January 9 is the anniversary of the last big event on the San Andreas, and thus we have more than passed the 150 year anniversary of that quake.  It is generally regarded as one of the most powerful in US history.  Many sources believe it was at least as large, and probably larger, than the San Francisco earthquake of 1906, with an estimated magnitude of at least 7.8, and more probably 8.0, and shaking intensities of at least X - XII on the Modifed Mercali scale.

The quake hit in the morning, between 8 and 8:30 as many people were finishing their breakfasts.  There's at least one reasonably reliable report that indicates the shaking lasted somewhere between 40 and 60 seconds ....at some distance away from the epicenter.  This may imply that shaking closer to the epicenter may have been longer, as forces tend to fall off rapidly with distance.  And there are some reports that do indicate the shaking in the epicentral areas lasted from one to three minutes.

News reports of this quake indicate it was felt all up and down the state (California), and given the size, probably was felt out of state as well.  Many reports and diaries indicated that nausea and a kind of sea-sickness or vomiting was a common reaction to the violent shaking (ask us about motion bands).

A number of rivers catapulted the water out of their channels.  The Kern River not only flooded, but reversed course and flowed upstream for a while.  In one diary it was noted that Tulare Lake had run out over three miles from it's usual location, and as it receded left fish stranded in the mud, as a feast for the vultures.

Many ruptures or fissures in the ground appeared in numerous areas.  Some wells suddenly went dry but, in other areas, new ones appeared.  The trace itself showed over 230 miles of surface ruptures from Parkfield (in Monterey County) to south of Wrightwood near the Cajon Pass (in San Bernardino County), with horizontal displacements up to 32 feet. 

Even now, travelers going over "The Grapevine" pass through the Ft. Tejon pass.  What all of us need to remember is that this pass became IMPASSABLE --- even to single horseback riders! ---- due to the number and scope of the rock slides that were caused by the quake.  Another quake of similar size could easily cut off the LA basin from highway access in or out.

Some sources indicated sharp jolts were felt in Santa Barbara the night before, in what was probably an escalating series of related foreshocks.  At least one account suggests there may have been a syjmpathetic rupture adjacent to the SAF zone in what is now southwestern Kern County.

Mission San Buenaventura was heavily damaged. 

Deaths and injuries were quite limited because the areas were sparsely populated, and there were few buildings.  There was also no infrastructure to be damaged, such as what our current densely populated areas are now dependent upon.

According to a study conducted by researchers from Cal Tech and Central Washington University, all San Andreas quakes in the last 1,000 years have been big, and there is no sign of smaller events that might have relieved or transferred pent-up pressure.  The smallest registered just below a 7.  Five of the last six earthquakes caused the fault to slip 15 - 25 feet.  Shaking in a future quake on the southernmost section of the fault, especially between the Cajon Pass and Salton Sea (further south than the 1857 event) is expected to last in most areas of Southern California for around two minutes.  From start to finish this coming quake is expected to last almost four minutes from initiating near the Salton Sea until the shaking pools then finally dies out in coastal areas, lingering in those areas largely due to soils subject to liquefaction.