Questions about a recently purchased wok
I don't think those are "cracked ridges"; I think you have a hammered wok.  The appearance is an artifact of how they are manufacted, by hammering a steel blank into a form or mold.   It probably is a carbon steel wok, as that is the most common material used for the hammering method as far as I know.   

According to this article at The Kitchn, you should season it as follows:


  
  Scrub your wok in hot, soapy water and then dry it over low heat on the stove.
  Turn the burner on your stove to HIGH and add 2 to 3 tablespoons of oil to the wok. I prefer peanut oil, but any oil can be used - sesame,
  chili, or canola. Coat the wok surface evenly with oil by tilting and
  turning it.
  Heat the oil and keep the oil spread across the surface until it starts to "glaze" the wok - in other words, it turns into a thin layer
  of film. Use a wok spatula to move the oil around and tilt/turn the
  wok to move the oil as well. Be careful not to spill any oil that
  would start a grease fire!
  Let the wok cool and the layer of oil will harden on the surface.