Development of a method to detect traffic volume by making use of high-sensitivity seismometers

提出了一种利用高灵敏度地震仪估算交通量的实用方法。该系统由高灵敏度地震仪、放大器、A/D转换器和个人计算机组成。初步观测表明，在位移维度上的垂直地面运动最适合于检测行驶中的车辆。当车速足够高时(约20公里/小时或更高)，可以通过地震仪的距离和到达时间差来准确地估计运行速度。由于诱发子波的宽度随着运行速度的提高而变窄，因此实际上可以从一台地震仪记录的一个子波来评估运行速度。当车速较低时(约10公里/小时或更低)，不能观察到显著的子波。但是，当路面临时安装一个小的橡胶凸台时，会产生一个显著的小波。对子波进行速度维分析时，可以很容易地检测到子波。在公共道路上的观测表明，感生子波的形状与行驶车辆的质量有关。这一差异使我们能够区分车辆的类型。

A practical method to evaluate traffic volume is developed by making use of high-sensitivity seismometers. The system consists of high-sensitivity seismometers, amplifier, A/D converter, and personal computer. Preliminary observations show that vertical ground motion in displacement dimension is the most appropriate for detection of running vehicles. When vehicle speed is high enough (about 20 km/h or more), the running speed can accurately be evaluate with the distance of seismometers and the difference of arrival time. Because the width of induced wavelet becomes narrower as running speed becomes higher, running speed can practically be evaluated from a wavelet recorded at one seismometer. When vehicle speed is low (about l0km/h or less), significant wavelet cannot be observed. However, a significant wavelet is induced when a small rubber bump is temporarily installed on road. The wavelet can easily be detected when the wavelet is analyzed in velocity dimension. Observations in public roads show us that shape of induced wavelet is related to the mass of running vehicles. The difference allows us to distinguish the type of vehicles.