The Cooperative Institute for Climate, Ocean, and Ecosystem Studies

By Evan Bush, NBC News

The magnitude-8.8 earthquake off Russia’s Kamchatka peninsula sent a wave of water racing at the speed of a jetliner toward Hawaii, California and Washington state, spurring warnings and alarm overnight Wednesday.

But when the tsunami waves arrived, they didn’t cause devastation or deaths in the United States, and the inundation might not have appeared threatening in some locations where warnings were issued.

That doesn’t mean the tsunami was a “bust,” that it was poorly forecast or that it didn’t pose a risk, earthquake and tsunami researchers said.

“You start to hear ‘tsunami warning,’ and everyone immediately thinks of the last Hollywood movie they saw, and then it comes in at 3 feet and people are like, ‘What’s that?’” said Harold Tobin, the director of the Pacific Northwest Seismic Network and a professor at the University of Washington. “We should count it as a win that a tsunami occurred, we got a warning and it wasn’t the worst-case scenario.”

Here’s what to know.

How strong was the Kamchatka earthquake? And why did it change so much?

Initial reports from the U.S. Geological Survey pegged the Kamchatka earthquake at magnitude 8.0. Later, it was upgraded to 8.8.

“That is not uncommon for very, very large earthquakes in those initial minutes,” Tobin said. “Our standard algorithms for determining the size of an earthquake quickly saturate. It’s like turning up an amp and getting a lot of distortion.”

One of the first signs the earthquake was stronger than the initial seismic reports said was an initial measurement from a buoy about 275 miles southeast of the Kamchatka peninsula.

The buoy, which is part of the National Oceanographic and Atmospheric Administration’s DART (Deep-ocean Assessment and Reporting of Tsunamis) system, is connected to a seafloor pressure sensor about 4 miles below the surface.

The sensor registered a 90-centimeter wave — more than 35 inches — which is eye-popping to tsunami researchers.

“That’s the second-largest recording we ever saw in the tsunami world,” said Vasily Titov, a senior tsunami modeler at NOAA’s Pacific Marine Environmental Laboratory, adding that it indicated there was “a catastrophic tsunami propagating in the ocean.”

Titov said the only higher reading was from the 2011 Tōhoku earthquake and tsunami, which killed nearly 16,000 people in Japan.

Seismic models later confirmed that Wednesday’s earthquake was magnitude 8.8, which means it released nearly 16 times as much energy as a magnitude-8.0 earthquake, according to a USGS calculation tool.

Tōhoku was much bigger.

Tobin estimated that earthquake released two to three times as much energy as was observed in Kamchatka. Titov said the tsunami in Japan was also about three times larger.

In addition, he said the Tōhoku earthquake “produced an anomalously large seafloor displacement,” lurching and moving more water than expected, even for an earthquake of its magnitude.

At Kamchatka, “it’s likely that there was less seafloor displacement than could have happened in a worst-case or more dire scenario for a magnitude-8.8,” Tobin said, though more research will be needed to confirm that theory.

[…]

Why were people in Hawaii evacuated for a 5-foot wave?

Yong Wei, a tsunami modeler and senior research scientist at the University of Washington and the NOAA Center for Tsunami Research, said a 1.5-meter (5-foot) tsunami wave can be very dangerous, particularly in shallow waters off Hawaii.

Tsunami waves contain far more energy than wind waves, which are far shorter in wavelength and period (time between waves) and slower in speed.

Wei said tsunami waves of the size that struck Hawaii can surge inland “tens of meters,” produce dangerous currents and damage boats and other moveable objects.

“People die. If they stay there and they don’t get any warning, 2 meters can definitely kill people,” Wei said. “If you’re on the beach, strong currents can definitely pull you out into the ocean and people will get drowned.”

Tobin said the initial warnings were conservative but appropriate, in his view.

“I don’t want people to think, oh, we had a warning and nothing much happened and pooh-pooh it — ‘I can ignore it,’” he said. “Warnings by nature have to err a bit on the side of caution.”

…

Read more about CICOES research on tsunami forecasts and modeling.

By Monica Allen, NOAA

Ice forecasts would boost public safety, subsistence fishing, hunting, transportation and commerce

NOAA and the University of Washington have joined with the Native Village of Kotzebue, Alaska, to create a new forecast model that will help predict the spring ice breakup on a major lake outside the village.

