The Gecko Prism is our an integrated sensor and recorder unit. The sensor uses the latest in optical interferometry technology, allowing for a compact and robust sensor. The Prism is available in there variants with velocity output: short period Prism-SP (10-seconds to 150Hz), or the more sensitive middle-period Prism-MP (40-seconds to 90Hz) and long period Prism-LP (120-seconds to 60Hz). With low latency long period phase response, the velocity Prism-MP and LP have noise levels below the NLNM between 1 and 10 second periods. The Prism is well suited to most quiet-to-moderate noise stations, and perfectly suited to portable and surface installations.
The Prism-SP 10-second period sensor uses omnidirectional components, so the sensor can be installed at any tilt angle with loss of monitoring range.
The Prism-MP and -LP models are also very tilt-tolerant, able to operate at installation angles of up to 15 degrees from horizontal. As with all broadband seismometers with high velocity 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.