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Listening with light: MBARI researchers develop innovative new technology for studying the seafloor

Expert Interview

Geo-Sense is a portable instrument for monitoring the seafloor. Distributed acoustic sensing technology turns fiber optic cables into sensors to detect geological processes on the seafloor. Image: Aaron Micallef © 2025 MBARI

Listening with light: MBARI researchers develop innovative new technology for studying the seafloor

MBARI Senior Scientist Aaron Micallef shares how Geo-Sense leverages distributed acoustic sensing technology to transform monitoring of seafloor processes.

Why It Matters

The seafloor plays an important ecological and societal role. Understanding the processes that shape this environment will help guide conservation policy and decision-making about underwater infrastructure and geohazards.

A scientist prepares a scientific instrument in a research lab. The scientist is screwing components onto a silver metal plate on a gray plastic platform inside an open yellow plastic housing. In the background are the black counters, black cabinets, and white walls of a research lab.
Senior Scientist Aaron Micallef leads MBARI’s Seafloor Processes Team, using advanced technology to answer fundamental questions about how the seafloor evolves and functions. Image: Rebecca Englert © 2026 MBARI

MBARI researchers are transforming our understanding of the processes that shape the seafloor. Since the beginning of 2025, a team of MBARI scientists and engineers has been testing Geo-Sense, a new portable instrument that uses distributed acoustic sensing technology for long-term, high-resolution seafloor monitoring. 

Geo-Sense measures the tiny strains and vibrations on a fiber-optic cable laid on the seafloor to track a wide range of processes, from underwater landslides to earthquakes. MBARI researchers recently published a detailed description of this innovative instrument in the journal Scientific Reports, highlighting the remarkable collaboration and expertise that brought it to life.

We sat down with Senior Scientist Aaron Micallef, a marine geologist who leads MBARI’s Seafloor Processes Team, to learn more about this groundbreaking instrument and the data being collected.

Why is Geo-Sense such a big milestone for ocean science?

Two engineers wearing white hard hats and orange life vests collect a yellow fiber-optic cable after recovering a scientific instrument. The cable is tied around a silver cylinder and is wrapped up in a white plastic bin. In the background are maritime equipment and marine operations crew, with blue ocean and blue sky on the horizon.
Fluctuations in laser light along a fiber-optic cable allow scientists to detect earthquakes, landslides, fluid seepage, and other seafloor events. Image: Aaron Micallef © 2026 MBARI

For years, scientists have been trying to collect data to better understand the many active geological processes that shape the seafloor, including earthquakes, underwater landslides, currents, fluid seepage, and volcanic activity. This is challenging because many of these processes happen suddenly, span large areas, or take place when ships and remotely operated vehicles are not present to observe them.

Until now, the scientific community has used fiber sensing of existing telecommunications cables to collect data on past events and then used that data to try to infer what happened. These static cables can provide valuable information, but in most cases, they aren’t located exactly where scientists want to make measurements. We needed to find a way to take the sensor to the geological process rather than waiting for the process to occur near an existing cable.

Geo-Sense was developed to address this challenge, enabling us to place a dense fiber-optic sensor anywhere on the seafloor and continuously monitor data. We can now observe these occurrences in real-time at very fine spatial and temporal scales, determining when they begin, how they evolve, and how they change the submarine landscape over time.

For seafloor science, that’s a major step forward.

Why was MBARI uniquely suited to develop and deploy this instrument?

A scientific instrument with a rectangular silver metal frame, white plastic panels, and a yellow plastic sphere rests on the muddy seafloor. A black cable connected to the instrument extends off-screen toward the camera. In the foreground are the silver metal robotic arm of a deep-sea submersible and a silver fish. The background is greenish-brown mud.
Powerful turbidity currents push sediment down Monterey Bay’s deep submarine canyon, offering MBARI researchers the ideal testbed for Geo-Sense. Image: © 2025 MBARI

Geo-Sense is exactly the kind of project MBARI is built to handle. 

We needed expertise in marine geology, geophysics, fiber-optic sensing, mechanical and electrical engineering, ship operations, and deep-sea deployment. MBARI brings all those capabilities together under one roof and fosters collaboration and innovation among its teams.

We also have Monterey Canyon, one of the most dynamic submarine canyons in the world, on our doorstep, which gave us an ideal natural laboratory for testing whether this technology could detect seafloor processes in a challenging environment.

What has been the biggest challenge in developing Geo-Sense?

