The foundation has been unstable. No one can guarantee that a piece of land will not fall for a thousand years. According to plate tectonics, even the present surface is formed by plate movement. Therefore, I think this kind of giant pit may be formed by a small range of plate movements. I'm thinking, every day in a piece of land, people step on the car and get wet, and dogs shit on their heads. Over time, the property had some emotional fluctuations, which exceeded its psychological endurance, so it collapsed on its own (just like jumping off a building when people didn't want to live). Is this a great possibility?
2. The soil is very loose.
Soil osteoporosis is just like osteoporosis. It is easy to understand that when people get old, bones are not as dense as before. I am a big country and has been tested for many years. It is normal for several small places to collapse. As long as the building does not fall down and there are not many casualties, it is still reasonable. However, when people get older, they have to supplement calcium and cultivate backbone to live longer. Otherwise, when the heart is willing but unable, I'm afraid it's too late to regret.
3. Cold and heat disorders
My understanding is that it expands with heat and contracts with cold. Now that the temperature is rising, the surface temperature is obviously higher than that of the lower soil, so the surface is self-expanding and self-confident, forgetting that there is still deep soil under your feet. At this time, the lower soil disagreed and felt that the lower place was too cold, so it shrank back by itself. I don't think I can ride on my head for a few days. Due to the disharmony between the upper and lower soils, it collapsed.
4. Overexploitation
Excuse me, can you stand someone holding a shovel all day to cut off your head? I don't think you can stand it. I can't stand it anyway. Isn't the land the same? Originally, there was not much wealth on the land, but now people use shovels to collect and hand it over every day. Which piece of land can stand it? Some land can't stand it. If you dig it elsewhere, it will collapse. Why? Because this land is closely connected with that land. As the saying goes, the lips die and the teeth are cold. Who's not afraid?
In fact, the collapse of several plots of land is a trivial matter. But I am a person with rich associations.
Have you noticed that officials are in a panic, employees fall downstairs and their conscience is in a black hole?
I think what is more terrible than the huge pit of land is the huge pit of society; More serious than land collapse is the loss of conscience and justice.