country village of Boesimo, in the Romagna Apennines (Lamone Valley, Ravenna, Italy), was subject to a large landslide, whose foot dammed the Lamone River and its right-side affluent Rio Boesimo, forming two separate lakes at the same time. Such a peculiar event raised the attention of several learned men of the time. The first one was Marco Antonio Melli, a physician from Faenza, who dealt with the disaster in two Latin pseudo-scientific works published in 1693 and 1708. This Author gave a wrong interpretation of the landslide, as the manifestation of an earthquake. Nevertheless, Melli's ocular witness remains very important, as it carefully accounts for the damaged properties (four destroyed houses), and the concurrent casualties (ten farmers). Moreover, both Melli's books are illustrated by a "panoramic" engraving, which portraits the landslide immediately after its emplacement. At the beginning of the XIX century, the abbot Giovanni Battista Tondini dealt with the same landslide, in order to demonstrate that the family of Evangelista Torricelli (the barometer inventor) was related to one of the destroyed houses ("La Torricella"). In his extensive manuscript Tondini added new data, and partly amended Melli's misinterpretation. Our integrate study of geologic, geomorphic, historical and toponymic data focuses at the geometry and development of the 1690 landslide, in relationship to the evolution of the Lamone and Boesimo obstruction lakes. The landslide, which involved 30000000 mc of turbiditic marls and sandstones (Marnoso-arenacea Fm), can be classified as a composite rock-slide, mostly controlled by the bedding planes attitude. In its present-day dormant state, the landslide still has a clear morphology, although its foot and sides have been deeply cut by stream erosion (leading to a volume loss of 6000000 mc). The intrinsic causes of the 1690 landslide depend on the downslope dip and the mechanical weakness of some stratigraphic levels. The preparatory causes depend on fracture loosening, weathering and local stream erosion. In turn, fracture loosening may have been enhanced by seismic activity, as for instance the historically documented 1661 and 1688 earthquakes. The triggering mechanism of the 1690 landslide is probably linked to heavy rainfalls, increasing the groundwater pressure in the collapse-prone hillslope. Indeed, winter 1689-1690 was associate to a wet stage in a longer period of climatic deterioration (1550-1850).
LANDUZZI A., PIASTRA S. (2004). THE 1690 LANDSLIDE AT BOESIMO, ROMAGNA APENNINES, ITALY. AN INTEGRATE GEOLOGIC-HISTORICAL APPROACH. FLORENCE : s.n.
THE 1690 LANDSLIDE AT BOESIMO, ROMAGNA APENNINES, ITALY. AN INTEGRATE GEOLOGIC-HISTORICAL APPROACH
LANDUZZI, ALBERTO;PIASTRA, STEFANO
2004
Abstract
On April 11th, 1690 the country village of Boesimo, in the Romagna Apennines (Lamone Valley, Ravenna, Italy), was subject to a large landslide, whose foot dammed the Lamone River and its right-side affluent Rio Boesimo, forming two separate lakes at the same time. Such a peculiar event raised the attention of several learned men of the time. The first one was Marco Antonio Melli, a physician from Faenza, who dealt with the disaster in two Latin pseudo-scientific works published in 1693 and 1708. This Author gave a wrong interpretation of the landslide, as the manifestation of an earthquake. Nevertheless, Melli's ocular witness remains very important, as it carefully accounts for the damaged properties (four destroyed houses), and the concurrent casualties (ten farmers). Moreover, both Melli's books are illustrated by a "panoramic" engraving, which portraits the landslide immediately after its emplacement. At the beginning of the XIX century, the abbot Giovanni Battista Tondini dealt with the same landslide, in order to demonstrate that the family of Evangelista Torricelli (the barometer inventor) was related to one of the destroyed houses ("La Torricella"). In his extensive manuscript Tondini added new data, and partly amended Melli's misinterpretation. Our integrate study of geologic, geomorphic, historical and toponymic data focuses at the geometry and development of the 1690 landslide, in relationship to the evolution of the Lamone and Boesimo obstruction lakes. The landslide, which involved 30000000 mc of turbiditic marls and sandstones (Marnoso-arenacea Fm), can be classified as a composite rock-slide, mostly controlled by the bedding planes attitude. In its present-day dormant state, the landslide still has a clear morphology, although its foot and sides have been deeply cut by stream erosion (leading to a volume loss of 6000000 mc). The intrinsic causes of the 1690 landslide depend on the downslope dip and the mechanical weakness of some stratigraphic levels. The preparatory causes depend on fracture loosening, weathering and local stream erosion. In turn, fracture loosening may have been enhanced by seismic activity, as for instance the historically documented 1661 and 1688 earthquakes. The triggering mechanism of the 1690 landslide is probably linked to heavy rainfalls, increasing the groundwater pressure in the collapse-prone hillslope. Indeed, winter 1689-1690 was associate to a wet stage in a longer period of climatic deterioration (1550-1850).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
