Fig. 9
From: Seismic noise between 0.003 Hz and 1.0 Hz and its classification
(top) Tornadoes generate airwaves and seismic waves. Seismic waves primarily come when a tornado touches the ground. Because the pressure in the interior of a tornado is low (due to fast wind speeds), things get sucked upward. (Bottom) The pressure source along the tornado track was inverted and shown as a time series. When the tornado was strong (EF4–5), the pressure source was strong, and when it became weaker (EF0–2), the pressure source became weak. Seismic data may be used for quantitative analysis of the effects of tornadoes