“微震”用英语怎么说？

微震的震中位于苏尔特湾。The tremor was centred in the Gulf of Sirte.约5分钟之前,在距东京不远的千叶市也有过一次微震.A weak quake shook Chiba, near the capital, about five minutes earlier.微震的噪声谱在1/6赫趋于峰值.The spectrum level of microseismic noise tends to pe...