震源近傍の加速度記録を用いたM_Lの決定

抄録

Using the near-field strong-motion records obtained at Usu and Matsushiro, Japan, we develop the technique for determining Richter's local magnitudes M_L to earthquakes recorded at very short distances. To determine M_L we use the integrated ground velocities and the amplitudes on the standard Wood-Anderson records which are synthesized from accelerograms. The present scale is intended to coincide with the scale used for local earthquakes in Japan, which is logically consistent with the original M_L scale. The distance-correction term is determined over the epicentral distance from 0 to 20km. The newly obtained values are slightly different from the original values. The results can be applied to near-field accelerograms of earthquakes in California as well as Japan.