The Government has been asked to close the Mai Mahiu-Narok road and suspend any development projects in the southern rift to prevent loss of life.
The scientists from the University of Nairobi (UoN) and the Institute for Meteorological Training and Research said the cracks were a sign of hidden and potent activity in the Rift Valley.
The road developed large cracks at Suswa on March 13. The road was reopened after the Kenya National Highways Authority filled up the cracks using rocks and repaired it.
Eric Odada, the head of UoN's African Collaborative Centre for Earth System Science, said the Rift Valley was unstable and any sign of geological activity should be dealt with immediately.
“The Narok-Longonot-Naivasha-Elementaita-Nakuru-Magadi area of the Rift Valley is very unstable. This is the reason we see Mt Longonot releasing fumes and Lake Magadi experiencing 300 earthquakes in a year. When we see cracks occurring, we should be worried,” he said.
Noting that the Kenyan Rift Valley was the largest opening in the world, Prof Odada warned that the instability caused by tectonic and seismic movements was a ticking time bomb.
“Lakes Nakuru, Naivasha, and Elementaita were one big lake, with the deepest part being at Kariandusi. They separated because of volcanic activities like the ones we are witnessing at Suswa,” Odada said.
“The crack can be as deep as five kilometres. Or when the Rift Valley moves up, it creates ridges like the Kabete ridge in Kiambu. When this happens, it can cause a major collapse of land or opening of a craven and sink villages in a few minutes.”
The professor pointed out that lakes in the Rift Valley were formed through similar movements of tectonic rocks.
He urged the Government to stop any developments in the affected area, saying that even the colonialists did not invest in infrastructure there.
Volcanic ash
“This matter should be taken seriously. I shudder when I see vehicles still being allowed to use the Nairobi-Narok road. Even the Maai Mahiu road should be closed and people moved to safer areas,” Odada said.
He added that the British avoided building roads or railway lines in the Narok region due to volcanic activity.
“The British knew the dangers of such developments and used the more stable road from Nairobi through Nakuru to Kericho. The massive infrastructure we are seeing in this area where land is being excavated poses more risks,” Odada said.
George Krhoda, a professor of geography and environmental studies at UON, said the surface of the earth has many cracks that begin to manifest during rainy seasons.
“The Rift Valley has many cracks filled with volcanic ash. When it rains, the cracks are filled with water and become wet. Due to changes in land use that causes water run-off and erosion, the water finds such openings and cleans them, causing the cracks,” Prof Krhoda said.
He added that the hot lava in Mt Longonot has been rising for the past 30 years and that volcanic ash and fine soil particles make the area in the southern rift belt (Nakuru-Naivasha-Narok) susceptible to cracks.
More stable
“This is the opposite of Baringo and Turkana, which are more stable because of rocks. Though Kenya has not been associated with earthquakes, which are more common in Tanzania and Rwanda, theses cracks should worry us,” Krhoda said.
Onyango Ogembo, a professor of geology at UON, called on the Government to involve professionals when designing development projects to avoid such challenges.
Water run-off
“The fractures at Suswa are caused by volcanic activity and the water run-off after rains. The immediate solution to the Suswa crack is erecting a suspension bridge over the crack and use culverts that can stand the pressure of the water. But water must be allowed to flow,” Prof Ogembo said.
Richard Muita, a meteorologist and lecturer at Nairobi’s Institute for Meteorological Training and Research, said geological and weather activities were related.
“During tectonic movements, the ground is wet and this fastens the cracking because the soil is moist and wet. This causes land and mudslides,” Mr Muita said.
However, the Government disagreed with the experts, saying the cracks were caused by floods and not tectonic movements.
The State said numerous studies done in the area had found that underground washing of soil had contributed to the phenomenon. It insisted that there was no evidence that the area was splitting.
Mining Principal Secretary John Omenge led senior Government officials from various departments on a fact-finding mission in the area.
Mr Omenge told journalists that the Government was alarmed by claims that the area was splitting due to tectonic movements. He termed the reports 'false and baseless'.
False information
Omenge accused geologists of fanning fear and giving out false information on what was happening in Suswa.
"We shall empower the Geologists Registration Board, which is headed by a director in the ministry, to come up with a data base of all qualified geologists in the country," he said.
