594
Climatic Geomorphology
Figure 22.9. Bridge fallen into the Cocos River as a consequence of floods associated with the Mitch
hurricane, during the end of October and beginning of November of 1998, North of Nicaragua, near the
Honduras frontier. Photo: A. G6mez Sal.
water addition transformed the pyroclastic deposits into a debris flow, which spread out
through the croplands existing at the volcano foot. Numerous settlements were buried,
causing around 1500 deaths. The debris flow thickness was estimated to be about 2 m
(personal communication from Prof. A. Cendrero) (Figure 22.10).
Slope failures constitute periodic and catastrophic erosive processes in some zones. The
region between Sao Paulo and Rio de Janeiro in Brazil is crossed by the abrupt ridges of
Serra do Mar and Mantiqueira, separated by the Val Paraiba valley. Catastrophic failures
have been recorded in 1942, 1956, 1966, 1967, and 1988. As a consequence of the floods
and slides of 1942, governmental measures were established in relation to construction
practices, forest conservation, and soil use. In March 1956, the city of Santos was affected
by heavy rains, with a maximum intensity of 250 mm in 10 h, that triggered numerous
rotational and translational slides (Pichler, 1958). In January 1966, Rio de Janeiro
experienced rainfall of 472 mm in 72 h and produced mass movements such as rock falls,
mud flows and rotational slides (Tricart, 1974a). The disaster produced 1000 deaths. The
most spectacular slope failure development in this region took place in the steep Serra das
Araras, which forms part of the Serra do Mar and is located 50 km West of Rio de Janeiro.
On the 22nd and 23rd of January 1967, 275 mm of precipitation occurred with an intensity
of 114 mm/h, accompanied by strong thundering, which triggered more than 10,000
failures in a 180 km 2 area. There were debris slides, debris avalanches, and mud flows that
affected water and power supplies and road traffic, cutting the Sao Paulo-Rio de Janeiro
highway. About 1700 people died and material losses were estimated at 1600 million
dollars (Jones, 1973). Finally, in February 1988, debris avalanches in Rio de Janeiro killed
200 people, and 20,000 lost their homes (Smith and de Sfinchez, 1992).
Climatic Geomorphology
Figure 22.9. Bridge fallen into the Cocos River as a consequence of floods associated with the Mitch
hurricane, during the end of October and beginning of November of 1998, North of Nicaragua, near the
Honduras frontier. Photo: A. G6mez Sal.
water addition transformed the pyroclastic deposits into a debris flow, which spread out
through the croplands existing at the volcano foot. Numerous settlements were buried,
causing around 1500 deaths. The debris flow thickness was estimated to be about 2 m
(personal communication from Prof. A. Cendrero) (Figure 22.10).
Slope failures constitute periodic and catastrophic erosive processes in some zones. The
region between Sao Paulo and Rio de Janeiro in Brazil is crossed by the abrupt ridges of
Serra do Mar and Mantiqueira, separated by the Val Paraiba valley. Catastrophic failures
have been recorded in 1942, 1956, 1966, 1967, and 1988. As a consequence of the floods
and slides of 1942, governmental measures were established in relation to construction
practices, forest conservation, and soil use. In March 1956, the city of Santos was affected
by heavy rains, with a maximum intensity of 250 mm in 10 h, that triggered numerous
rotational and translational slides (Pichler, 1958). In January 1966, Rio de Janeiro
experienced rainfall of 472 mm in 72 h and produced mass movements such as rock falls,
mud flows and rotational slides (Tricart, 1974a). The disaster produced 1000 deaths. The
most spectacular slope failure development in this region took place in the steep Serra das
Araras, which forms part of the Serra do Mar and is located 50 km West of Rio de Janeiro.
On the 22nd and 23rd of January 1967, 275 mm of precipitation occurred with an intensity
of 114 mm/h, accompanied by strong thundering, which triggered more than 10,000
failures in a 180 km 2 area. There were debris slides, debris avalanches, and mud flows that
affected water and power supplies and road traffic, cutting the Sao Paulo-Rio de Janeiro
highway. About 1700 people died and material losses were estimated at 1600 million
dollars (Jones, 1973). Finally, in February 1988, debris avalanches in Rio de Janeiro killed
200 people, and 20,000 lost their homes (Smith and de Sfinchez, 1992).