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Claim: An X user posted that the proliferation of boreholes in Nigeria has made the country susceptible to future earthquakes.
Verdict. MISLEADING. Studies and experts reveal that despite tremors, Nigeria is seismically stable and not prone to earthquakes because of indiscriminate borehole drilling.
Full Text
With a population of over 200 million people, less than 30 per cent of Nigerians have access to potable water. While it falls under the purview of governments at all levels to provide this, the reverse is the case, as citizens have resorted over the years to water supply by drilling boreholes.
Prospective property owners in the country consider boreholes necessary, given the government’s failure to provide potable water for its citizens. The government’s failure to provide water for citizens in many communities has stimulated borehole drilling across the country.
An X user, Temi (@_IamTipTop), posited that the proliferation of boreholes in Nigeria has made the country susceptible to future earthquakes.
This post made on April 02, 2024, was reposted by Instablog9ja (@instablog9ja) on the same day with the caption “Earthquake to hit Nigeria in the future due to the skyrocketing number of boreholes — Engineer.”
As of Friday, March 5, 2024, this post had gained over 9,000 likes, 1,400 comments, 1,400 retweets, and over 2 million views.
This claim has attracted various comments from application users who were either in support or against the claim.
“This is false. The hole made to extract water (borehole) is too small. Even if there were one in every compound, it would not cause an earthquake in the future.”
Nigeria has a lot of rainfall that wet the ground, and the soil is rocky and thick, preventing seismic pressure and rock movements. If a borehole is abandoned, constant rainfall will fill it up,” according to freedompedia.
“Earthquakes can be man-made and also natural. When there is a displacement of rock on or within the earth’s crust, it can trigger the release of energy which can cause earthquakes or tsunamis. However, earthquakes are associated with fault zones with hotspots,” according to Michael Godwin (@PetrologistMiky).
This claim has generated much controversy. Moreover, with the increasing rate of boreholes across the country, the assertion has become of immense concern to citizens, hence the need for verification by DUBAWA.
Verification
DUBAWA first conducted a keyword search and found a report by Thisday newspaper titled “LESSONS FROM TURKEY’S EARTHQUAKES,” published on Feb. 24, 2023. The story reported the findings of the federal government’s presidential assessment committee, which revealed the dangers inherent in various human activities, like unregulated drilling and blasting of rocks by quarrying companies and artisanal miners. However, the Nigerian Geological Survey Agency and other emergency agencies have downplayed the likelihood of an earthquake in Nigeria at the time of the report.
Olaoluwa Akintorinwa, a professor of Exploration Geophysics and Head of the Department of Exploration Geophysics at the Federal University of Technology Akure, said Nigeria is seismically stable. In a seismically stable area, earthquakes occur very rarely.
“Nigeria is not prone to earthquakes, but there may be a little tremor due to some of our activities like blasting,” he said.
He defined Isostasy as the tendency of the earth to maintain balance. Isostasy can be disturbed, but because Nigeria is seismically stable, it can only lead to tremors, not earthquakes.
Afolabi Olaoluwa, an Applied Geophysicist from Obafemi Awolowo University in Ile-Ife, confirmed that the proliferation of boreholes cannot trigger earthquakes. The point at which an earthquake is triggered is in the neighbourhood of kilometres, about 1 to 5km; boreholes, especially in the basement complex, are hardly deeper than 100 or 200 meters at most 250 meters but are not expected.
So, when the depth of termination of boreholes is considered, it is not close to what can trigger an earthquake. Highly compressed air in the vicinity of the drilling of the borehole could make the lateritic layer vibrate, which might be hazardous to buildings in the immediate periphery of that borehole. Though it is not common, it can not trigger an earthquake.
A Federal University of Agriculture lecturer, Abeokuta, Biodun Badmus, said that drilling many wells or boreholes in a specific area cannot cause an earthquake. Mr Badmus said this at the celebration of the Association of Water-Well Drilling Rig Owners and Practitioners’ 10th anniversary and inauguration of the Ogun State executives in Abeokuta, the state capital.
According to him, available data showed that drilling boreholes had nothing to do with earthquakes, adding that “there wouldn’t be tremor.” He, however, said the lack of adequate geographical surveys was responsible for the failure to get water after digging boreholes.
Contrary to Mr Biodun’s assertion, an earth scientist and lecturer at the University of Abuja, Ishaku Mallo, in a chat with THE WHISTLER, an online publishing platform, said that drilling boreholes could cause the ground to shake. At the same time, excessive water extraction can make the ground sink.
He added, “As you are drilling these boreholes into the ground, there is a vibration. These shaking vibrations can easily cause dislocation of the plates in the ground.
“Since drilling has brought cracks in the soil, the excessive groundwater extraction can make the ground sink. The sinking of the earth makes the ground move. Even if it goes down a little, it can cause the whole FCT to shake because the balance of the earth has been distorted,” he explained.
He warned, “People don’t realise that pressure on the environment has its negative effects. If you see a Thirty-year-old tree and you cut it, if you plant another one, it may take another thirty years to get to that point. Yet, there is indiscriminate felling of trees, digging of the ground, and indiscriminate making of dams.” All these things have negative effects on the environment.” He warned!
