Routine maintenance tasks required this year
to keep the HRSN in operation include cleaning
and replacement of corroded electrical connections; grounding
adjustments; cleaning of solar panels; re-seating, resodering and
replacement of faulty pre-amp circuit cards; testing and
replacement of failing batteries; and insulation and painting
of battery and datalogger housings to address problems with low
power during cold weather.
Remote monitoring of the network's health using the Berkeley
Seismological Laboratory's SeisNetWatch software is also performed to
identify both problems that can be resolved over the Internet (e.g.
rebooting of data acquisition systems due to clock lockups) and more
serious problems requiring field visits.
Over the years, such efforts have paid off handsomely by
providing exceptionally low noise recordings
of very low amplitude seismic signals produced by microearthquakes
(below magnitude 0.0Ml) and nonvolcanic tremors.