Abstract: Based on the single scatter model (Aki), value of coda was calculated in Jiujiang—Ruichang earthquake-stricken area in Jiangxi province, using digital seismic wave recorded by five stations whose epicenter distance was less than 30 km. The result shows the seismic coda attenuation feature in the relative region as follows: ① The value of varies form 70 to 79, based on value of η, the result showed two kinds of change, the η value, obtained from these wave data recorded in the Jiujiang and Fangzhen stations, varies from 0.86 to 0.88, the other value, obtained from the wave data recorded in the Dingjiashan, Shizidong and Wujiao stations, varies from 0.94 to 0.97. The deference among the value of η may correlated to the direction of stations which recorded these wave. Taking the size of the earthquake rupture into account, the mean coda attenuation coefficient in the area was obtained just using the wave data obtained from the late 3 stations, the result is Q_c(f)=(77.5±15.6)f^0.96±0.09. ② The result is in accordance with what obtained in Wuding Shidian area in Yunnan Province, the result may show that the geologic structure is identical in the two areas. In the study 40~44 s of elapsed time windows were used to calculate the attenuation coefficient, the corresponding sampling depth is about 53 km. The result shows the attenuation feature of the earth crust and the upper mantle in the area.

Key words: Value of coda, Jiujian-Ruichang earthquake-stricken area, Feature of medium