Earthquakes

Shaking: condition of tremors and jostling that occurs during an earthquake

The initial shaking was reported to have lasted more than a minute and aftershocks were reported to have continued into the next month (Destruction 1868).

The massive shaking was preceded and followed by strong movement. The earthquake itself lasted 45 seconds.

Liquefaction: occurs when the ground becomes water-saturated; damages foundations of buildings and other structures

Liquefaction at the time of the earthquake was reported to be substantial enough to have damaged several important structures.

Liquefaction caused much of the damage following the quake. Most of the damage caused by liquefaction occurred in "reclaimed areas" which has once been bay or marshland.

Rupture: a tear in the rocks moves along the fault plane until it dies out

1868: Earthquake ruptured the southern segment of the Hayward Fault, from Berkeley to Fremont, CA; a distance of 20 miles (Berkeley 2005).

1906: The earthquake was approximately 8 on the Richter scale, creating severe rupture damage from San Francisco and outside the city.

Landslide: condition where large masses of land move from one location to another

1868: Landslide damage unknown; all damage to buildings attributed to shaking and/or rupture.

1906: It is unknown how much damage was done to the environment because of landslides.

Tsunami: a very large ocean wave caused by an underwater earthquake or volcanic eruption

1868: No tsunami reported

1906: No tsunami reported

Potential hazards of San Jose, CA:

The greatest potential hazard to the area of San Jose, California in the present moment is the possibility of shaking damage, rupture damage, and landslide. Earthquake proofing has done some to protect larger buildings from damage such as liquefaction, but there is still severe potential harm if an earthquake hit which was a 7.0 on the Richter scale or above (California's 2007). Shaking and rupture damage are the most dangerous. However, in locations which are close to large water sources, such as those on the ocean shore are more likely to have sever damage due to liquefaction. Locations with geographic features with steep inclines are in worse danger of landslides. Historically, tsunamis have not been a problem in this part of the world.

Works Cited:

"Berkeley Seismological Laboratory: 1869 Earthquake." (2005). UC Berkeley.

http://seismo.berkeley.edu/faq/1868_0.html

"California's Hayward Fault Revealed: Most Dangerous Urban Fault in America?" (2007).

Science Daily.

"Destruction of Property in Various Parts of the City." (1868). The San Francisco Morning Call.