The upper part of the mantel and the crust make up the lithosphere. The lithosphere is the dense, solid layer that surrounds the earth; we call it the ground. There are giant plates that sit on top of the earth's mantle. These plates are very large rigid slabs of crustal rock that float on top of the mantel. The lighter plates carry the most landmass and the more dense plates carry less landmass. These plates are like large sheets of ice siting on top of a pond and like th

Earthquake design in the Bay Area has become a pressing issue because we have seen the damage an earthquake can cause and we are trying to prepare for the next one We now know the importance of earthquake safety in the bay area. The San Francisco Bay Area is part of a very complex plate boundary system between the pacific and the northern American plates. Near Hollister, the Calaveras fault branches off from the San Andreas Fault towards the north. The Hayward fault branches off from the Calaveras towards the northwest. At a much smaller scale many thrust faults run parallel and cross the San Andreas Fault. Although most of the present day seismic activity in the Bay Area comes from the major faults (San Andreas, Hayward-Mission creek, Concord-Calaveras, and the Antioch faults) and an additional ten percent happens in the minor and unmapped faults. Geologists and engineers use risk assessment maps, such as geologic hazard and seismic hazard zoning maps, to understand where faults are located and how to build near them safely.

e ice they do not sit still. Scientist believe that the plates are driven by convection currents in the mantle. There are nine major plates. These plates have boundaries. There are different types of boundaries. A divergent boundary is when two plates move apart from one another. A convergent boundary is when two plates move towards each other. A transform boundary is when two plates slide horizontally past each other these boundaries are also called faults.

In urban areas of the Bay Area, the seismic risk is greater in non-reinforced buildings made of brick, stone, or concrete blocks because they cannot resist the horizontal forces produced by large seismic waves. Fortunately, single-family timber- separation. Although they may suffer some damage, they are unlikely to collapse because the strength of the strongly jointed timber-frame can easily support the light loads of the roof and the upper stories even in the event of strong vertical and horizontal ground motions. Frame homes built under modern construction codes resist strong earthquake shaking very well. Such houses have laterally braced frames bolted to their foundations to prevent this.

If the next big earthquake hit maybe a 9.0 or higher I believe that are current earthquake design of buildings would be ineffective. When they do testing for earthquake design in the lab they reenact past earthquake. I think they should not reenact past earthquake but may simulate more sever earthquakes. By doing this we are preparing for the future.

Some common words found in the essay are:
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Approximate Word count = 2588
Approximate Pages = 10 (250 words per page double spaced)