What_the_Beep

A strange beep sound was heard across a part of the San Joaquin Valley. We have the records from some audio volume meters at various locations nearby that picked up this event. It's understood that the original sound was 140 dB at the source, but can you find out where it originated from?

When you find out, submit the coordinates to the answer checker service to get the flag.

Note: you may assume perfect conditions.