Rotational Seismometers

Measure earth motions as never before...            

ATA’s new SMHD sensors measure earth’s rotational seismic motion in the field with a precision previously available only by building dedicated scientific observatories.  

What is rotational seismology? Seismic waves travel through the earth, translating and rotating the ground as they pass. For the past century, seismic measurements focused on translation (using devices such as geophones) and ignored rotation. Recent studies suggest that rotational motion can be significant and encodes important information about the earth and the seismic event.  

Magnetohydrodynamic Angular Rate Sensors
Earth Motion Includes Three Translation and Three Rotation Components

Adding ATA’s rotational sensors provides direct measurement of the full state of the seismic wave. These measurements enable novel techniques for discriminating shear waves from pressure waves, measuring shear wave velocity at a single station, increasing effective sampling in seismic sensor arrays, and quantifying earthquake hazard due to rotational motion. Potential uses include: earth surface, underwater, and downhole seismic measurements; micro-seismic event monitoring and civil engineering for hazard characterization.

What are ATA’s new Proto-SMHD sensors? ATA’s new seismic sensors measure rotation directly and remain insensitive to translation. They produce a signal proportional to angular rate of motion. Compared to alternative technologies, they are simple, rugged, consistent from unit to unit, and provide high sensitivity, high dynamic range, and a low noise floor at mid to high frequencies. No other portable instrument provides better performance over the 0.3 to 100 Hz frequency band. At the current time, ATA is offering prototype units to assess market interest and enable exploratory investigations. Click on the pictures below to link to datasheets for the Proto-SMHD single-axis sensor and the Proto-SMHD Triad Box, which is suitable for field deployments.

Click here for the Single-Axis Proto-SMHD Datasheet

Click here for the 3-Axis
Proto-SMHD Datasheet

ATA's Proto-SMHD Triad Box
Being Installed in the Field