Long-period transition period, TL, for the conterminous United States, Alaska, Hawaii, Puerto Rico and United States Virgin Islands, 2009 NEHRP.

For designing buildings and other structures to safely resist earthquakes, the 2009 NEHRP Recommended Seismic Provisions and the 2010 ASCE/SEI 7 Standard contain maps...为开展可安全抵御地震的建筑及其他结构的设计工作，2009年NEHRP推荐抗震规程（National Earthquake Hazards Reduction Program）与2010年ASCE/SEI 7号标准（American Society of Civil Engineers/Structural Engineering Institute 7 Standard）均包含相关地图……