PASSCAL Seismic Instrumentation Types (Inventory)

This equipment is primarily used in passive networks to record teleseismic signals. The three sensors in the PASSCAL inventory that qualify as broad band sensors are the Streckeisen STS-2, Guralp CMG 3ESP and the Guralp CMG 3T. These sensors have a flat response to ground velocity from 0.0088 Hz, 0.033 Hz and 0.01 Hz to 50 Hz respectively. The recording systems for these sensors are Quantera Q330 and Reftek 130 recording systems. Ancillary equipment used for these types of installations include solar power systems, Argos satellite communication systems, and field computers.

Instruments that fall under this category are used principally for regional seismic arrays or studies around active volcanoes. The sensor used is the Guralp CMG 40T which has a passband from 0.033 Hz to 100 Hz. The recording systems for these sensors are Quantera Q330 and Reftek 130 recording systems. All ancillary equipment used for broadband networks is also available for these installations.

For active source experiments or local high frequency arrays, PASSCAL has available instrumentation classified as short period equipment. The seismometers in our inventory for this purpose are primarily Mark Products L22's and L28's with corner frequencies of 2 Hz and 4.5 Hz respectively. The recording systems for these sensors are Quantera Q330 and Reftek 130 recording systems.

PASSCAL owns numerous sets of spread spectrum radios, repeaters, antennas ,ring buffers, software and computers that are used to convert present recording systems into telemetered seismic networks.

These new single channel recorders are ideal for large crustal scale seismic refraction experiments due to their small size, ease of operation, and low power requirement. However they are also being successfully deployed in high resolution studies that have typically been the realm of cable based recording systems. These instruments are designed to record data in the form of discrete time windows and are timed using GPS time syncs at the beginning and end of deployment. Two sets of single element vertical sensors are available for these data acquisition systems, the Mark Products L40 and the OYO 4.5Hz which have 40 Hz and 4.5 Hz natural periods respectively.

For high resolution imaging studies of the near surface, the PASSCAL inventory includes four sixty-channel Geometrics Stratavisor multichannel recorders. These recorders are used with multple cable types that have varying takeout distances and configurations for three component recording. Two sets of vertical sensors are available for this system, the Mark Products L40 and the OYO GS-11D which have 40 Hz and 4.5 Hz natural periods respectively. Other ancillary equipment for this equipment includes roll-a-long switches and external GPS timing systems.