The waves from Q's drop? This event occured on 11.11.18 and scientists are unsure why.
Unusual Seismic Waves Shook The Earth On Nov. 11 & Scientists Still Don't Completely Know Why
https://www.bustle.com/p/unusual-seismic-waves-shook-the-earth-on-nov-11-scientists-still-dont-completely-know-why-13221267