Abigail did not set out to create and cause the witch trials, but she did not do anything to stop them once they began, either. In fact, she used her knowledge of human nature and her ability to read others to foster the trials in order to get rid of her competition for John Proctor--his wife, Elizabeth. Abigail also used her power over the other girls to force them to go along with her in the plan...this is the plan to cover up their activities in the woods as well as the fact that none of them see spirits or are inflicted by witches in any way.
Abigail did not cause the witchtrials; the naivete of some of the townspeople, mixed with some overreactions on the part of many who had suffered at the hands of their neighbors previously, are the real reason though for the trials. Their blend of religious beliefs and government made for an overly strict set of rules and consequences which many took advantage of, including Abigail.
The people's superstitious and legalistic religious beliefs caused the witch trials. Abigail understood the people's fears and took advantage of the opportunity to get revenge on John Proctor by accusing his wife of being a witch. When she visits Proctor to offer to help him escape, she more or less admits that her scheme has gotten out of control and that she never meant for it to go so far.
Was she the one to blame for the witch trials?