This article gives a description of our first study on ground rotational motion and its pre-liminary results. The ground rotational motions around vertical axis were obtained using near-field translational records of ...This article gives a description of our first study on ground rotational motion and its pre-liminary results. The ground rotational motions around vertical axis were obtained using near-field translational records of a temporal seismic array with observational distances of 1.8 to 2.7 km. The sources used are explosions with explosive of 500 kg for each. Ground rotational velocities were calcu-lated using the space derivatives of the horizontal components of translational velocities from the array. The peak ground rotational velocities （PGRV） are approximately 30 to 57 ？rad/s. Our results are very close to those from Wassermann et al. （2009）, who used both a seismic array and a rotational sensor to record an explosion in Germany and obtained PGRV values of about 50 ？rad/s. Their explosives are 150 kg, only one third of ours, but their observational distance is 250 m, much less than ours.展开更多
The apparent velocity of the incident wave is an important parameter for simulating rotational ground motion with theoretical methods, but it is difficult to estimate effectively when there is only a single record. Th...The apparent velocity of the incident wave is an important parameter for simulating rotational ground motion with theoretical methods, but it is difficult to estimate effectively when there is only a single record. This paper discusses a P-SV ratio method based on elastodynamic theory in a multi-layer isotropic elastic half space. The apparent velocities of four earthquakes in the SMART1 array are calculated with this method. The result is close to a method that uses travel time analysis. Furthermore, the factors that impact the apparent velocity and equivalent incident angle are considered according to records from the Chi-Chi earthquake. There is no obvious relationship between the equivalent incident angle and epicenter distance. However, the equivalent incident angle is obviously dependent on the site conditions.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 90814001, 40974053, 41074069)
文摘This article gives a description of our first study on ground rotational motion and its pre-liminary results. The ground rotational motions around vertical axis were obtained using near-field translational records of a temporal seismic array with observational distances of 1.8 to 2.7 km. The sources used are explosions with explosive of 500 kg for each. Ground rotational velocities were calcu-lated using the space derivatives of the horizontal components of translational velocities from the array. The peak ground rotational velocities （PGRV） are approximately 30 to 57 ？rad/s. Our results are very close to those from Wassermann et al. （2009）, who used both a seismic array and a rotational sensor to record an explosion in Germany and obtained PGRV values of about 50 ？rad/s. Their explosives are 150 kg, only one third of ours, but their observational distance is 250 m, much less than ours.
基金the National Science Foundation of China Under Grant No.90815026 and 50638010the National Seismic Project Under Grant No.200808074
文摘The apparent velocity of the incident wave is an important parameter for simulating rotational ground motion with theoretical methods, but it is difficult to estimate effectively when there is only a single record. This paper discusses a P-SV ratio method based on elastodynamic theory in a multi-layer isotropic elastic half space. The apparent velocities of four earthquakes in the SMART1 array are calculated with this method. The result is close to a method that uses travel time analysis. Furthermore, the factors that impact the apparent velocity and equivalent incident angle are considered according to records from the Chi-Chi earthquake. There is no obvious relationship between the equivalent incident angle and epicenter distance. However, the equivalent incident angle is obviously dependent on the site conditions.
