Search teams have moved on to fields close to the university
A friend of the family of missing chef Claudia Lawrence says the latest police searches are "very encouraging".
Officers have been searching an area known as The Outgang in Heslington, York, since Tuesday and expect the operation to continue until Friday.
North Yorkshire Police said the search was the result of information received "in the last few days".
Martin Dales said: "It's amazing after a year this information seems to have only just come out."
Miss Lawrence, who was 35 when she went missing, was last seen leaving work at the University of York's Goodricke College on 18 March 2009.
Mr Dales, a friend of Miss Lawrence's father Peter, said: "It's obviously very encouraging that the police are still physically searching as well as doing all the work they're doing in the backroom on the computers and interviewing people."
Mr Lawrence has campaigned regularly for help to find his daughter.
Mr Dales said: "All the time we're out there doing this the information is coming into the police so it makes what you're doing worthwhile, albeit incredibly hard to actually do particularly for Peter as Claudia's father.
Claudia Lawrence has not been seen since March 2009
"We had quite a lot of false hopes raised by searches and information, but it's all the information coming in that helps police to build up a picture and it could be one thing that somebody out there knows that could resolve this for everybody."
Land near to a children's play area, accessed by a muddy farm track, was searched on Wednesday.
On Thursday officers moved on to a field close to the university.
Police said no digging was taking place at the field, which is bordered by student accommodation and a playing field.
The searches are not connected to an appeal earlier this month in which detectives said they wanted to speak to a "mystery boyfriend" Miss Lawrence spent the night with two nights before she vanished.
The investigation is one of the largest ever carried out by North Yorkshire Police.
Miss Lawrence's disappearance is being treated as suspected murder.