Q is referring to this:
https://www.outerplaces.com/science/item/19109-seismic-wave-earth-november-11
https://www.bustle.com/p/unusual-seismic-waves-shook-the-earth-on-nov-11-scientists-still-dont-completely-know-why-13221267
"Many factors combine to make these seismic waves exceptional. First, there’s the distance they traveled: The Earth’s circumference measures not quite 25,000 miles; with the waves covering 11,000 miles, they literally stretched almost halfway around the world. Then, there’s their regularity: Whereas a typical earthquake would have produced waves of many different frequencies, these waves were “monochromatic,” consisting of one shape — what National Geographic described as “a clean zigzag” — repeated at regular intervals of 17 seconds. As volcanologist Helen Robinson, a PhD candidate at the University of Glasgow, put it to the Independent, “They’re too nice.” And lastly, there’s the fact that no humans reported feeling the waves in any way. Indeed, one of the main reasons they've become so publicly known since then was because an eagle-eyed Twitter user based in Wellington, New Zealand spotted them while watching the real-time seismogram displays run by the U.S. Geological Survey and launched them out into the Twittersphere."
17 SECONDS