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Guralp Stratis - a Commercial 6 Degree of Freedom Seismometer for Academic and Research Applications

Description: 

Traditional research grade 3-component seismic sensors by their very design are sensitive to both translational ground movement as well as rotational (or tilt) motion. This is most prevalent in the horizontal components of sensors which are most sensitive to tilt of the ground. The outputs of traditional seismometers represent a sum of rotation and displacement information. Most applications processing the data make the assumption that the outputs are proportional to purely displacement although this is not strictly the case in commercial devices.

New technologies are now allowing for accurate and precise discrimination between the two components which make up the vast majority of seismic records.

Stratis is the world’s first integrated seismic sensor offering simultaneous output of both rotational and displacement data in all 3 axis. Stratis offers six concurrent outputs providing Z, N and E ground displacement channels proportional to velocity (Metres/second) and rotation channels in the Z, N and E planes proportional to velocity in rotation (Radians/Second). The provision of the measurement of the six degree of freedom now permits derivation of the Elasticity Tensor from a single sensor.

The Stratis displacement output removes these rotation effects and gives a ‘pure’ displacement measurement. This is unique in the seismic sensor marketplace, providing true displacement data that is uncontaminated by rotational signals. This will therefore allow for higher fidelity seismic measurements, improving our analysis and understanding of earthquake processes.

These six parameters are measured at a single point in the geometric center of the sensor. Use of multiple separated sensors to derive rotation can only approximate true rotation at the same point as displacement. By integrating these measurements into a single instrument, the installation process is also greatly simplified thereby enabling wider access to rotational seismic data. Naturally, the separation of rotational information from the displacement outputs also gives a pure displacement sensor – something unique for the seismological community.

Session: Fifty Years and Beyond of Broadband Seismic Instrumentation: Performance, Precision and Uncertainties [Poster]

Type: Poster

Date: 4/16/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: James

Student Presenter: No

Invited Presentation: 

Poster Number: 139

Authors