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Monday, 18 September 2023 06:07

[OPINION] Earthquakes, floods: Act of God or act of carelessness? - Bolanle Bolawole

The earthquake in Morocco, which killed thousands and left many more homeless, led me to ask questions. About the same time, floods in neighbouring Libya also reportedly killed its own thousands, leaving many more homeless. In both cases, millions of people; nay, entire countries and humanity as a whole, have been left traumatised. What if any of these shoes were on our own foot or did we think, as we are wont to, that it can never happen here? The answers that I got to the questions that I asked told me pointedly that we will be wrong to think so.

  1. Has Africa ever experienced an earthquake? “The Horn of Africa has significant seismic hazard associated with the East African rift system. A number of destructive earthquakes, some deadly, have been reported this century. Notable events include the 1921 earthquake that destroyed the port city of Massawa in Eritrea”.
  2. What was the biggest earthquake in Africa? “The two largest instrumentally-recorded events in Africa occurred ¬ 300 km north of Lake Albert (250-65 Ma) rifting. These M 7.1 earthquakes struck four days apart in May 1990, both at ¬15 km apart; their tectonic relationship to the Albert rift system or Mesozoic faults remains unclear”
  3. Why is Africa generally not affected by earthquakes? “Most of the Continent consists of stable Cratons which are far from the tectonic boundaries under the Oceans, to the west, south and east; so there is little activity”
  4. Is Nigeria prone to earthquakes? “For about 10 decades, the seismic record of Nigeria has shown the occurrence of several magnitudes of earthquakes. This is contrary to the belief of some people in time past that Nigeria is a-seismic (that is, not prone to the occurrence of earthquakes). In number and in size, most of the earthquakes witnessed in Nigeria were found to have occurred in her South-west region”
  5. Where was the first earthquake in Africa? “The oldest recorded earthquake was in South Africa, and was widely accepted to have occurred on 7th April, 1620”
  6. Where are 90% of earthquakes? “The ‘Ring of Fire’, also called the Circum-Pacific belt, is the zone of earthquakes surrounding the Pacific Ocean; about 90% of the world’s earthquakes occur here”
  7. Which country in Africa is prone to earthquakes? “Southern Africa, which has already had large- and small-scale magnitude earthquakes. This region encompasses Zimbabwe, Mozambique, Zambia, Angola, Namibia, and South Africa”
  8. Has there been a tsunami in Africa? “A total of three tidal waves classified as a tsunami have, since 1969, killed three people in South Africa. Tsunamis, therefore, occur only rarely here. The strongest tidal wave registered in South Africa so far, on 27 August, 1969, reached a height of 2.9 metres but no human loss was registered.
  9. Where are earthquakes most common in Africa? “The majority of seismic activity is concentrated along the East African Rift System, with additional active regions along stretches of the continental margins in north and east Africa, and in the Congo Basin”
  10. Does Africa have volcanoes? ”Less well known is the fact that Africa is home to more than 100 volcanoes that have been active during Holocene time (roughly the past 10,000 years), including one of the most voluminous and dangerous lava lakes on Earth, and to a rift system that is actively splitting the continent apart”
  11. What are the worst countries for earthquakes? “Japan, located in the Pacific ‘Ring of Fire’, tops the list of the world’s most seismically active countries with an average of more than 1500 earthquakes of magnitude 4 and above occurring in the country annually”
  12. Which country cannot experience earthquakes? ”Antarctica has the least earthquakes of any continent but small earthquakes can occur anywhere in the world”
  13. Did earthquakes ever happen in Nigeria? “The first earthquake in Nigeria occurred in 1939 in Ibadan while the first tremor was recorded in Warri in 1933. Many other earthquakes have occurred after these”
  14. When was the last time that earthquakes happened in Nigeria? “The last officially reported episode was on November 1, 2018. An earlier event on September 5, 2018 that lasted for three days in Mpape and some parts of Maitama district of the Federal Capital Territory had left (people) apprehensive that an earthquake was about to occur”
  15. What seismic zone is Nigeria in? “Nigeria is located in Zone 1, capable of the order of earthquake magnitude 6.0 – 6.5, modified after International Geoscience Group (IGCP).”
  16. What is the largest earthquake ever recorded? “The Valdivia Earthquake occurred on May 22, 1960. It was the most powerful earthquake in recorded history, with a magnitude of 9.5. It struck southern Chile. Valdivia left two million people homeless, injured at least 3000 and killed about 155 people. It triggered a massive tsunami that raced across the Pacific.
  17. When was the longest earthquake event? “A devastating earthquake in Indonesia in 1861 was the crescendo of a 32-year-long clash between the tectonic plates below the island.”
  18. Where is the strongest earthquake ever? The biggest earthquake ever recorded, of magnitude 9.5, happened in Chile, at a subduction zone where the Pacific plate dives under the South American plate”
  19. Where is the strongest earthquake? “The world’s largest earthquake with an instrumentally-documented magnitude occurred on May 22, 1960 near Valdivia in southern Chile. It was assigned a magnitude of 9.5 by the United Geological Survey. It is referred to as the ‘Great Chilean Earthquake’ or the ‘1960 Valdivia Earthquake’ The United States Geological Survey reports this event as the ‘largest earthquake of the 20th Century’ Other earthquakes in recorded history may have been larger; however, this is the largest earthquake that has occurred since accurate estimates of magnitude became possible in the early 1900s.”
  20. Where is the “Ring of Fire”? “The ‘Ring of Fire’ is not quite a circular ring (but) is shaped more like a 40,000-kilometre (25,000-mile) horse shoe. A string of 52 volcanoes stretches from the southern tip of South America, up along the coast of North America, across the Bering Strait, down through Japan and into New Zealand.”
  21. Which African country has the most natural disasters? “Mozambique presented the highest natural disaster risk in Africa as of 2022. The country scored 34.37 in the WoldRiskIndex assessment and ranked among the 10 nations in the world under very high risk of being confronted with disasters due to extreme natural events”
  22. Is Africa splitting in two? “The East African Rift System (EARS) runs downward through Ethiopia, Kenya, the Democratic Republic of Congo, Uganda, Rwanda, Burundi, Zambia, Tanzania, Malawi and Mozambique. Africa is slowly but surely splitting in two. The east of the continent is scarred by one of the largest rifts in the world.”
  23. Why do earthquakes occur in Africa? “Hot magma rises from the mantle at mid-ocean ridges, pushing the plates apart. Earthquakes occur along the fractures that appear as the plates move apart.”
  24. Where is the safest place to be during an earthquake? “An interior room of your house without any windows, such as a bathroom. If possible, take cover inside something sturdy, like a heavy table, desk or doorway.”
  25. Can you hear an earthquake coming? “Small shallow earthquakes sometimes produce rumbling sounds or booms that can be heard by people who are very close to them. High-frequency vibrations from the shallow earthquake generate the booming sound; when earthquakes are deeper, those vibrations never reach the surface.
  26. How long does an earthquake last? “Generally, only seconds! Strong ground-shaking during a moderate earthquake typically lasts about 10 to 30 seconds! Readjustments in the earth cause more earthquakes (aftershocks) that can occur intermittently for weeks and months.”
  27. Can someone or something trigger an earthquake? “Injecting fluid underground can induce earthquakes, a fact that was established decades ago by USGS scientists. This process increases the fluid pressure within fault zones, making them more likely to fail in an earthquake”
  28. Can earthquakes be prevented? “We cannot prevent natural earthquakes from occurring but we can significantly mitigate their effects by identifying hazards, building safer structures, and providing education on earthquake safety. By preparing for natural earthquakes we can also reduce the risk from human-induced earthquakes”.
  29. How long can a human survive in an earthquake? “Generally-speaking, people trapped in the rubble of an earthquake can only survive about a week. Experts say that, typically, it is rare to find survivors after the fifth to seventh days and that most search-and-rescue teams will consider stopping by then” Finally, which countries have suffered most from earthquakes? “Japan, located in the Pacific ‘Ring of Fire’, tops the list of the world’s most seismically active countries, with an average of more than 1500 earthquakes of magnitude 4 and above occurring in the country annually. The others are Indonesia, China, Philippines, Iran, Turkey, Peru, USA, Italy, Mexico and New Zealand. Interestingly, countries with the most fatalities from earthquakes are Indonesia (227, 898), Haiti (160,000), China (87, 587) and Pakistan (87, 351). The Morocco earthquake has claimed close to 3000 deaths as at press time.

