Truffles can grow at various depths within the soil, depending on a number of variables. These include the presence of tree large roots, soil texture, moisture levels, and nutrient availability. A truffle can be found just under the surface, over 10cm below, or even poking its crown out of the ground... Sometimes we see the earth cracking and being raised in an area where a truffle is pushing upwards from below as it grows and expands. We call this an "eruption".