A boy pulls a suitcase past debris in a flood-damaged area of Derna, eastern Libya. – AFP photo
VARIOUS views have been expressed by journalists in the international press on both issues in my title of this column, which concerns the earthquake in the High Atlas Mountains of Morocco on Sept 8 and a few days later the floodwaters from Wadi Derna on the east Libya Mediterranean coast.
More than 2,900 people were killed and 5,500 people injured in the shallow magnitude-6.8 temblor in Morrocco and its aftershocks. In Libya, locals now call Wadi Derna the ‘dam of death’ as officials estimate that as many as 20,000 people may have died.
2023 Moroccan Earthquake
Earthquakes are not uncommon in the High Atlas Mountains where huge fault lines run west to east through this region, for it is at the junction of the African and Eurasian Plates. The former plate is gradually moving northwards into the Mediterranean Sea at the rate of 2.5cm a year. Some of us will remember the 5.8 Richter scale quake at Agadir, which occurred to the southwest of the recent earthquake in 1960. Then 15,000 lives were lost. The more recent 2004 Moroccan earthquake saw the loss of 600 lives.
This 2023 quake struck in Al-Haouz province near the remote town of Ighil at 11pm that Friday and measured 6.8 on the Richter scale. The shallow depth of the quake at its epicentre some 18km below ground level, where an oblique thrust fault juddered, caused an upward force equivalent to the amount of energy released from 30 Hiroshima atomic bombs! A magnitude 4.9 shock wave occurred 19 minutes after the initial quake and other smaller aftershocks were recorded.
Effects of this earthquake
Marrakesh, a 12th century Unesco listed city, lies just 60km northwest of the epicentre with the loss of only 18 lives, saw parts of its medieval centre, the Medina, in ruins as buildings collapsed. Those buildings, like the ancient ones in the remote villages of the High Atlas affected by the quake, are not of modern designed earthquake resistant structures, and are mostly made of adobe (mud bricks). However, the 12th Kutubiyya Mosque in Marrakesh received only minor damage whilst another mosque was totally destroyed.
In the remoter mountain villages and smaller towns nearer to the quake’s epicentre the damage was more severe with the collapse of most single-storey houses and isolation imposed by massive landslides blocking very narrow, meandering access roads. Havoc has been created to the livelihoods of these remote people with the loss of apple production and livestock. Most of these people are Berbers and with their livelihood mostly based on agriculture; they were asleep when at 11pm that deadly earthquake occurred. It took many days for rescue teams with food and medical supplies to reach them.
A woman walks with her belongings through the rubble in the earthquake-damaged old city of Marrakech. – AFP photo
In a nutshell
According to seismologists, such happenings do not kill people for it is the very collapse of buildings that causes death. In this case it was inevitable that the death toll would be great as most families were asleep in their houses at that time of the night when the thunderous roar of the quake and shaking of their residences awoke them. Sadly, rescue teams from a multitude of countries are recovering buried corpses as the death toll still rises.
Eastern Libya’s Derna flood disaster – the scenario
In the early hours of Monday, Sept 11, the coastal city of Derna was devastated by a massive flood occasioned by the bursting and destruction of two dams containing reservoirs on the Wadi Derna. Normally the annual rainfall is relatively little but on the previous day 80 per cent of that city’s annual average rainfall total descended from the heavens!
Earlier, in the previous week, Storm Daniel caused massive flooding in Greece, Turkey, and Bulgaria. This storm then swirled over Derna dumping 414mm of rain in a very short time as it quickly passed overhead.
With mountains as a backdrop to this deltaic city and ground parched and impregnable by the summer heat, the runoff from the higher land moved swiftly along Wadi Derna. Wadis are normally dry riverbeds but are susceptible to flash floods on infrequent occasions. Along the course of this wadi, two dams had been constructed in the 1970s to conserve water, irrigate crops, and provide fresh water to Derna city. On that momentous day, the smaller Al-Bilad dam upriver collapsed allowing the floodwaters to reach the lower and larger Abu Mansour dam, causing it also to fail. The upper dam had the capacity to hold 1.5 million cubic metres of water and the lower dam 22.5 million cubic metres.
Both dams experienced considerable damage caused by a storm in 1986 and cracks were reported in 1998. Only a year ago, a researcher at the nearby university of Bayda warned of the urgent repair of these dams as there was ‘a high potential for flood risk’ should these dams collapse. How true his prophecy was for the sheer volume of water rushing down the wadi, combined with the unstable condition of the dams, produced seven-metre-high waves of flood water to overcome Derna city.
Impact of this storm on Derna
Six square kilometres of this city’s land was inundated with 24 per cent of its buildings suffering damage. Of these structures, 59 per cent were completely destroyed and the rest partially destroyed or submerged in mud. People were swept away from the flood waters and washed out into the Mediterranean Sea. It is thought that the final death toll was around 20,000 out of the city’s total population of 100,000, with nearly 50 per cent of the survivors displaced. A very sad thought for this war-torn country.
The verdict
Whilst Storm Daniel caused extensive flooding in Greece, Turkey, and Bulgaria, it was its development into an almost tropical cyclone that caused the intensive rainfall input as it moved from the Mediterranean Sea over the Libyan coastline. The dams did need to be repaired and, had adequate warning systems been in place, could have gradually released some of their reservoir water through their floodgates. People, then, could have taken adequate steps to move to safer ground and refuge centres.
With both disasters, it is easy to point the finger at governments both local and national but ultimately it is nigh impossible to predict the likely epicentre of an earthquake or the actual input of rain from a severe storm. In future, however, we can be better prepared by ensuring that new housing developments have earthquake resistant structures, as in Japan, and that property developers do not build new housing estates on river flood plains.
Do remember that in the two scenarios I have tried to explain that both places affected by these tragedies are of ancient origin. The war against the outcome of natural disasters does not stop for the survivors in both areas as there is still a risk of cholera, diarrhoea, and malnutrition as clean water, food, and medical supplies are in short supply.
Should you feel that you may want to help the victims of these disasters, then please donate to the International Red Cross and Red Crescent Disaster Fund.