From the above statistics we can deduce the following: Africa in general and Nigeria in particular are fortunate that we are not in seismically-active zones but this is not to foreclose the occurrence of devastating earthquakes here. Morocco is an example and eye-opener. South-west Nigeria must also watch it. As our people would say: “It is coming, it is coming”; you don’t wait until it comes before you act but must prepare your net to catch it when eventually it arrives. Are we prepared? Are we even mindful of the fact that we must prepare for any eventualities? What body of knowledge do we have, both as a people and as a government, on this occurrence? Building safer structures, providing education and preparing for any eventualities are sine qua non if we are not to be caught pants down. If earthquakes are generally an act of God, floods are mixtures of both. Human activities have depleted the ozone layer, causing the temperature of the Earth to rise astronomically, the melting of the ice sheet, a rise in the sea levels and floods never before experienced. Efforts to control this man-made disaster, which is already creeping in on us before our very eyes, have floundered on the altar of the selfish interest of the superpower nations. On the home front, in Lagos especially, we sand-fill and reclaim land; we convert wetlands to housing estates and business districts; we build on drainages and obstruct the flow of the body of waters. Waste disposal architecture of the State government is not working; most drainage is blocked by indiscriminate disposal of refuse and the lethargy of the relevant authorities has not helped matters.

No one fights water and wins. No one disrespects or distracts it without paying a price for it. Water fights silently; but it also fights viciously. If we wait to behold its rage in forms and tempo worse than the samples and warning signals it has been giving us, then, we will have only ourselves to blame. If we are wise, we will urgently and earnestly learn from the Morocco and Libya disasters.

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