Possibly activity in local area. OP 54000i Horizontal channels are very noisy after large data spikes. Confirmed the problem is downhole and we need to replace the seismometer. Re-centering instructions sent to the operator. Trouble shooting in progress.
Photographs reveal that there is no cover over the seismometer.
Digital commands not recognized by seismometer. Replace sensor when unit is available. OP Long period noise on the E channel has not settled down since seismometer installation in Sept 1993. FE visit required to replace KS36000i seismometer. Possible cable problems.