Article 92
Generally such a charge is prosecuted under Article 92, UCMJ, as an orders violation. Each service has an order regarding relationships among the ranks.
What article of the UCMJ covers fraternization
Article 134
Article 92
Article 134
Article 86
134
It is a violation of Article 134 of the UCMJ.
86
108
Sexual harassment is not covered by a specific article of the UCMJ. DoD and each service, and even each command have published sexual harrassment policies. Violation of this policy could result in charges being brought under several articles of the UCMJ: Article 92 (Failure to obey an order or regulation), Article 128 (Assault) if any assault was involved in the violation, Article 134 (General Article) which can capture numerous violations including conduct unbecoming, adultry and other inappropriate behavior not covered by another article, Article 120 (Rape), and I'm sure there are others. These are just a few examples. Bottom line, sexual harrassment is a policy which is not directly covered by a UCMJ article when violated.
Article 86 of the Uniform Code of Military Justice (UCMJ) addresses failure to report or being absent without leave (AWOL).