Two submersible pilots wearing black microphone headsets operate a deep-sea submersible from a dark control room aboard a research ship. The pilots are seated in large chairs with their backs to the camera. They are watching a wall of monitors displaying video and data feeds from the submersible. The pilot on the right has his right hand on a joystick control.
Development and deployment of Geo-Sense leveraged the expertise of many teams working together, from engineers and machinists to submersible pilots and scientists. Image: Aaron Micallef © 2026 MBARI

We’ve had to overcome many obstacles in developing Geo-Sense, which is true for most efforts to develop groundbreaking technologies. I think our biggest challenge was related to the deployment and recovery of the fiber-optic cable on the seafloor. On paper, that may sound straightforward, but in practice, it was very difficult.

For starters, the cable is one kilometer long. Imagine being on a ship, trying to deploy and then recover a line 11 soccer fields long. The cable also had to be strong enough to withstand the stress of being dragged across the uneven seafloor while remaining sensitive enough to record useful signals. That combination of scientific sensitivity, engineering robustness, and operational practicality was one of the hardest parts of the project. 

MBARI’s engineering and marine operations teams were essential in identifying the right cable, developing the appropriate deployment and recovery strategy, tracking the position and movement of the cable through the water column, and integrating all components into a mechanically robust system that could withstand operations at sea.

What excites you the most about Geo-Sense?

Two members of MBARI’s marine operations crew deploy a scientific instrument from the back deck of a research ship on a bright sunny day. The crew are wearing hard hats and orange life vests. The instrument has a silver metal frame with white plastic shrouds, with two yellow plastic spheres and one silver metal sphere inside. The instrument is suspended from a metal crane outside the frame. In the foreground is the silver metal deck of a research ship. In the background are blue ocean, coastal mountains, and hazy blue sky.
Geo-Sense has the power to transform marine geology by providing researchers with a powerful, portable, and versatile new tool that can be deployed in a variety of locations for high-resolution monitoring of seafloor processes. Image: Aaron Micallef © 2025 MBARI

Geo-Sense lets us observe the seafloor as a dynamic environment. It’s remarkable to collect data from places where the seafloor can change quickly, yet direct observations are rare.

I hope our new paper allows us to share this excitement with a diverse, global community of oceanographers, marine geologists, geophysicists, engineers, hazard scientists, and people working on offshore infrastructure and environmental monitoring. 

I’d like them to take away one main message: portable distributed acoustic sensing is now a realistic tool for ocean science. We’re no longer limited only to existing cables or short-duration ship-based observations. We can begin to design targeted seafloor monitoring experiments around the processes we most want to understand.

What is next for Geo-Sense and your team?

Two members of MBARI’s marine operations crew deploy a scientific instrument over the side of a research ship. The crew are wearing white hard hats and orange life vests. The instrument has a silver metal frame with yellow floats at the top and two silver metal spheres on a green fiberglass grate at the base. The instrument is suspended from a white metal crane at the top of the frame, and the crew are guiding the instrument into the water with ropes. On the left side of the frame is the silver metal deck of a research ship. On the right side of the frame is gray ocean, with overcast gray sky on the horizon.
MBARI engineers continue to refine the design of Geo-Sense for diverse deployment scenarios, including one that is optimized for deployment with a remotely operated vehicle. Image: Marike Pinsonneault © 2026 MBARI

Our next adventure will be deploying Geo-Sense to monitor activity at the Kolumbo submarine volcano in the Mediterranean Sea later this year. It will be an exciting project because volcanic systems are dynamic, hazardous, and difficult to monitor at high resolution on the seafloor.

Our long-term goal is to develop flexible platforms with distributed acoustic sensing technology that can be rapidly deployed in diverse environments—from deep-sea canyons to Arctic fjords—to monitor geohazards, seafloor processes, and environmental change. We’ll continue to share our findings with our peers and collaborate with others to move this body of work forward. 

This technology is a game-changer for marine geology, helping us better understand the processes that shape the seafloor. Data from Geo-Sense will provide resource managers and policymakers with the information they need to make informed decisions about marine protected areas, underwater infrastructure, and coastal geohazards.

Development of Geo-Sense was made possible by the David and Lucile Packard Foundation and its longtime support of MBARI’s work to advance marine science and engineering to understand our changing ocean.

Research Publication:

Micallef, A., A. Sherman, P. McGill, A. Schnittger, R. Englert, D. Klimov, B. Touryan-Schaefer, R. Henthorn, D. Hill, S. Jacobs, C.K. Paull, R. Gwiazda, A. Verma, and A. Goyal. 2026. Geo-Sense: A portable Distributed Acoustic Sensing (DAS) system for high-resolution seafloor monitoring. Scientific Reports. https://doi.org/10.1038/s41598-026-55260-y

For additional information or images relating to this article, please email pressroom@mbari.org.

MBARI Team

Paul McGill

Senior Electrical Engineer

External Collaborators

David Hill, Steve Jacobs – SINTELA
Ayush Goyal, Ankur Verma – Lightscline

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