In 1988, Webb was recruited by the "San Jose Mercury News", which was looking for an investigative reporter. He was assigned to its Sacramento bureau, where he was allowed to choose most of his own stories. As part of "The Mercury News" team that covered the 1989 Loma Prieta earthquake, Webb and his colleague Pete Carey wrote a story examining the reasons for the collapse of the Cypress Street Viaduct. "The Mercury News" coverage of the earthquake won its staff the Pulitzer Prize for General News Reporting in 1990.