Characteristics of Arias intensity and Newmark displacement of strong ground motion in Lushan earthquake

The characteristics of spatial distribution, attenuation and correlation of ground motion parameters are important research contents in engineering seismology. In this paper, based on the ground motion records of Lushan earthquake, we study the spatial distribution and attenuation characteristics of Arias intensity and Newmark displacement as well as their correlation with other ground motion parameters, respectively. The results show that the spatial distribution of Arias intensity is related with the spatial distribution of seismic faults and the direction of earthquake rupture. Arias intensity has a good correlation with PGA. Furthermore, the site conditions have a significant effect on the correlation between the two: for the same PGA, the softer the site condition, the greater the Arias intensity. In addition, magnitude is also an important factor affecting the correlation between Arias intensity and PGA: with the same PGA, the greater the magnitude, the greater the Arias intensity. Newmark displacement has a good correlation with both PGA and Arias intensity, among which the correlation with Arias intensity is stronger, and the correlation coefficient can reach above 0.94. The research in this paper also shows that the existing models cannot describe the attenuation characteristics of Arias intensity and Newmark displacement of Lushan earthquake well, which indicates the particularity of Lushan earthquake in both the duration and rupture process. The particularity of Lushan earthquake reveals that the seismic geological and tectonic environment in Western China is significantly different from that in other regions. Therefore, the prediction equations of ground motion parameters suitable for earthquakes in Western China should be studied. The research results of this paper have important scientific significance and application value for us on both understanding the characteristics of ground motion and the prediction and prevention of earthquake disaster in China.