Seismologists have been studying California's faults for decades. They
now say that the San Francisco Bay Area has a 70%
chance of a major earthquake before 2030.
This forecast is based on years of study of the many faults in the area.
The map shows the probability of a quake from each of these faults.
Because of these high odds for a major quake, the new
East Span of the Bay Bridge must be able to withstand some serious shaking.
Caltrans (California Department of Transportation) decided that the bridge
must be able to absorb the worst earthquake that might hit the Bay Area
every 1,500 years. They call that the "Maximum
Credible Earthquake" or MCE. Seismically speaking,
that means the bridge must withstand an 8.2 magnitude quake (on the Richter
scale) on the two faults just a few miles away, the Hayward or the San
Andreas. That's 10 times more powerful than the 7.1 magnitude Loma Prieta
quake, which broke the Bay Bridge in 1989and that quake's epicenter
was thirty miles away!
How will they do it?
Try designing the bridge yourself in Engineering
for Earthquakes, or learn more about the people and technologies
involved in the construction of the bridge in Two
Miles & 2,000 Hands!