Why is so much archaeology buried? Well there are two main ways in which this happens. The first is the natural process of deposition. Basically, natural forces like wind, weather and erosion can cause layers of dust, silt or earth to form on top of an abandoned site. A good example is a site at the bottom of a large hill - over time, natural forces will erode the soil, causing it to slip down the hill and possibly burying the site at the bottom. This process can take hundreds of years, or it may take a few hours - the eruption of the volcano which buried the Roman town of Pompeii in ash is another example of natural deposition.
The process of deposition is very important to archaeologists. We use the different layers of earth we find to try and work out when things happened, and also to work out what things on a site were around at the same time, and we call these layers deposits.
The other main way in which the past can be buried is through human action. This may be as simple as someone demolishing a building and then building on top of it, burying a rubbish pit, or disposing of their dead., or there may be a more complicated reason for deliberately burying something, perhaps to keep it safe or as an offering to the gods.