California's still shaking all over

SHAKE, rattle and roll: earthquakes are a way of life in California.
The small ones, like the mini-quake that happened last week, seldom do much
damage, but they can easily disrupt otherwise stable slopes. These boulders,
which are the size of a small car, have tumbled from a road cutting on the
slopes of Mount Baldy in southern California. A more insidious danger is
liquefaction of soils, making ground which was once stable become treacherously
fluid.