California Memorial Stadium ("CMS") sits directly over an earthquake fault (the Hayward Fault). CMS was built in 1923. It was seriously in need of seismic strengthening if Cal was going to continue using it. The east side of the stadium is built into the earth, but the west side is not, and could have been a real danger if an earthquake of significant strength occurred. Building a new stadium in Berkeley was not a viable option. Land acquisition costs alone would have been prohibitive.
The University's decision to retrofit CMS was in no way Sandy Barbour's decision. That decision was made well above her pay grade, and reflected a conclusion by the U.C. administration that the liability risk of doing nothing was just too great.