Analysis of Impact of the Tonga Volcanic Eruption in 2022 on the Strain Observation of Chinese Mainland

  Objectives  The Tonga volcano erupted violently on January 15th, 2022, which produced atmospheric gravity waves affecting around the world, and was clearly recorded by all ground strain observation stations in Chinese mainland with the distance from 8 736 km to 12 758 km.

  Methods  The wavelet analysis method is applied to systematically analyze the spatial-temporal response and frequency characteristics of the data recorded by nearly 200 ground strain observations in China.

  Results  The results show that the duration of change is about 1.5 hours, in which the strongest energy change is occurred at the first 40 minutes. The average amplitude of surface strain is about 186×10^-10, showing a single pulse as rise and fall change, and the patterns have highly consistency with Lamb wave propagation properties. The average velocity of event propagation is 310 m/s, which is consistent with the propagation velocity of atmospheric gravity waves. Most stations also record the effect of atmospheric gravity wave signals on the surface as they arrive twice around the Earth.

  Conclusions  It is the first time to record the traces of atmospheric gravity waves acting on the surface through a large scale high-precision ground strain meters and it is helpful to understand the mechanism of interaction between crustal movement and atmospheric sphere.