It was a bright summer afternoon and i was enjoying the last few weeks of the season with my daughter in the backyard. Suddenly i see my patio wobble and i didn’t realize until later that it was an earthquake. A 5.8 magnitude earthquake hit Virginia on Aug 24th 2011 and shook the entire east cost. Although northeast does not receive any serious earthquakes, a few destructions like the large crack in the Washington’s oldest monument and damages in the National Cathedral were reported. Are building codes slack in east coast when compared to west cost?
Earthquake hazards exist all over united states. The seismic facilities of the International Building Codes appeal for the entire nation. However, the specific requirements differ based on the seismic hazard maps. The degree of shaking over a period of time is predicted by the U.S Geological Survey national and regional seismic- hazard maps. Consecutive changes in the maps are restored in the building codes.
Areas in the west for instance in California, earthquake usually occurs in the known fault line. Unfortunately on the east cost they do not correlate with the fault line and the quiver is more intense through the hard rocks. Very few fault lines are predicted on northeast and no much analysis are done. Based on the fault lines and the make up of earth in a particular zone, the codes place the maximum movement the buildings can bear in that specific area.The magnitude of earthquake is usually measured in Richter scale and the Modified Mercalli Intensity (MMI) Scale.
After the 1971 earthquake which hit most of the areas north of Los Angeles, western U.S has revised the building codes. The wall anchors, brick walls and masonry structures must all meet the specifications for construction. The result of the improved building codes were seen in consecutive earthquakes in 1987, 1991, 1992 and 1994 that brought about only minimal damages. However, in eastern U.S seismic building codes became effective only from mid 1990s.
The Northeast cities are most densely populated in United States. According to the earthquake facts reported by the Northeast States Emergency Consortium, the thick populated nature of the northeast cities puts people here at higher risk. Northeast is also home to many historic and older buildings which are not reinforced masonry structures and are definitely a big threat to destruction in the occurrence of an earthquake. The recent east cost quake is very faint when compared to the western U.S but for many years California has always constructed with building codes to tolerate the big earthquakes. We cannot afford to loose the iconic buildings in New York and Washington D.C. It is time for us to arise, preserve the existing architecture of the eastern U.S and use the western U.S building codes for the new constructions.