The Lawson Adit is a horizontal mine tunnel, or adit, on the UC Berkeley campus, near the Hearst Mining Building, dug directly through the Hayward Fault.[1] It is named after Andrew Lawson, one-time Dean of the College of Mining at UC Berkeley.[2]
The adit was originally around 200 feet long, and was dug to provide hands-on training for mining and metallurgy students, with secondary hopes that it would represent a new source of water for the campus.[1][3] Around 1939 the adit was extended to around 900 feet so that it intersected the Hayward Fault and could be used to directly study it,[1] but much of the extended adit later collapsed and today it is only maintained to about 260 feet.[1][3] Most of the collapses have been around the point where the adit intersects the fault.
Between 1919 and 1930 the adit was used to give mining and metallurgy students hands-on training, specifically to provide "sound, practical training in drilling, drifting, blasting, timbering, and mine surveying."[3][1] This training included instruction in the use of dynamite as well as the extraction of precious metals[1] and practice and demonstration of rescuing techniques.[4] Much of the equipment to dig and use the tunnel was donated by the mining industry.[3]
Starting around 1939, the tunnel was extended so that George Louderback, a seismologist at UC Berkeley, could study the Hayward Fault to determine the safety of building a new women's dormitory, Stern Hall. The results of his investigation led him to suggest that Stern Hall be built approximately fifty feet away from its original planned location.[1][3]
Louderback's studies in the adit revealed that the Hayward Fault at this point is surrounded by a particularly unstable mélange of serpentine and other metamorphic rocks.[5]