Page 24: of Marine Technology Magazine (January 2026)

FEATURE GNSS-A SEAFLOOR MONITORING

The USGS Wave

Glider on mission equipped with

Sonardyne GNSS-A instrumentation.

MONITORING THE RESTLESS

EARTH FOR THE NEXT “BIG ONE”

By Michelle Barnett, Ocean Science Business

Development Manager at Sonardyne hen the 8.2 magnitude Chignik earth- tween underwater technology company Sonardyne, Scripps quake hit off the coast of Alaska in Institution of Oceanography and the U.S. Geological Survey 2021, it was a big warning signal. The (USGS), the ability to remotely monitor our restless earth is largest earthquake in the US since 1965 not just possible but also becoming standard practice.

W and one of the largest globally in recent Using a technique called GNSS-A, an increasing amount of years; it was a reminder of the geohazards lurking, out of coastline most vulnerable to earthquake and tsunami hazards, sight, off our coastlines. including the US Paci? c Coast, is being monitored.

Offshore events like these could trigger a tsunami, putting

What is GNSS-A? major coastal cities and regions at risk.

But, until recently, the geological activity that leads to an GNSS-A works by combining satellite positioning with un- earthquake like Chignik was a signi? cant blind spot to scien- derwater acoustics to track sea? oor movement with centime- tists, lying hidden and inaccessible beneath the waves. ter-level accuracy. An uncrewed surface vessel (USV) with

Now, thanks to ongoing collaboration and development be- Sonardyne’s GNSS-A payload patrols above an array of So- 24 January/February 2026

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