754 horizontal - component digital broad - band records in western north america are processed . the acceleration response spectra are calculated and used as part of the database . the response spectrum values are estimated by the earthquake magnitude definition and are used as another part of the database 将美国西部地区作为参考地区,对美国南加州地区的数字宽频带记录进行了搜集与处理后作为观测资料,共754条水平向记录,与利用震级定义所估计的反应谱值一起,用统计回归的方法建立美国西部长周期加速度反应谱衰减关系。