>>2991232

This → >>2991246

Also, how does the residual time indicate drilling?

"Residual time" corresponds to the error in location that can not be "evened" out after inversion of all the station data for the epicenter (or hypocenter).

It has nothing to do with what caused the signal arriving at the sensor.

>2991315

No (you) for you – 'cause you must be pretty dumb, and certainly don't belong here – but they pay you. So work harder!