One may intentionally push from conscious awareness into unconsciousness traumatic and emotionally laden experiences. the explanation for the inability to recall that experience is known as

The explanation is known as: Repression Theory. 
Repression Theory. was popularized by Sigmund  Freud. According to this theory, the unconcious mind could play an important role in determining which type of memory that we could remember. If a certain memory somehow mentally shook the individual, the unconscious mind would repress the memory as a form of coping mechanism.