Welcome to the Silicon Audio Newsletter!

Silicon Audio is starting a newsletter to keep customers up to date on the latest engineering challenges we face as well as getting further insight into the brains of the company. To kick things off, let’s explore a commonly received question: Why the name Silicon “Audio” Seismic? 

Silicon Audio began operations in 2009 making high-SNR MEMS microphones for consumer electronics while using a compact embodiment of the optical interferometer used in Silicon Audio’s seismic sensor today. By 2012, Silicon Audio had partnered with a market-leading smartphone OEM and MEMS microphone chip maker.  In a 2013 pilot manufacture, the best-in-class SNR was successfully created  The microphone, however, had an Achille’s heel. Operating in open-loop, the intrinsic dynamic range was limited to 100 dB, and the product was difficult to manufacture. 

While working on the microphone, The Department of Energy asked Silicon Audio if the low-noise optical read-out technology could be used to measure seismic signals to listen for nuclear explosions anywhere in the world. Around the same time, the oil and gas industry asked if the sensor could be used for seafloor seismic exploration and beat the low-frequency performance of common geophones. This led to an evolution of products to address hi-fi seismic. Silicon Audio’s engineers borrowed tried-and-true design features of the workhorse geophone and added low-noise optical readout. The moving element of the seismometer was now equipped with a strong, linear coil-magnet actuator.  When combined with interferometric detection and low noise electronics, a closed-loop, force-balanced sensor was born.  

Fast forward and Silicon Audio has built high-fidelity seismometers for dam monitoring, volcano monitoring, and deep bore-hole deployments over 1 km beneath the surface. A recent project has been building space-ready sensors to survive shuttle launch and land on the moon. As the genesis seismic application was oil and gas, the product was designed from the very beginning for high shock tolerance and rough handling.  The sky’s the limit with what these sensors can do and Silicon Audio is glad to have you on this journey.


Group photo of the Silicon Audio team

Cheers from the Silicon Audio team!

AGU Poster Cascadia Borehole

This poster shows a comparison of 1000 ft deep borehole Silicon Audio 203-60 sensor with geophones and a fiber distributed acoustic sensor (DAS).

We especially liked the quote below:

For microearthquakes, assuming frequency range of above 2 Hz, the SA-ULN sensor would be the ideal choice.

Correa, et al. (2020) Exploring the limits of fiber-optic sensing in Cascadia: Borehole passive seismic monitoring using co-located DAS, low noise optical accelerometers, and geophones, Abstract 759800

AGU Fall Meeting 2020 (confex.com)https://agu.confex.com/agu/fm20/meetingapp.cgi/Paper/759800

AGU Poster for SIIOS

Check out the AGU poster for one of the projects we are working on for NASA.

The Seismometer to Investigate Ice and Ocean Structure (SIIOS) project is advancing the maturity of a commercial off the shelf (COTS) optical seismic sensor for spaceflight. The primary mission targets for SIIOS include landed spacecraft sent to the icy satellites in the outer solar system, including Europa. SIIOS will provide direct geophysical measurements that probe planetary ice-shell and ocean layers by exploiting terrestrially demonstrated methods. In terrestrial settings, active and passive seismic studies are used to measure ice thicknesses and to determine the nature of sub-glacial materials. Seismic surveys can also inform the vertical temperature distribution within ice, an important property for tidally heated icy worlds.

The COTS instrument has been deployed and successfully operated in analog environments in the terrestrial cryosphere. Qualification for spaceflight, however, requires electronics upgrades, specifically to the commercial-grade control/conditioning electronics mounted in the sensor. We are also seeking to improve the sensitivity of the seismometer by lowering its noise floor. Here we present the upgraded capabilities of the SIIOS instrument. We also describe the work performed to advance the device to TRL 6 under NASA’s Instrument Concepts for Europa Exploration (ICEE) 2 program.

P044-0018 – The Seismometer to Investigate Ice and Ocean Structure (SIIOS)

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