Highlight one of the earthquake occurrences on the list on the left of the map at the La Palma site. When you magnify the map to its highest setting it will show the grid pattern the video is talking about. Earthquakes don't occur naturally in a grid pattern it seems to reason.
You can also go to the European earthquake monitoring website.
https://www.emsc-csem.org/Earthquake/Map/gmap.php
Highlight one of the earthquake occurrences on the list on the left of the map at the La Palma site. When you magnify the map to its highest setting it will show the grid pattern the video is talking about. Earthquakes don't occur naturally in a grid pattern it seems to reason.