MANYARA, Hanang: THE deadly mudslide that claimed 65 lives and left 115 others injured in Hanang District; Manyara Region was caused by saturated cohesionless soil, a preliminary investigation has shown.
The Chief Government’s Spokesperson, Mr Mobhare Matinyi said yesterday that disaster was caused by collapse of some parts of Mount Hanang that failed to withstand the compression triggered by weak rocks ‘volcanic sediments’ after absorbing water.
“The geologist from the Ministry of Mineral conducted a survey since the day of the incident (December 3 this year) and preliminary information shows that the source of the disaster was the collapse of part of the Mount Hanang that is featured with soft rocks that absorbed water and eventually causing a mudslide,” Mr Matinyi told the media in Manyara Region.
“After absorbing water, it created the compression that made some part of the mountain unable to withstand the compression and eventually part of it collapsed, sending tonnes of muddy waters that carried with it uprooted trees and rocks downstream towards Jordom River,” he explained.
Mr Matinyi said the river could not withstand, breaking its banks as it poured muddy waters engulfing Katesh town and nearby villages.
He said Mount Hanang is made of soft rocks known as volcaniclastic sedimentary rocks. Mr Matinyi said that the government has made the follow up on the earthquakes report from September this year until the day of the incident and found out that there was no earthquake or volcanic eruption.
Matinyi further said geologists are conducting further investigations to see if the area will continue to face the disaster in future.
Speaking to the ‘Daily News’ on Monday, Geological Survey of Tanzania (GST)’s Head of the Natural Disasters Unit at the Geological and Mineral Research Institute of Tanzania Gabriel Mbogoni, explained that soil saturation, often induced by prolonged light rainfall, is a significant factor leading to mudslides.
“People may wonder why there hasn’t been heavy rainfall. Why the mudslide? Essentially, heavy and rapid rainfall is not as problematic because water flows swiftly downstream, particularly towards valleys.
However, light and prolonged rainfall penetrates the ground, saturating the soil and leading to mudslides,” clarified Mbogoni.
Mbogoni also stated that geological knowledge can contribute significantly to people taking precautions regarding areas for settlements and conducting various activities.
He added that GST is currently conducting assessments to create a map showing rock types and locations suitable for settlements around the country.
“We have now assessed 97 per cent of the country’s land to provide accurate information on rock types and land, helping individuals and institutions avoid building in hazardous areas,” Mr Mbogoni said.
Adam Kihaka, an environmental expert and instructor at the Mwalimu Nyerere Memorial Academy, explained in an interview with TBC1 that environmental degradation is a significant factor leading to soil erosion.
Kihaka linked environmental degradation to excessive rainfall, floods, and various natural disasters.
“Occurrence of mudslides is a global challenge resulting from worldwide environmental degradation, particularly in vulnerable areas like valleys or mountainous slopes,” he said.
Kihaka called on citizens to take precautions and authorities to issue early warnings, especially during seasons with anticipated heavy rainfall. He stressed the importance of heeding professional advice from meteorological authorities.
Social affairs analyst Dr Ahmed Sovu commended the swift response of the government following the disaster. He urged all Tanzanians to contribute to rescue efforts, emphasising that disasters like those in Hanang affect the entire nation.
Landslides on Mount Hanang previously occurred in the early 2000s, and during that time, GST identified water-saturated soil as the primary cause of mudslides in the area.