> there is clearly a low-intensity lead-up. Explosions don't do that
If you had studied harder, you'd know that it's more difficult than this to distinguish b/w earthquakes & explosions, and that there are more factors to take into account.
Here's an earthquake w/o "low-intensity lead-up" (left), and an explosion with some "low-intensity lead-up" (right)
But please go ahead. I'm always glad to learn something new.
>"snap"
That's possible, but it's really not that easy. For EQs one can establish a so-called "radiation pattern", for example. If your sensor is near one of the nodal planes, the eq might have that appearance.
Also, distance to eq, geology (hard rock, soft rock), type of sensor, type of fault and other factors play a role.
This has been studied as a separate subject (seismology) for more than 100 years, and it still is difficult.
Just saying ….