File:CalMemStadFaultCreep.jpg

Major sections of California Memorial Stadium have been offset due to aseismic creep of the Hayward Fault. Image by User:Leonard G.

The sections are offset here (on the south end of the stadium) about 1/6 m here (6-7 inches), with the total fault creep estimated at 13 inches since the construction of the stadium 84 years previous to this image. The footings for the supports have not offset, causing the divergence of the columns to appear only at the top, but more visible than otherwise owing to the angle between them.

These columns support corresponding ends of stadium seating sections at mid-points, which act as rigid plates. The section to the right is fixed in the foot of the Berkeley hills, while the sections to the left are moving away from the viewpoint and several sections are also rotating clockwise as the extreme left edge is moving north with the alluvial plain extending to San Francisco Bay.

In the event of a major fault movement the displacement here could be as much as six feet, with tearing and shaking resulting in the dismantling of the structure. Seismic retrofit modifications are being performed (Fall 2011 through Summer 2014) as part of a major upgrade to the stadium, this involving rebuilding portions upon floating mats (foundations that do not penetrate the surface, rather sitting upon plastic sheets over level graded sand) where they pass over and near the fault, with appropriate sliding connections for the safety of spectators.