北欧气旋风暴与欧亚大陆的震动

The vibration of Eurasia induced by the Nordic cyclone storm

全球地震台网(GSN)及中国地震台网(CENC)的地震观测数据分析表明:由北大西洋、北冰洋等海域进入北欧的强冷涡气旋(北欧风暴)能引发与其过程相关联的震动,其中由挪威海登陆斯堪的纳维亚半岛的强气旋风暴引发的震动波,几乎可以被整个欧亚大陆的地震仪观测到,该震动主要包含两个信号:一个主频为0.15~0.25 Hz(周期约4~7 s);而另一个是主频为0.08~0.12 Hz(周期8~12 s)的面波信号,它们分别来自不同的产生机理.不同海域和地区的风暴引发的震动信号存在差异,与气旋运动路径经过的地形地貌特征有关,气旋经过的浅海区域、海水深度、登陆地点的地形以及气旋的结构、观测点相对气旋的分布等因素决定了气旋在运动中激发有独特的震动信号.地震观测可以监测气旋在时间和空间的发展变化过程,有助于探索气旋运动过程中与地球表面的相互作用对气旋的影响.

Analysis of the observational data of Global Seismic Networks （GSN） and China Earthquake Networks Center （CENC） suggests that the strong cold vortex cyclones in northern Europe （Nordic Storm） from the North Atlantic and Arctic Ocean can cause vibrations of the continent. For example, the vibration caused by the strong cyclone storm in Scandinavia landing from Norway Sea has been observed by nearly all the seismographs in Eurasia. There are two main signals in the observation of such vibrations： one signal whose frequency is mainly in the band of 0.15~0.25 Hz （4~7 s in period）, and the other one is surface waves which are at frequency from 0.08 to 0.12 Hz （about 8 to 12 s in period）, while each of which is generated by a distinct mechanism. Because of the differences of storms in different seas and land areas, the vibrations caused by them differ from each other. These differences might be related to the landform characteristics of paths the storm passed, meanwhile the special vibration signals excited during the movement of the cyclones are also depend on the shallow sea where the cyclones passed, the sea depth, the landform of the landing site, the cyclones＇ structure and the position distribution of observation sites with respect to the cyclones. Seismic observations permit to monitor the development and change processes cyclones in time and space, which are much helpful for the research of the influence of the interaction between the cyclone and the surface of the earth during the cyclone motion.