Hi Cathryn. That is the Monterey Bay fault. Most if not all small to moderate earthquakes on the Monterey Bay Fault zone (MBFZ) have nearly pure strike-slip mechanisms and near-vertical dips.

The largest historical earthquakes appear to be on the Monterey Bay fault zone, including events on Monterey Peninsula. The northern San Gregorio Fault (SGF), in contrast, while more seismically active, has smaller events with oblique or thrust mechanisms. The results suggest that the primary strand of the SGF dips beneath Santa Cruz. The southern SGF zone, which defines Carmel Canyon and parallels the Big Sur coast, did not show any significant seismic events during the two years of instrument deployment. In addition, relocations of historical events do not show any seismic events for this strand of the SGF. The absence of seismicity could indicate that the regional strain is being fully accommodated by the adjacent strands of the MBFZ. Alternatively, this fault segment could be locked, and building strain until it is released by a large event.

At present time the creep rate of the MBFZ is not known. Past quakes in the Monterey Bay, which may be associated with the MBFZ ranged from 4.0 to 6.1.

It should be noted that some scientists think that Californians should take note in regards to tsunamis. The Monterey Bay Canyon, less than a mile off the shore of Moss Landing between Santa Cruz and Monterey, has sides sloping sharply down nearly two miles. Such steep drop-offs create ample opportunities for underwater landslides. Additionally, Monterey Bay itself is bisected by two faults, the Monterey Bay fault and the San Gregorio fault.

This information has scientists worried. A tsunami caused by an earthquake and subsequent landslide in Monterey Bay Canyon would occur much too quickly for a public warning system to be effective.

This by the way is thought to have already happened in the early 1900s. There was a 4.0+ quake in the Monterey Bay area. Moments later there was a drop in the water at Moss Beach only to return at a level 4 feet above its original level before returning to normal. The most probable cause was an undersea landslide.

Here is a little tidbit for those who like ghost stories. It concerns the Moss Beach Distillery, which is located on a cliff overlooking the ocean

During the Prohibition era of the 1920s, a young woman was murdered after her lover found her cheating with another man who was employed at the site. Today, "The Lady in Blue," lurks around the cliffs surrounding the building; she warns children not to play too close to the edge. In the area, there have also numerous reports of poltergeist activity. Such activities include: incessant telephone ringing, cases of wine being stacked behind the door leading to a windowless storage room, objects randomly being thrown about, and doors mysteriously slamming. Take Care…Don in creepy town