This note is to alert all past and current users of RefTek RT130 hardware that these instruments have been experiencing GPS failures in-field. To date, the failures are geographically confined to East Africa and symptoms include intermittent or total loss of timing.

It is worth noting that in reviewing close to two years of repair records, 1303 GPS have been returned to PIC from 69 experiments, excluding those in East Africa, and the total number of GPS units that needed any type of maintenance or repair was 30. There is no evidence at this time that there is a global problem with our RefTek GPS.

We are recommending that all users of EPIC RefTek RT130 dataloggers review their data and log files for signs of GPS failure that are consistent with the failures seen in East Africa. To identify failure behavior please visit this page for a brief tutorial. If you identify failures in your data, please contact passcal [at] passcal [dot] nmt [dot] edu and include "RT130 GPS failure" in the subject line and unit serial numbers in the body of the email.

On October 8-13, 2012, a three-man team from the EarthScope Transportable Array and EarthScope/EPIC installed a prototype "cold and dark" seismic station at Eagle Plains, Yukon Territory, Canada, just 30km south of the Arctic Circle.  The station installation developed new methodologies for drilling a shallow, 55" deep borehole in exposed bedrock. Protection for electronics, power, and communication subsystems (from the elements, and from large wildlife) was provided by an all-weather hut bolted to bedrock.

It's been a busy summer for EarthScope/EPIC intern Kasey Aderhold, a PhD Candidate at the Department of Earth & Environment, Boston University. Kasey has been heavily involved in an ongoing comparison of seismic vaults to direct burial installations at two sites: the Dotson Ranch near Socorro, NM, and Poker Flat in Alaska. 

This note concerns only those stations utilizing a remote autonomous power system and solar panels. Systems that will be using AC power should contact the PIC staff for more information on safely using these types of power sources.

Grounding of DAS units should only be attempted in extreme cases where static charge is a problem (for example, failing equipment such as external GPSes). Attempts to ground DAS units can lead to ground loops if not properly done, or even if done to best practices!  It should only be attempted when the sensor itself has been isolated from ground by a non-conducting plate such as a tile or phenolic pad.  Pads which are not part of the original vault design can also cause stability/noise problems, and must be well coupled to the base of the vault or concrete.