What I infer is that the USGS is doing what they say on their site they do, defaulting to ten km. if they can't precisely determine the depth. It used to be 33 km. https://www.usgs.gov/faqs/why-do-so-many-earthquakes-occur-depth-10km There are a number of people who believe that everything happening at 10 km. depth means that someone is blowing up an underground fortress of satanic pedophiles. Real demons maybe. Constructing all the projected pedophile bunkers and tunnels to cover so many earthquakes at either 10 or 33 km would have taken most of the world's resources for centuries and living there would not work for carbon based life but hey.