How do I populate a field with a portion of another field

[jd2980]

I would like to take the "JVD" from 40430_Huber_JVD_1244_DiSalvo,E.doc which is a record in table Reports and save it to another field Author aslo in table reports. Each audhor will be be after the second "_" currently I run an update query looking for "*_JVD_*" and update the author field with "JVD" for each author I need to write a seperate Query. I update about 10k records per month and each time I get a new author I need to create a new update query. Curently I have about 125 update querys. There has to be a better way...HELP