Mr Mallo was one of the 16-man team of experts invited by the Federal Government to investigate the remote causes of the tremor that occurred in Mpape and parts of Maitama District, in the nation’s capital city, sometime in 2018 to make far-reaching recommendations.
A review of earthquake occurrences and observations in Nigeria
According to the International Nuclear Information System (INIS), Nigeria is not located within the major seismic zones of the world; over the years, several minor earthquakes have been experienced in some parts of the country. The first widely reported occurrence of an Earth tremor in Nigeria was in 1933.
Other events were reported in 1939, 1964, 1984, 1990, 1994, 1997, 2000, and 2006. Based on the Modified Mercalli Intensity Scale, the intensities of these events ranged from III to VI. Of these events, only the 1984, 1990, 1994, and 2000 events were instrumentally recorded.
They had body wave magnitudes ranging from 4.3 to 4.5, local magnitudes between 3.7 and 4.2, and surface wave magnitudes of 3.7 to 3.9. When these events occurred, there were no functional seismological observatories in Nigeria.
The seismic activity in Nigeria is not confined to specific regions but is dispersed across the country’s six geopolitical zones. The South-West Zone seems to have experienced a higher frequency of earthquakes than other regions, making it particularly prone to seismic activity.
A study on earthquake-resistant construction (2013) revealed that in response to the recent earthquake in Morocco in September 2023, concerns have been raised regarding Nigeria’s susceptibility to similar seismic events.
Researchers and organisations, such as the Nigerian Association of Water-Well Drilling Rig Owners and Practitioners (AWDROP), have called upon the Nigerian government to limit or reduce the potential impact of earthquake aftermath.
Adepelumi Abraham and his team from the Department of Geology at Obafemi Awolowo University warned of an impending danger, predicting a significant earthquake in Shaki, located in the southwest of Nigeria.
AWDROP has also drawn attention to the potential link between underground water extraction and induced earthquakes, advocating for strict compliance with implementing the code of practice.
Seismic faults in Nigeria
Studies in geophysics have identified the presence of active seismic faults in Nigeria, shedding light on the country’s vulnerability to earthquakes. Notably, the Ifewara-Zungeru fault has been recognised due to its prominent presence in the South-West region of Nigeria. This fault, a thick black line on the Nigerian map, extends through the Ifewara zone.
However, it’s essential to acknowledge that Nigeria’s dispersed seismic activities may suggest other possible fault lines. The Anka, Jushi Kwari-Akko, Dambata-Akko, and Kalangai faults are among these potential fault lines. The prevailing belief is that future earthquakes in Nigeria will likely occur along these existing fault lines.
Likely causes for earthquake occurrence
Once considered a seismically stable region, Earthquakes in Nigeria have raised questions about the underlying causes. Researchers have explored several theories to elucidate why Nigeria experiences earthquakes.
One prevailing theory suggests that the stresses generated between the African plate and the southern American plate exert pressure on the coastal areas of Nigeria located within this boundary. These stresses, induced by the movements of these tectonic plates, can be transmitted to Nigeria, leading to earth tremors along fault lines within the country.
Additionally, geological factors play a role in seismic activity in Nigeria. Some believe that the country’s geological location, shaped by orogenic deformations along the cratons over the years, contributes to the tremors experienced in the region.
These ancient geological processes may continue to influence the country’s seismic activity.
While Nigeria may not be classified as a high-seismic region like countries along plate boundaries, it is essential to recognise that the nation is not immune to earthquakes. Until recent years, seismic data collection in Nigeria faced limitations, leaving gaps in the country’s understanding of earthquake activity.
However, that has now changed with the establishment of a seismographic network managed by the Centre for Geodesy and Geodynamics (CGG), Toro, Nigeria. The network has four operational stations with 24-bit 4-channel recorders and broadband 30-second seismometers.
Earthquake Forecast in Nigeria
Recent seismic alerts and warnings have drawn attention to Nigeria’s earthquake vulnerability, challenging the notion that the nation is seismically stable. In response to the recent Morocco earthquake incident in September 2023, these forecasts have sparked discussions on the extent and probability of future earthquakes in the country.
One notable earthquake forecast has raised concerns about seismic activity in Nigeria. The forecast suggests that a significant earthquake of ≥ 5.0 will likely occur in the South-West part of Nigeria between 2010 and 2028. What is particularly striking is the probability associated with this forecast, which escalates from 6% to a substantial 91.1% within this time frame. Researchers have undertaken extensive studies to address the knowledge gaps and uncertainties regarding the extent of probable future earthquakes in Nigeria (Ofuyatan et al., 2018).
Their research characterises Nigeria as a country with low seismicity. Still, their findings point to the potential for significant earthquakes, including those with magnitudes as high as 7.2, especially in the southwest region.
While some may question the likelihood of Nigeria, categorised as a low-seismic country, experiencing such substantial earthquakes, it’s essential to remember that seismic events can occur unexpectedly even in regions traditionally considered low-risk. For instance, Antarctica, an area historically known for its minimal seismic activity, experienced an earthquake with a magnitude of 8.1 in 1998.
Conclusion
Our findings show that the claim that Nigeria might experience earthquakes due to the indiscriminate drilling of boreholes in the country is misleading.
