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Here are some of the articles that have been recently posted to the PASSCAL website:

Intermediate Sensors

PASSCAL Intermediate-Period Sensors: Guralp CMG3-ESP Guralp CMG40T Nanometrics Trillium40 Features:

The low-period corner is 30 seconds for the 3 Guralps and is 40 seconds for the Nanometrics sensor. All are 3-component feedback sensors. The CMG40T and Trillium40 masses do not lock. One should still ship and handle them with care so as not to damage them. The CMG3-ESP has masses that require manual locking and unlocking.  For information on the CMG40T with corner-frequencies of 1-sec, click here.

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Geospace Y-28 (GS11-3D) High Frequency Sensor

  Salient Features: This 3-channel sensor has a frequency of 4.5Hz, is critically damped at .707 and has a sensitivity of 32 V/m/s. Used for (but not limited to) active source (land and off-shore excitations), glacial movements, local earthquake and aftershock studies. Manufacturer Website: PASSCAL Documents: Connector wiring information here Installation & Troubleshooting Documents: Y-28 Orientation and Installation Tips here One-pager field sheet
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4.5Hz High Frequency Single Component Sensor

Salient Features These single component geophones are available as vertical units for use with the Texan digitizer and as vertical 6-channel strings for use with the multi-channel digitizer systems.  The multi-channel strings are rarely used. This single channel vertical geophone has a frequency of 4.5Hz, damping of .707 critical and a sensitivity of 100 V/m/s. The primary use of these geophones is for active source experiments. Manufacturer Documents: PASSCAL’s 4.5Hz, vertical geophones were manufactured by Geospace under part number GS-11D. Installation & Troubleshooting:

 Installation requires a separate bubble level to be placed on top of the geophone for proper leveling.

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Solar Panels

PASSCAL has both 30 and 65 Watt solar panels available.

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Cables for Multi-Channel Dataloggers

  Channel Type Number of Takeouts Takeout Spacing Total Cable Length Inter Connectable Geode 24ch Single/3-Component 24

Geode Datalogger


System consists of one 24-channel Geodes, with two built-in high-speed connections to interface with other Geodes and a PC-compatible controller or the StrataVisor NZ seismograph.

Suitable for reflection, refraction, downhole, crosshole, surface wave, and tomography surveys, and seismic monitoring.

PH5 vs SEG-Y: Archival Data Format Comparison

PH5, clearly a better choice as an archival data format.



November 1, 2017
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Instrument Use Agreement

Principal Investigator: _________________________


Experiment: ________________


Portable field recording equipment, field computers and other associated equipment purchased by the PASSCAL Program are being made available to the experiment referenced above. In return for the use of this equipment, the Principal Investigator (PI) is expected to adhere to the following conditions with respect to the operation, care and disposition of the equipment and data obtained:

1. Copies of all data sets acquired with the instruments will be made available to the IRIS Data Management Center in accordance with the PASSCAL Data Delivery Policy.

Active Seismic Sources Committee Charge

Charge of the Advisory Committee on PASSCAL Active Seismic Sources

The Incorporated Research Institutes for Seismology (IRIS) currently provides seismic recording instruments to the academic and government seismology research community. Although much of the community’s seismology research is carried out in a “passive” mode of operation, in which researchers are recording seismic signals from natural or ambient seismic sources, a subset of the IRIS community relies on “active” seismic sources in which the researchers generate seismic signals using a variety of mechanical and chemical sources.

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