The header on this page is a view of the Crystal Springs Reservoir, which extends along Highway 280, south of San Francisco. Beyond the lake, you see the fog draping over the Santa Cruz Mountains. I love this view, and every time I drive on Highway 280 I think of how lucky we are to live in such a beautiful place.
What lies underneath this beautiful, peaceful lake is our very own San Andreas Fault, which is one of the main fault lines that make our neighborhood an “Earthquake Country.” For all I know, you may be looking at the location of the next fault rupture that will create our next big earthquake.
The picture at the header is a constant reminder that we indeed live in a beautiful place, but we also live in an active earthquake region. As residents of the Earthquake Country we need to recognize the risks we are facing and prepare for the next “Big One.” Making sure that our homes are “safe & sound” is a very important part of our earthquake preparedness.
Here is an article for those who would like to read a bit more about this topic.
BoomereseBlog 
Onder: Great little ‘blog’. My first time looking at one. The referred-to article was a nice one regarding the San Andreas fault and the Bay Area. Now I must ask you a question regarding the history of Crystal Springs. I’ve always understood that the ‘creation’ of this ‘reservoir’ was originally done to preserve a mass of water that would ‘help’ provide the waters to both San Franciso and the Peninsula in case there were future ‘quakes’ that would cause fires to occur. As it is ironic that it occurs directly over the San Andreas would this water source ‘actually’ be of any benefit to SF and the Peninsula if needed?? Seems to me that it would find its way [during a major tremor along this fault line] into the ground, possibly thru the dam [if damaged], and down the creek flooding homes in Hillsborough and San Mateo along the way. I’ve always wondered about this whole concept of the lake being there for ‘help’. What’s your take and/or knowledge on this???
IT IS TRULY a beautiful area. As a boy in ‘the scouts’ we used to hike the trails in the watershed to the west side hills north of 92. In addition, before the bike/walking trail was a dream and eventually developed along Camp Sawyer Road, we used to walk, bike, hike, have picnics, and even ‘drive’ along it. Great memories, for a time when there weren’t too many people enjoying and abusing it as is the case now. Still a beautiful place, but way too many people and dogs and such.
Hi Bill,
Welcome to BoomereseBlog. I am not familiar with the original reasons for the Crystal Springs reservoir (may be someone who knows it could fill us in). Currently it serves as storage for San Francisco’s water supply. The article I referenced at the end of my blog (just click on “Here is an arrticle”) answers your question about why the water does not drain down the fault scarp: the fault “grinds up the rock underneath creating an impermeable layer…” I believe the lower dam and the associated towers and culverts are currently being “seismically retrofitted” and, when the project is completed, the chances of a dam failure due to an earthquake should diminish.
You brought up a good point. Fires started by earthquakes and floods created by dam failures can sometimes indirectly cause as much or more damage to buildings than the ground shaking does. These are additional risk considerations that one could look into when deciding where to buy a house.
Yes, it is undergoing a seismic retrofit. Tried to drive by the dam yesterday while in the area and it was barracaded for no access to public. I’ll check out this site/article you referred my to. Later. LQQKing forward to the next visit/article, Doctor K.
YES, this is a decent article on the whole ‘280’ corridor and its ‘seismic’ issues and such. It’s cross-referencing to other articles is of interest too.
San Francisco? Very good. http://calogeromira.wordpress.com