Hotham Inlet, known locally as Kobuk Lake, is a 38-mile-long, 19-mile-wide lake that transforms each fall when the ice freezes into a prime place for fishing and a critical travel corridor for people on snowmachines and with dog teams.

The lake is a few miles from Kotzebue, the largest community and the economic and transportation hub in Alaska’s Northwest Arctic Borough. The iced-over lake allows local communities to create an ice road to transport air freight that arrives in Kotzebue to communities around the lake, visit friends and make it easier for people from smaller villages to get to Kotzebue for shopping.

While NOAA National Weather Service ice forecasts provide information about ocean and coastal sea ice and ice breakups on major rivers, there are no specialized forecast models for Alaskan lakes, even large ones like Kobuk Lake, which is fed by two rivers and influenced by tidal flow from the Chukchi Sea.

“This new model we are developing is the future of ice prediction,” said Jiaxu Zhang, the project leader who is a research scientist at the UW’s Cooperative Institute for Climate, Ocean and Ecosystem Studies and NOAA’s Pacific Marine Environmental Laboratory in Seattle. “We want to make it useful and relevant to the people who depend on knowing the condition of ice for safe fishing, hunting, transportation and trade. And the best way to do that is to work directly with the people of Kotzebue on it.”

Unlike traditional ice models that treat ice as one continuous sheet, this new model will simulate how individual ice floes crack, move and pile up — complex processes that are key to predicting exactly when and where Kobuk Lake ice will break up.

For thousands of years, the community has used its Indigenous knowledge and deep understanding of ice to plan their fishing and hunting. But with changing temperatures and weather, this new model which combines physical science with Indigenous knowledge could improve the forecasting of spring breakup for Kotzebue and become a model for other Alaskan and Arctic locations.

The residents of Kotzebue bring valuable knowledge of the ice, the wildlife that inhabit it and the ways they have detected when the breakup is occurring in the past.

Ice fishing provides major source of protein for locals

“Fishing here is really important for us,” said Bobby Schaeffer, an elder from Kotzebue who contributes to the project. For Schaeffer and many of his neighbors, much of their protein comes from subsistence fishing and hunting.

Kobuk Lake is well known for a large whitefish called sheefish that can grow as large as 50 pounds. Community members also fish for herring and a variety of smaller whitefish species. These fish are then frozen, pickled or dried to be consumed throughout the year.

The ice fishing season typically begins in late fall and continues into May. In recent years, the ice in parts of the lake has broken up earlier than it did 20 or more years ago, said Schaeffer. He attributes it to the warming atmosphere, which is affecting not only the ice formation and thickness, but all the fish migration patterns, birds, seals and caribou that depend on the lake’s ecosystem.

Team gathers aerial and on-ice observations for model

To create the model, Zhang and her interdisciplinary team collected observations of the ice before and during breakup, including aerial surveys from a NOAA Twin Otter airplane operated by NOAA Commissioned Corps officers and crew. In May, the aircraft was loaded with sensors to take high-resolution images and LIDAR (Light Detection And Ranging), a remote-sensing method that uses laser light to measure distances and create highly detailed 3D representations of ice thickness, surface roughness, and environmental features.

In addition to the aerial observations, Schaeffer and Alex Whiting, the Native Village of Kotzebue environmental program director, collected observations on the ground and on the ice. Schaeffer measured the thickness of the ice over time by drilling holes in strategic locations on the ice. Tyler Kramer, a Kotzebue high school student, monitored the salinity of the water flowing into the lake from the Chukchi Sea. By understanding how much salt water flows into the lake and how much of the colder fresh water from rivers blocks that salt water flow into the lake, the scientists have key information for the model about how the warmer saltier water accelerates ice melting from below.

The Kotzebue community members have also contributed a wealth of information about how the breakup has occurred in past years, areas where it is likely to soften first and areas where ice may support fishing and hunting longer into the spring before it breaks up.

Two interesting focal points of the research are the formation of annual pressure ridges running across the lake and recurring thin ice areas that melt out early in the breakup process.  While the location of these open water areas reappear in the same place each year, the position of the associated cracks can change from year to year, according to an analysis of satellite images and the current observations. Understanding the forces that cause these phenomena will help to create a successful and accurate breakup model.

The next step to building a model is to create what’s called a hindcast, a validation technique that involves running historical observations through the model and comparing the accuracy of the output to the actual timing of past ice breakups. From this, the team will create and test a model to predict future ice breakup.