Google’s Undersea Cables Can Detect Earthquakes: Here’s how

by Drishti Ranjan
Google’s Undersea Cables Can Detect Earthquakes: Here’s how

March 11, 2021

Can earthquakes be detected with submarine cables? The future may be here! Google claims that the subsea fiber optic cables it has laid down can be used as earthquake and tsunami warning systems around the globe. More than 3,000 miles of transatlantic undersea cables are being planned to be laid by 2022. So it looks like we’re just getting started!

Hopper Joins Curie, Dunant and Equiano

YaleNews hopper grace.UNIVAC.102635875 CC 0

This new undersea cable project is named after the American scientist Grace Hopper. Grace Brewster Murray Hopper was a pioneering computer scientist who is famous for developing an early computer system which was essential in the development of Common Business-Oriented Language OR COBOL. Google announced that it will name the subsea cable after Hopper to honour his contribution.

It will be the first new fiber cable that links the US with the UK, since 2003. Google already has three privately-owned undersea cables: Curie, Dunant and Equiano. Hopper is being used to join existing subsea cables like Google’s Curie, which will be the first cable laid between Los Angeles and Valparasio. Dunant, on the other hand, stretches from USA to France. While Equiano connects Portugal to Cape town, South Africa.

Google More Promising Than Microsoft, Facebook?

The Hopper subsea cable will be accommodated with 16 fiber pairs, which Google considers to be a ‘significant upgrade’ to the existing mechanism in place. These cables will have the capacity of 340-350tbps. A similar project had been undertaken to connect Spain and America by the MAREA cable in 2018, which was the joint venture of Microsoft, Facebook, and Spain’s Telefonica. However, in comparison to MAREA, which was jointly held and provided only 200 Tbps; Hopper, owned purely by Google seems much more promising.

interview te subcom strieves towards new acheivements

“Grace Hopper will incorporate novel optical fiber switching that allows for increased reliability in global communications, enabling us to better move traffic around outages,"

- Google

How Will These Cables Detect Earthquakes?

In a recent press release, Google stated how after an experiment involving one of their subsea cables, they concluded that it might be possible to use those as a warning system to predict earthquakes and tsunamis around the world.

Apart from faster data transmission, Google claims that it’s private subsea cable infrastructure, which has been toyed with, in attempts to detect seismic data, since 2018, finally demonstrates how exactly this can happen. Earlier, these experiments that required special sensing fiber had proven effective over distances of up to 100km. Meanwhile, now it seems that this capacity has been extended to tens of thousands of kilometres!

The most surprising element is the fact that experiments to detect seismic activities used to require extra equipment, but this advancement uses the existing cable network in place. This is facilitated by the cable’s property to carry data as pulses of light at 204,190 kilometres per second. The light gets distorted while travelling and upon arriving, meets light pulses at the receiving end where the distortion is corrected by digital signal processing. One of the properties of light that is tracked as part of the optical transmission is the state of polarization (SOP). The SOP changes in response to mechanical disturbances along the cable and tracking these disturbances enables us to detect seismic activity.   

How Did Google Start Tracking The Disturbances?

In 2019, Google began to track disturbances in the ocean bed, with the aim of finding spectral signatures of seismic activity. However, the first earthquake detected by it happened in late January 2020, where an earthquake of 7.7 magnitude hit the country of Jamaica; which was 1,500 km away from the nearest cable! After this incident scientists were able to validate their observations with established seismic monitoring stations.

Upon analysing the data Google revealed, it can be concluded that earthquakes getting emanated from tectonic plates aren’t the only ones that can be detected, but also the pressure changes in the ocean bed, which can help with predicting tsunamis as well.

In case Google somehow converts it’s demonstration into a complete working mechanism, it could prove it’s significant contribution in tsunami detection. If that happens, it would revolutionarily change the way tsunamis affect human settlements. 


According to Google, most seismic activity detection equipment in the ocean bed is either scattered throughout, or set on shore. Detection by the former device doesn’t contribute much to mitigate risks as it doesn’t have an early detection which can give people enough time to evacuate; whereas for the latter, it is limited to the speed of travelling wave. 

However, in case the epicentre is near one of the cables, a tsunami warning system that facilitates data transmission at the speed of light could communicate a warning to mitigate risks to human lives by a huge time margin.


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