Preparing Nigerian buildings for possible earthquakes

A Non-Government Organisation, Building Collapse Prevention Guild (BCPG) in this treatise by its National President, Kunle Awobodu, a builder, and National Publicity Secretary, George Akinola, an Architect, write on possibility of Nigeria experiencing earthquake and the need for the Nigerian Government to be proactive by reducing the spate of substandard building construction.

Barely a year when Building Collapse Prevention Guild (BCPG) drew the attention of the world to the possibility of Nigeria experiencing earthquake and the need for the Nigerian government to be proactive by reducing the spate of substandard building construction across the nation, mild earthquakes, recently, occurred in parts of Oyo, Bayelsa, Rivers, and Kaduna states. Vibrations accompanying the earth tremors resulted in the collapse of mud houses and infliction of visible cracks in modern buildings within the affected areas. This development has clearly ossified the harbinger on the possibility of Nigeria having an earthquake induced disaster in the near future.

The perception that Nigeria is safe or far from seismic active regions is no longer tenable. Shaki in Oyo State has been subjected to intermittent earth tremors this year and climaxed in the first week of June,2016. Communities in Bayelsa and Rivers on July 10, 2016 had a similar experience but in this case due to prolonged effect of oil exploitation. Records from the seismological station of the Centre for Geodesy and Geodynamics (CGG) show that the earthquakes that occurred in Kwoi area of Kaduna State on 11th and 12th September, 2016 ranged from 2.8 to 3.1 in magnitude.

Shaki and Kwoi towns are not far from the Ifewara – Zungeru fault Zone, which is linked with the Atlantic fracture system. The fault transcends the South-West and North-West of the country, thereby making that stretch of land susceptible to seismicity due to stresses generated within the earth-crust, that is, partial reactivation of fossil plate boundaries.

Earth tremors occurred in Nigeria in 1933,1939,1964,1984,1990,1994,1997, 2000, 2009, 2011 and now 2016. A series of earth tremors might not necessarily lead to the high intensity earthquake, a reason that should douse our fears.

However, a study carried out by Dr. Adepelumi Adekunle Abraham of the Department of Geology, Obafemi Awolowo University, Ile- Ife and his team of researchers exacerbated the portentous signs in the following grim words, “After the earth tremor of 2009 in South- Western Nigeria, (which) was felt in several towns and villages in Oyo, Osun and Ogun States, a detailed short-term probabilistic earthquake prediction was carried out by our team, our findings indicated the probability of earthquake occurrence in the study area between the year 2009 and 2028 increased from 2.8% to 91.1%. The result also showed that the probability of three events occurring annually has the highest likelihood within the predicted years. Also, found that the Weibull probability density model predicts a damaging earthquake (Magnitude 5) before year 2020.”

Buildings are the bastion of physical development which is used to adjudge a nation’s rung in the global socio-economic ladder. Investors in buildings should be concerned about the durability of the buildings they are providing fund for. The longer a building exists, the more the revenue or value the owner derives from it. Indubitably, a solidly constructed building can stand the test of time.

The wise learns from the errors of others. Nigeria must not continue to repeat the mistake of Haiti and Nepal where stringent building regulations were lacking, thereby aggravating the effects of the earthquakes on buildings. In an earthquake disaster, the vulnerable, substandard buildings have always been the major cause of high death toll. And unfortunately in Nigeria, the National Building Code is legally and practically not in existence just as it was in Haiti.

A 5.7 magnitude earthquake occurred near Bukoba town in Northern Tanzania on September 10, 2016. According to local authorities, all fatalities were people ‘in brick structures’ that collapsed. Lesson from this experience is a warning to prospective homeowners and developers in Nigeria that they should endeavour to follow due process and avoid quakes. Government should pay due attention to building construction from the scratch by strengthening ministries of physical planning and development control, and also uphold the tenet of professionalism in the nation’s building industry.

The BCPG hereby reiterates the call by the Director of Centre for Geodesy and Geodynamics, in Toro, Bauchi State, Dr. Tahir Abubakar Yakubu that Nigerian government should establish additional seismological stations to monitor crustal movements in the identified earthquake prone areas, and the suggestions of Dr. Adepelumi Adekunle that Nigerian Government should invest in earthquake electromagnetic precursors monitoring devices that are capable of monitoring foreshocks, main shocks and aftershocks of any future earthquake event.

A nation without an effective national building code will end up in ruin in an occurrence of an earthquake. Enforcement of building regulations without compromise will prevent serious calamity in the future. Many nations, including USA, Japan and Australia have been constructing earthquake resistant buildings in their seismic regions. Nigeria can imitate such preventive measures. To be forewarned is to be forearmed.

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