Dams could cause quakes
2002-05-07 17:16
Nairobi - Large development projects like dams and reservoirs around Africa's mountain areas could trigger earthquakes, volcanoes and landslides, a leading South African geologist said on Tuesday.
The effects of such natural disasters in future could be
aggravated by rising populations in vulnerable areas, according
Chris Hartnady, a former lecturer in Goelogical Sciences at the
University of Cape Town.
"Large areas of the African continent are in unstable,
tectonically active states and especially in the mountain regions" posing a "substantial danger" to the public, said Hartnady, who was attending a UN-sponsored Mountains High Summit Conference for Africa which opened in Nairobi in Monday.
Hartnady said that although mountain areas seeemed the best
places to build reservoirs or hydro-electric power projects, it had been observed that in eastern and southern Africa, the high-lying areas were usually associated with "tectonically active belts near faults and rifts in the Earth's crust".
Tremors
Massive pressure created by holding back millions of tons of
water behind a dam or in a reservoir could lead to earth tremors as was observed at the 185-metre Katse dam on the Maluti-Drakensberg mountains of Lesotho in October 1995.
A month after the dam was opened, residents of the neighbouring village Mapaleng Ha started to feel earth tremors.
Hartnady, now based at the Seismotectonic Consultancy in Kalk
Bay, South Africa, said that while African experts were aware of
the dangers posed by seismic activity, there was a need to
disseminate the information to the general public.
He warned that unless urgent action was taken by governments and planning authorities, the "economic cost of seismic and volcanic disasters" would escalate this century and hamper Africa's efforts at sustainable development.
Hartnady said Africa could benefit from relatively inexpensive
Global Positioning and Radar Satellite technologies to expand its
seismic mapping as a disaster-preparedness measure. - Sapa-AFP
- SAPA