Broadband

The Geophysical Earth Observatory for Ice-Covered Environments (GEOICE) project was a NSF collaborative Major Research Instrumentation (MRI) program that expanded the EPIC Polar group’s observational capabilities and logistical efficiencies. GEOICE developed a rapidly deployable, dense footprint seismic observatory system for operation in ice-covered areas. The GEOICE project was a collaborative effort between Central Washington University (CWU), Incorporated Research Institutions for Seismology (EarthScope) and the Portable Array Seismic Studies of the Continental Lithosphere (EPIC) Instrument Center at the New Mexico Institute of Mining and Technology.

Note:  EPIC has purchased 11 Nanometrics Trillium 120PH seismometers.

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.

Salient Features: Flat response to velocity from 120 seconds to about 10 Hz Low power Installation Tips: Example of STS-2/RT130 Setup One-pager field sheet

  Troubleshooting Tips: If you cannot center the masses of even one of the 3 elements of the STS-2, all your data could be compromised. The document provided here will guide you to a 'manual' process for attempting to get those masses centered, IF and ONLY IF the masses do not center after repeated (a dozen tries) centering commands.  

Nanometrics Trillium 240

The Nanometrics Trillium 240 is a symmetric triaxial broadband instrument that has a flat response to ground velocity between 240s and 200Hz, and has a low self-noise, below the New Low Noise Model between 100s and 10Hz.  The manufacturer specifications of operating temperatures are between -20C and +50C, but the Trillium 240 has operated reliably for us to temperatures below -60C.  The power consumption at low seismic noise conditions and with the instrument well leveled is about 650mW.  The Trillium has a +/-1deg tilt tolerance, is fairly sensitive to varying temperature, but was designed to be insensitive to atmospheric variations.

The Trillium 240 is well suited for medium to long term experiments in the Arctic and Antarctic supported by the EarthScope EPIC Polar Program.

Salient Features 30sec to 50 Hz flat velocity response Manual Mass locking/unlocking Remote Mass Centering Response Characteristics:

EPIC Broadband Sensors: Streckeisen STS-2 Guralp CMG-3T Nanometrics Trillium 240 Nanometrics Trillium 120 Features:

The Cold-rated Guralp CMG-3T seismometer is described in detail in the Polar section article "Sensors for Year Round Polar Programs".

  Salient Features: 120s - 50 Hz flat velocity response Remote electronic mass locking, unlocking and centering. Installation & Troubleshooting Documents: Example of 3T/RT130 setup One-pager field sheet
Manufacturer's Documents: Guralp CMG-3T Manual Datasheet, Manual & Quick Start Guide