Dramatic and scary earth fissures unrelated to earthquakes are rather common around the world, especially in arid areas. Where the surface material is void of vegetation and organic matter but contains some clay, dry conditions may result in fissures (similar to how mud cracks). This surface cracking can be extensive and deep when associated with subsidence.
In this desert environment, it occurs in response to groundwater pumping. Pulling out huge volumes of water from unconsolidated sediments (such as sand aquifers) results in compaction, which translates on the surface as wide-scale sinking and visible fractures or tension cracks.
To those not familiar with ground fissures due to subsidence or extraction, the appearance of these huge cracks in the earth is mysterious and alarming. The latest ground fissuring incident making the rounds on “Apocalyptic” and “earth changes” websites is in the Tamir province of central Saudi Arabia north of Riyadh. The phenomenon was filmed and uploaded to YouTube by several people.
This video shows the deep fissure in loose, clayey sand. The walls easily collapse further when disturbed. The information provided roughly translates to say that the crack divides the populated area, terrifying some of the inhabitants, who are demanding the “rare” event be studied.
A February 28, 2018 video titled “Deep ground cracks north of Riyadh today” showed the location as near the village of Al Majma’ah northwest of Riyadh. The description also noted that the phenomenon was “strange” and the opening extended approximately 28 km. Local officials were looking into the events.
Although translating and searching in Arabic is difficult, there was a suggestion that the cracks became large and noticeable after a recent rain event. In the videos, you can see darker areas that appear moist suggesting that the rain widened a smaller fracture. A check of the weather at the airport in Riyadh showed a thunderstorm passed through on February 24 with rain into the early morning of the next day. No other rain was noted in February.
Such ground fracturing is not, in fact, “rare” in Saudi Arabia and it has been studied before. These studies show that fractures are linked to the amount of groundwater extracted by human settlements. It could be that the locals have not had these fractures appear in this area but that the aquifer is being depleted locally or even from miles away. A study of the local aquifer in Riyadh (Al-Jallal, I.A., 1979, “Hydrogeology of the Minjur Aquifer in the Riyadh Region of Saudi Arabia”) described additional well fields for public and private uses were being installed in the late 1970’s but that the sandstone aquifer was exploited in the area since the mid-1950s. Riyadh is the capital of the country, with a population of more than 6 million people.
Exploitation of wells producing from the Minjur Sandstone beneath Riyadh was begun in 1956, when the first well was drilled. Since then the number of wells has increased as has the production. Production started with 35 l/sec in 1956-57 from the Shumaisi Well and was increased gradually to a total of 45 l/sec for two wells. In 1958, the production was 105 l/sec, over 600 l/sec in 1967 and more than 900 l/sec in 1971. There is almost a yearly increase in water requirements by people in the city as a result of the increase in the rate of growth. The production increased as the number of productive wells increased.
Such growth could not be sustained in the slowly-recharged aquifers and much of the water (~50%) now comes from desalination of Persian Gulf waters. The people overused water for wasteful agriculture practices and high general consumption. A serious shortage of water is projected for the coming decades.
The sensible conclusion is that these fissures were the result of groundwater depletion. While the locals may not have noticed them before, the situation suggests they should get used to seeing them appear. It might be a frightening future indeed if technology can’t solve the problem of providing available water to central Saudi Arabia. The earth has given all it can.