Prism Broadband Seismograph

The ESS Prism is our first broadband seismometer, available as a stand-alone sensor for connection to any seismic recorder, or as a convenient integrated sensor and recorder unit – the Gecko Prism. The sensor uses the latest in optical interferometry technology, allowing for a compact and robust sensor that is only 125mm in diameter and under 100mm high. The Prism is available in either 40-second to 90Hz or 120-second to 40Hz bandwidths, and is the perfect low cost alternative to traditional mass-based sensors. With better long period phase response than traditional feedback sensors, the Prism has noise levels below the NLNM between 1 and 10 second periods, the sensor is well suited to most quiet-to-moderate noise stations, and perfectly suited to portable and surface installations.

Description

The Prism’s optical feedback circuitry is also very tilt-tolerant, able to operate at installation angles of up to 15 degrees from horizontal. The self-levelling technology makes a bubble spirit level redundant. As with all broadband seismometers with such high sensitivity, an insulation cover is recommended to reduce thermal currents that affect sensor drift. With such a small package to cover, a small foam box or a thermal mass such as a hollow concrete block filled with sand will provide the additional stability, particularly when installed in underground vaults as shown the the video below.

See our Support page to download the product manual.

Data Sheets: Prism Seismometer, Gecko Prism Seismograph

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