I thought it could be an advanced form of ring shake. But when I looked it up it’s known as cup shake
Edit
But see if you can work this definition of it out ?
- Cup and/or Ring Shakes: Cup shakes follow the annual growth ring. It is capable to separate the growth ring partially or completely. When the crack separates the annual ring completely, it is called ring shakes. So, all ring shakes are cup shakes, but all cup shakes are not a ring shape. Excessive frost action is the main reason for this type of crack.