Wednesday, March 19, 2008

Society on an Active Plate Boundary

The people of Washington State are a society that lives on an active plate boundary and with volcanoes. My essay will tell you how they live with these dangers. The communities of Washington State have made several adaptations for protecting themselves against the dangers. Some systems that they have developed to adapt for structural damage caused by earthquakes include hybrid solutions, base isolation, dampers, slosh tanks, shock absorbers, tuned mass dampers, retro fitting, and active damping with fallback. These systems are either made to counteract movement, strengthen the buildings foundations or to strengthen to building structure. Hybrid solutions are a program for the development of structural methods. This system is made of post tensioning and external energy dissipation. Fiber reinforced concrete is needed for plastic hinging. This helps allow structural joint failure without massive joint failure. Base isolation is done to reinforce the structures foundation and reinforce it from the shaking ground. Dampers absorb energy of motion and convert it to heat. This reduces resonant effects on structures that are strongly attached to the ground. Slosh tanks are put in place to counteract the motion caused by earthquakes. Shock absorbers do the same thing but between two buildings. Active damping with fallback I s the same thing as a slosh tank but is controlled by a computer and is done with weights, and is used more commonly in skyscrapers. Retro fitting makes reinforces a buildings structure with steel. For protection from volcanic eruptions scientists have put in place a warning system. This warning system has four stages, normal advisory watch and warning. Normal means typical background activity in a non-eruptive state. Advisory means elevated unrest above known background activity. Watch means heightened/escalating unrest with increased potential for eruptive activity with limited hazards. Warning means highly hazardous eruption undergoing or imminent. There are also color codes put in place for the international civil aviation organization. The ICAO uses these color codes to direct air traffic around ash-polluted areas. In conclusion the state of Washington has had many advances and put in place many systems to protect the people of its state. NE1

1 comment:

student08 said...

fun to read very intresting that would be scary to live on actice plates (PM5)