The region is lace with faults, many running out into the sea from the
mainland, others on the islands themselves. These faults are places where the earth is experiencing tremendous conflicting forces as the surface plates are forced in opposite directions, at times colliding, at other times slipping past each other. The disastrous earthquakes of California are well known world wide, and have resulted in devastating freeway collapses, fires that have swept through entire cities, tidal waves, buildings slipping into the sea, and loss of life and buildings on a massive scale. They are also the reason an entire native island population moved from the Channel to the mainland Santa Barbara Mission in 1812.
The force of the Pacific tectonic plate moving into the mainland of
western American is a force we can not control or stop. What can be done is live in preparation for earthquakes, and to support scientists who are developing earthquake detection methods for early warnings.