There is no seismic design code for offshore platforms in China and the commonly used criterion by offshore oil industry is RP2A-WSD which is based on the seismic hazard of coastal waters of the United States. A brief introduction is given to RP2A-WSD and the ground motion zonation of U.S. costal waters. For Bohai sea is a main source of offshore oil and gas where seismicity is high, the seismic characteristic and ground motion are discussed, then a comparison is made between the seismicity of Bohai and Southern California. On the basis of the comparison and the importance and characteristic of offshore platform, a proposition about seismic design level is put forward.
Keywords:offshore platform,RP2A-WSD code,seismic design level,Southern California,Bohai Sea