Officers were called shortly after 2.50am to reports that an 18-year-old woman was raped by a man who she is believed to have met earlier on that night close to Broad Oak Woods in Carrington.
The man is thought to be aged between 20 and 25 and is described as a white man with a Salford accent.
He is believed to be around 5ft 7/8ins tall with a medium build and wearing what appeared to be a grey tracksuit.
He has dark blonde hair; short at the sides and with a longer fringe to one side.
No arrests have been made and specialist officers are supporting her at this time.
Earlier that evening, an 18-year-old man was seriously assaulted and responding officers administered life-saving first aid at the scene before paramedics arrived.
The man remains in hospital in a serious but stable condition.
Two other men – aged 25 and 26 – were also injured in separate attacks and have since been discharged from hospital.
An 18-year-old man has been arrested on suspicion of section 18 assault and is in custody to be questioned by detectives.
Police are also aware and are investigating a video on social media purporting to show three men and a woman wielding large bladed weapons close to the area where the rave is said to have taken place.
Anyone who may have witnessed any of incidents, or have information in relation to them, is asked to contact the police or Crimestoppers to aid detectives’ enquiries.
Investigators are keen to stress that their focus is on the attacks that took place and no retrospective action will be taken against those at the rave who provide information.
Detective Inspector Julian Scarsbrook, of GMP’s Trafford division, said: “This is an urgent appeal for information relating to the horrific rape of a woman and three vicious assaults – one of which almost cost a young man his life.
“While I – like the majority of the public – was shocked and dismayed at the scenes in Carrington on Saturday night, my interest is entirely focussed on investigating the serious crimes that took place that evening.
“I understand some people may be reluctant to contact police because they were present at the rave on Saturday and don’t want to land themselves in trouble, but I must stress that the severity of these crimes outweigh any self-interests people may possess.
“No one should feel deterred from providing the police or Crimestoppers with any information that they believe could have the slightest bit of relevance into finding those responsible for these assaults.
“If you saw anyone in possession of a potential weapon or noticed certain hostilities between groups that night, it is vitally important that you get in touch and provide us with as much information as possible.
“Information will be treated with the strictest confidence and I urge any witnesses or those with details that could aid our enquiries to do the right thing and contact us directly, or anonymously through Crimestoppers.”
Anyone with any information should call police on 0161 856 7573 quoting Operation Norfolk. Details can also be passed anonymously to the independent charity Crimestoppers on 0800 555 111.
Video footage can be uploaded via the following link: SCD.CCTV@GMP.POLICE.UK