Rare ADCP deployment during a tsunami provides insight into interactions of tsunamis, rivers and tides

On July 29, 2025, a powerful earthquake struck the Kamchatka peninsula in eastern Russia. With a moment magnitude (Mw) of 8.8, the earthquake ranks among the six most powerful earthquakes ever recorded. The event generated widespread concern across the Pacific Basin, prompting tsunami warnings and preparedness measures in several countries, including coastal regions of Chile.

Just hours before the earthquake, San Diego State University assistant professor Dr. Ignacio Sepúlveda met with Innovex engineers Jorge Santamarina and Nicolás Donoso in Valdivia, Chile to discuss potential collaboration between the organizations, agreeing they could mutually benefit from sharing data collected by Innovex in the Valdivia River during equipment testing. When the news of the earthquake broke, Dr. Sepúlveda called back with a proposition: would it be possible to gather in-situ measurements of currents in the river as the predicted tsunami struck?

Moving quickly to deploy an ADCP before the tsunami

Dr. Sepúlveda and Donoso worked quickly to coordinate with the Valdivia Yacht Club, and shortly afterwards the team was on a boat to deploy their measurement equipment. Innovex had a Nortek Eco ADCP on-hand already, which proved convenient for its quick and simple setup in a time-limited situation.

“We only used a smartphone to configure the ADCP and the release mechanism, and it took us less than 45 minutes to have the system ready for deployment,” says Donoso of using the Eco ADCP. “I found the Eco to be a fantastic and very well-designed instrument. Its simplicity made it possible to deploy it under conditions that required a very fast setup.”

Deploying an ADCP before a hazardous event like a tsunami involves risks, so the team relied on Dr. Sepúlveda’s previous models of the area to choose an optimal location where they anticipated they could capture the effects of the tsunami without the currents becoming strong enough to sweep away their anchored system.

Gathering in-situ current measurements in a river during the tsunami

Just 18 hours after the earthquake hit Russia, around 2pm local time in Valdivia, the team deployed the Eco ADCP at 9m depth in the Valdivia River using the Nortek Eco buoy system with a timed release. They attached 60 kg of ballast to protect from the extreme conditions the system might encounter and set the Eco to provide measurements in two-minute intervals for the duration of the four-day deployment. 

The quick deployment allowed the team to evacuate the area by 3:30 pm local time, with around two hours to spare before the anticipated tsunami arrival based on Dr. Sepúlveda’s models. 

The team retrieved the Eco four days later and downloaded the data using the Eco WebApp. The data showed variations in water levels and current velocities, revealing the disturbances caused by the tsunami.

The team correlated the data from the Eco with a nearby coastal tide gauge station and concluded the tsunami wave took approximately 20 minutes to propagate upstream to the location of the ADCP measurements. 

“The maximum amplitude of the oscillation was observed about four hours after the initial tsunami arrival, reaching values on the order of tens of centimeters,” says Donoso. 

While the maximum impact was a few hours after the tsunami arrival, the data showed that the hydrodynamic response of the river persisted for two to three days.

“Using wavelet analysis, we noted that the tsunami energy, initially distributed across multiple periods, evolved into dominant components with periods of approximately 30 and 100 minutes,” explains Sepúlveda.

Improving tsunami hazard assessments

Measuring currents in a river during a tsunami may seem counterintuitive, but understanding the interactions between local waters and the tsunami is important to predicting the tsunami’s impacts on the area. 

“For a long time, the tsunami science community has known that coastal responses of tsunamis are highly influenced by local conditions, like tide and rivers,” says Dr. Sepúlveda. “These two coastal processes, present every day, can severely condition the tsunami inundation and damage.”

However, Dr. Sepúlveda explains, these interactions between tsunamis, rivers and tides have rarely been measured in real life.

“Besides a measurement done in the Columbia River in the US after the 2011 Japan earthquake, this was a very unique measurement,” he says.

Having in-situ measurements like those gathered by this team not only requires rare environmental conditions, but also the ability to act quickly and deploy in a short time period. The team’s fast actions enabled one of the only in-situ measurements of currents in a river during a tsunami event. 

Strengthening understanding of the interactions between rivers, tides and tsunamis

Having insight from real-life data is crucial to creating accurate models, which will be used to predict the impacts of future tsunamis. Coastal areas rely on these predictions when hazards occur to inform protection measures and evacuations. 

“This measurement will be critical to calibrate new models that can simulate the coupled interaction of tsunami, tides and rivers,” says Dr. Sepúlveda. “Ultimately, the measurement and scientific effort will help the tsunami community to improve our tsunami hazard assessments in estuarine areas worldwide.”

Future monitoring and collaboration

As a result of this collaboration, two permanent monitoring stations have been deployed in the Valdivia River Estuary.

“These stations continuously measure water levels, temperature, oxygen, and salinity using sensors designed and manufactured locally in Valdivia, Chile — something we are very proud of,” says Donoso.

Donoso adds that the experience of deploying the Eco on such a short time scale and gathering such important results also improved the team’s technical and operational capabilities as well as their collaboration.

“Today, we are better prepared to rapidly deploy instruments and collect high-quality in-situ data during extreme events such as tsunamis and other coastal hazards,” says Donoso. “What began as an urgent, improvised response has evolved into a long-term monitoring and scientific collaboration that improves our readiness, resilience, and contribution to understanding complex coastal systems.”