Shake-y Shake-y

Standing on Shakey Ground

punkrockmichelle

All kidding aside, it seems like a good time to take a closer look at the Liquefaction map, and the Seismic Hazards Maps.  Prior to purchasing property here, you may want to look at the properties location on the hazard maps, to see if it is located in a liquefaction or landslide zone.  

geoIQ

When the earth shakes, the underlying earth material is of differing degrees of "shake-ability". Bedrock is the most stable, though it varies depending what kind of bedrock, and mud and fill are the least stable.

Museumca.org

The liquefaction map looks very similar to creek and watershed maps, which is because much of the liquefaction area is fill, (old ships and garbage) placed in former creeks and wetlands. In these areas, the ground can turn from a solid to a liquid state when shaken, causing increased likelihood of buildings being shifted off their foundations or worse. 

mceK12

The golden gate hills offer up exposed bedrock, or a covering layer of less consolidated rock or soil, and often a mix of the two. The variable substrates can be subject to different types of landslides, which can be triggered by earthquakes, or by high levels of rainfall.

SLU

The extreme variations in damage and death tolls we see with earthquakes, often house by house, have to do with proximity to epicenters and variable substrates but also building codes, materials and practices. For example, Port au Prince Haiti was close to the 7.0 epicenter, with largely unreinforced masonry construction and an enormous death toll, while the recent 8.8 Chilean earthquake killed less than 1,000 people, due to the distance of the epicenter from major population centers, and to building codes.

America's North Shore Journal

Earthquake insurance is expensive and limited here in our earthquake prone locale.  We'll take a closer look at our local earthquake related real estate issues in Shake-y Shake-y Part 2...

USGS

in the meantime, you can check out this cool link to earthquakes round the world.




(Thanks to Judith Sheridan and Zoe Cooper-Caroselli for your insights)