资源环境科技发展态势分析平台

Tornadoes generate seismic signals when they contact the ground. Here we examine the signals excited by the Joplin tornado, which passed within 2 km of a station in the Earthscope Transportable Array. We model the tornado-generated vertical seismic signal at low frequencies (0.01-0.03 Hz) and solve for the strength of the seismic source. The resulting source amplitude is largest when the tornado was reported to be strongest (EF 4-5), and the amplitude is smallest when the tornado was weak (EF 0-2). A further understanding of the relationship between source amplitude and tornado intensity could open up new ways to study tornadoes from the ground.

Plain Language Summary When a tornado touches down, its winds and air pressure shake the ground, creating small, but measurable, seismic waves. We look at these waves created by the Joplin tornado in Missouri (2011), which happened to pass close to a seismometer. We modeled these waves to find out how large of a force the tornado is exerting on the ground. We found that the force is largest during the time when the tornado was reported to be strongest (EF 4-5 on the Enhanced Fujita Scale) and smallest when the tornado was weak (EF 0-2). Further understanding this relationship could open a new way to study the strength of tornadoes by seismic waves.