BY EDGAR TSIMANE
With an earthquake monitoring station capable of detecting nuclear explosions occurring as far as North Korea in place, scientists are now planning Botswana’s first seismological centre.
The Botswana Geoscience Institute (BGI) intends to build a nation-wide seismological centre to record and monitor earthquakes including mining induced tremors after the science institute benchmarked with its international collaborators.
It seems the scientific plan can work.
At Magotlhwane village about 70 kilometres south of Gaborone stands, on a bedrock of stable granite, an earthquake monitoring station that can detect nuclear test detonations occurring thousands of miles away.
“The seismic data collected at the Magotlhwane station is sent for archiving and use to both the United Nations body responsible for Nuclear-Test ban (CTBTO) and to the US Geological Survey. The data is also made available to the BGI,” said Onkgopotse Ntibinyane senior seismologist at the BGI.
The station is known as the Lobatse station. It belongs to the Global Telemetered Seismograph Network (CTSN). Coded LBTB, it is one of the global monitoring stations that record earth tremors and underground explosions. The LBTB station near Lobatse also contributes to monitoring of local seismic events.
It was partly funded by the US Air Force following the US and the Botswana governments’ memorandum of understanding spanning three decades.
Asked to detail this ambitious plan, Ntibinyane was short on details saying the whole idea is still at a conceptual stage.
“So far the BGI has consulted with local critical stakeholders and will continue to extend the consultations to other stakeholders both nationally and internationally. BGI has embarked on a bench-marking programme to the USA and other big seismological centres for best practice in setting up the centre.” said the seismologist.
Koketso Botepe BGI manager – Applied Geosciences would not go into budget estimates for the envisaged project better still he said: “More will unfold in the 2019/20 financial year. The Centre will most likely take the form of the UB’s Okavango Research Institute. It may or may not be physically be located at the BGI in Lobatse The cost still to be determined, but obviously the budget will run into millions of Pulas, but may have to be phased, depending on the priority areas.”
“Having such a centre will go a long way in guiding policy decisions with respect to earthquake monitoring, data storage, public education, establishment of emergency response teams, as well as the development of building codes in line with world standards for earthquake resilient and resistant structures. The center will also focus on state-of the-art technology on earthquake monitoring systems,” he said.
Of late the BCL mine in Selibe Phikwe has been experiencing a series of tremors which were felt on surface but whose magnitudes are unknown.
“The seismicity of the BCL mine is not monitored by the BGI. However, the BGI is operating a country-wide seismic network of stations that regionally cover Selebi-Phikwe area. Mining induced-seismicity requires a local network array that is designed to pick micro-tremors (small magnitude), which the BGI is currently not doing. Should a major earthquake occur within the Phikwe area, the BGI’s country-wide network will detect it,” said Ntibinyane
He said due to the micro-tremors reported in Phikwe, the BGI is working with the Department of Mines and the mine to deploy a local seismic monitoring in the town.
“The current constrain is that BGI does not have the right equipment and hence will consider outsourcing the services,” said Botepe.
Scientists at the institute say all countries are prone to earthquakes.
Botswana registered a series of earth tremors in 2017 the largest being a 6.5 local magnitude on the Richter scale on 3 April of the same year which occurred at the Central Khalahari Game Reserve.
“A series of the earthquake aftershocks followed. The BGI in collaboration with the South African Council for Geoscience deployed temporary seismic monitoring stations in the epicentral region of the earthquake for a period of three months. “Earthquakes cannot be precisely predicted, but the country will be zoned into different areas depending on vulnerability and possible impacts. That in itself is fore-warning,” said Ntibinyane.
He added that Botswana has learnt from previous earthquakes.”We need a dense monitoring network of stations and that the country has to be adequately resourced in terms of seismic monitoring.”
To detect and accurately locate earthquakes in Botswana and the surrounding areas the BGI operates a national seismic network known as the Botswana Seismological Network (BSN) with 21 seismic stations deployed country-wide.
The network has 18 of the stations telemetered to transmit data near-real time to the BGI headquarters in Lobatse where the seismologists processes it and interpret it.
The data recorded from this station is transmitted to both the United States Geological Survey and the International Data Center.
Ntibinyane said the BGI is working on the expansion of the seismic monitoring to mining, dams and other active areas such as the Okavango Delta Region. To help in deriving Seismic Building Codes with liaison with engineers, architects and planners on constructing earthquake resilient infrastructures
Establishment of Seismological research Center is expected to serve as a national Seismological Observatory and in alignment with the BGI’s core mandate of undertaking cutting-edge research in seismology and to act as an advisory body in respect of seismic-related geo-hazards.