Furore over recent Earth tremors in Abuja

The earth tremor that lasted for three days in Mpape and some parts of Maitama district in Federal Capital Territory (FCT) left not only residents, but also the whole country apprehensive that an earthquake was about to occur.

The residents of the affected were alarmed by the sudden shake of the earth, which started on Thursday, September 5 to 8, as they were seen relocating to other places in the city with fear of losing their lives to such incident.

Many feared that the January 12 earthquake in Haiti was about to occur in those parts of Nigeria.

The effect of the 7.3 magnitude earthquake in 2010 that killed no fewer than 230,000, leaving 300,000 injured and displacing more that 600,000 in Port-au-Prince, Haiti’s capital, still lingers in the minds of people around the world.

This development left many Nigerians reacting, with some calling on God for help.

Also, the Senate President, Dr. Bukola Saraki, Chairman of the Senate Committee on FCT, Senator Dino Melaye and former vice president of Nigeria and current presidential aspirant, Atiku Abubakar among other government officials expressed concern towards the incident, while instructing emergency services to check the causes and be on high alert to prevent the loss of lives and property.

Nigerian scientists at the National Space Research and Development Agency (NARSDA) had warned that Nigeria should be prepared for earthquake experience, which should set the authorities thinking and planning now.

The predicted date of 20 years from 2008 of an earthquake occurrence in Nigeria is not far, as signs have started emerging through the Abuja earth tremor.

Although, the Emergency Management Agency of Nigeria’s Federal capital territory, Abuja, confirmed the reports of the earth tremor in the affected areas, it suggested it could have come from the movement of the earth or that it could be by the blasting of rocks or mining in the area, while it urged residents to stay calm and hide under tables if inside the house or stay away from buildings if outdoor.

Similarly, in a recent publication in a learned journal, at exactly 3:10 GMT on September 11, 2009, an earth tremor occurred in the Abeokuta environs, Ogun State. The earthquake was felt mainly in most parts of the state and some parts of Lagos State.

Three seismic stations of the Centre for Geodynamics and Geodesy (CGG) network in Nigeria recorded this event and since 2008 when CGG network started, September 11 event was the first major tremor recorded instrumentally. Although there have been many earth tremors (minor to major) in the past in this part of the country and other areas but there have not been local instrumental records to analyse the seismicity (vulnerability to earthquakes) of the region.

The NARSDA researchers said the tremor is a sign that Nigeria is not immune from earthquake occurrence.

One of the researchers from the Geology Department of Obafemi Awolowo University (OAU), Ile Ife, Osun State, Dr. Abraham Adekunle Adepetumi told The Guardian that the country is not in the earthquake-safe region.

Predicting long-term earthquake possibility, he said: “The Empirical Earthquake Recurrence Model – a time-dependent model – was employed to predict the probabilistic occurrences of earthquakes in the Ijebu-Ode and environs between the year 2008 and 2028.

Meanwhile the Director General, NASRDA, Prof. Seidu Mohammed in a statement made available to The Guardian said that the preliminary investigations by the agency on the earth tremors experienced in Abuja has revealed the incident as minor and below 3.0 magnitudes.

Mohammed made the statement on Tuesday, September 11 in Abuja during a press briefing held at Obasanjo Space Centre on the formal presentation of technical report on the incidents by the Space Agency, which has as part of its mandates earth observation research as well as monitoring and prediction of Geo hazards using Space Geodetic and Geophysical Techniques.

According to investigations carried out by experts in the Space Agency, “the main earthquake occurred on Friday September 7 at 5:11:32 am with a moment magnitude of 2.6 and a local magnitude of 3.0, while the foreshocks and aftershocks were experienced on Wednesday and Thursday, as well as Friday and Saturday respectively. The foreshock and aftershocks all had a magnitude of less than 3.0.”

Professor Mohammed explained that the stress dropped from the main earthquake was 2.1 bar, and the length of fault displacement was computed as 0.56kilometer, while the rupture or focal depth of the earthquake was estimated between 10kilometer and 15kilometer.

He pointed out that although, it is difficult to predict earth tremors and earthquakes, however, certain parameters can be put in place to monitor the activities of crustal movement within the fault lines of the country so as to understand the trend of such movements.

Meanwhile, experts and researchers from Kujama seismic station in Kaduna state, which is closest to the scene of the incidence visited the area where the vibrations were felt and estimated the intensities of the earthquakes in Jahi and parts of Gwarinpa as II –III on the Modifies Marcelli Scale (MMS), and in Katampe area it was III while in Mpape it was estimated as III – IV with the strongest shakings observed around Ajegunle in Mpape.

The NASRDA team which comprised of experts from its Centre for Geodesy and Geodynamics in Toro visited the site of the incidents on physical investigations so as to determine the vulnerability of structures in the affected areas in order to mitigate future disasters.

The Director of Centre for Geodesy and Geodynamics, an activity centre of the Space Agency located in Toro Bauchi state, Dr Tahir Yakubu said further investigations are on-going to understand the contributory cause to the recent incident.

He said apart from the area being located along the epicentre, certain activities such as rock blasting and other earth moving activities along these fault lines could trigger movement in the earth that may lead to such incidents.

Dr Yakubu also observed that rain water can become a lubricant that can make for easy crustal movement along these fault lines.

He therefore called for caution during such activities, saying, construction of infrastructure such as rail lines along these fault lines should be done with an understanding of the nature and peculiarity of the area.

According to him, further investigations will also be conducted to establish a link between the Kwoi incident in Kaduna which occurred in September 2016 and the recent occurrence in Abuja on to reveal and understand causal factors and deduce similarities between both occurrences.

Dr Yakubu explained that details of the various investigations by the Space Agency would be made available to relevant authorities for holistic and strategic planning in the wider area of Mpape and the Federal Capital Territory as a whole.

The centre Director therefore called on the Federal Government to assist in the establishment of more seismic stations across the nation in line with global practice for effective monitoring and collation of relevant data of seismic activities in the country.

In response to prevent such occurrence, the Minister of the Federal Capital Territory (FCT), Malam Muhammad Musa Bello has suspended quarrying, mining and borehole drilling in Mpape, Gwarimpa and Garki, which he said could be the cause of the tremor, while assuring residents that there was no cause for alarm, noting that geologists have said that Abuja was not on the line of any major seismic danger.

Also, the director general of the Nigerian Geological Survey Agency (NGSA), Alex Ndubuisi Nwegbu urged residents not to panic, “as the situation is not yet out of control.”

He said the federal government has recently procured six earth quake monitoring seismograms to enable proper monitoring of all ground disturbances, though they are yet to be fully installed in six geographical zones in the country.

He, however, said an analysis of the regional geophysical data has identified the area to undergo series of tectonic activities leading to structural emplacement.

While describing an earth quake as a sudden vibration, sometimes violent, of the earth’s surface that follows a release of elastic energy in the earth’s crust, he said this energy is generated by a sudden dislocation of the crust when the built up stress exceeds the strength of the rock mass.