Geology
Mission Peak is the site of a large (300 m wide by 1200 m long) landslide that started in March, 1998 due to the El Niño rains that winter. The landslide occurred in an area that had seen previous landslides in the past. The landslide threatened new housing and has changed local development regulations to deal with geotechnical hazards.
Some sources have labeled Mission Peak as an extinct volcano due to its shape and the sharp point of the peak. This, however, is simply the result of natural uplift and erosion though; the peak has no volcanic origin. This range of the hills is being compressed due to the proximity of the Hayward Fault to the west and the Calaveras Fault to the east, which has led to a number of smaller faults and uplift.
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