The 8.8 magnitude earthquake off the coast of Russia’s Kamchatka Peninsula generated water waves traveling at jetliner speeds toward Hawaii, California, and Washington states on Wednesday.
Yet, when the tsunami reached the U.S., it appears not to have inflicted widespread devastation, with some areas where warnings were issued showing no signs of significant flooding.
This doesn’t mean the tsunami was a “bust” or poorly predicted, according to earthquake and tsunami researchers.
“When you hear ‘tsunami warning,’ people often think of dramatic scenes from movies, and when it arrives at just three feet, they might wonder, ‘What’s going on?’,” remarked Harold Tobin, director of the Pacific Northwest Earthquake Network and professor at the University of Washington. “We should view this as a success; we received a warning, but the situation wasn’t catastrophic.”
Here’s what you should know.
How intense was the Kamchatka earthquake? What caused the initial discrepancies?
Initially, the US Geological Survey assessed the Kamchatka earthquake at magnitude 8.0, which was later adjusted to 8.8.
“It’s not unusual for major earthquakes to see such adjustments in the first moments,” Tobin explained. “Our standard methods for calculating earthquake sizes can quickly saturate, akin to turning up the volume on a speaker until it distorts.
A buoy measuring the quake, located approximately 275 miles southeast of the Kamchatka Peninsula, gave the first signs of the earthquake, showing bigger waves than the initial report.
This buoy belongs to the National Oceanic and Atmospheric Administration’s DART (Deep Ocean Assessment and Reporting) system and is connected to a submarine pressure sensor roughly four miles deep.
That sensor detected waves measuring 90 centimeters (over 35 inches), which caught the attention of tsunami researchers.
Vasily Titov, a senior tsunami modeler at NOAA’s Pacific Ocean Environment Research Institute, noted:
Titov reflected on the 2011 Tohoku earthquake and tsunami, which tragically claimed nearly 16,000 lives in Japan.
Subsequent earthquake models confirmed the Wednesday earthquake’s magnitude as 8.8, as detailed by the USGS calculator.
In comparison, Tohoku was significantly larger.
Tobin estimated that the energy released during the Kamchatka quake was two to three times less than that in Japan, with the tsunami generated there being approximately three times as severe.
He further noted that the Tohoku event “created a notably large seafloor displacement.”
Tobin speculated that the Kamchatka quake likely had less seafloor displacement than what could occur in a worst-case 8.8 scenario, though more research is needed for substantiation.
How did researchers generate predictions? How accurate were they?
Within two hours, researchers produced tsunami predictions for various “warning points” along both the Pacific and US coasts, forecasting tidal gauge and flood levels.
The tsunami took around eight hours to reach Hawaii and twelve hours to arrive at the California coast.
Titov, who assisted in developing the model used by predictors in the National Tsunami Warning Centers in Hawaii and Alaska, explained that the model relies on seismic data and a network of over 70 DART buoys along the Pacific edge. The U.S. operates more than half of these buoys.
Titov indicated that the model projected tsunami waves hitting Hawaii’s North Shore region at approximately two meters.
“Hawaii was predicted to have waves of about 2 meters [6.5 feet], and actual measurements were around 150 centimeters, or 1.5 meters (5 feet). That aligns perfectly with our expectations,” Titov stated.
A similar trend was observed in parts of California, according to Titov.
As assessments of flooding continue to come in, it takes time to determine how well the model performed.
“We know there were floods in Hawaii. We can’t ascertain the full extent yet, but initial reports seem to align closely with our predictions,” Titov shared.
Why did residents in Hawaii evacuate for a 5-foot wave?
Yong Wei, a tsunami modeler and senior research scientist at the University of Washington and NOAA’s tsunami research center, indicated that 1.5 meters (5 feet) of tsunami waves could be highly perilous, particularly in Hawaii’s shallow waters.
Tsunami waves carry significantly more energy than typical wind-driven waves, possessing shorter wavelengths and durations between waves, resulting in slower speeds.
Wei noted that tsunami waves of this stature could surge several meters inland, producing hazardous currents and endangering boats and other objects.
“People can get hurt. If you ignore the warning and stay, even a wave of two meters can be deadly,” Wei warned. “Being on the beach can expose you to powerful currents that may pull you into the ocean, which can lead to fatalities.”
Tobin expressed that he viewed the initial warning as conservative yet necessary.
“It’s essential not to belittle warnings. If nothing happens, people shouldn’t think, ‘Oh, we had alerts and nothing transpired.’ Warnings need to be cautious, allowing for some margin of error.”
Was this a significant event?
No. The Kamchatka Peninsula has a long history of seismic activity.
“This area has been slated for another earthquake, with several occurring recently, which indicates a heightened risk,” researchers noted.
In 1952, prior to a robust understanding of plate tectonics, a 9.0 magnitude quake struck the Kamchatka Peninsula in a similar location, resulting in a tsunami that impacted the town of Severokrilsk.
“The Russian populace was caught off guard. It was an immensely powerful quake, leading to a massive tsunami, and they were unprepared,” McInnes shared.
McInnes explained that the tsunami measured between 30 to 60 feet in height in the southern section of the peninsula.
“Thousands perished, and the town suffered considerable destruction,” stated Joanne Bourgeois, a professor emeritus of sedimentology at the University of Washington.
How will the tsunami warning system function if an earthquake threatens your area?
The Kamchatka tsunami arose from a massive earthquake along a subduction zone fault, where one tectonic plate is pushed below another. A comparable fault exists offshore the U.S. West Coast, known as the Cascadia Subduction Zone, stretching from Northern California to Northern Vancouver Island.
“It’s akin to a mirrored image of the Pacific Ocean,” remarked Tobin. “The relatively shallow depth of 8.8 in Cascadia is certainly plausible for a scenario here.”
In fact, Cascadia has the potential to produce significantly larger earthquakes, as modeling suggests it could generate tsunami waves reaching heights of 100 feet.
Typically, earthquakes in subduction zones yield tsunamis that reach the coast within 30 minutes to an hour, and predictions are developing better methods for estimating tsunami impacts along the U.S. West Coast before flooding occurs.
Titov emphasized that enhancing predictions will necessitate advancements in underwater sensors, improved computing infrastructure, and AI algorithms.
Tobin noted that the success of Tuesday’s tsunami warning should inspire more investments in underwater sensors and earthquake monitoring stations along the subduction zones.
“This incident highlights the significant role of NOAA and USGS. Many questioned these agencies’ relevance, but without NOAA, no alert would have been issued. The next warning could be for a more imminent threat. They truly demonstrated their importance,” he asserted.
Source: www.nbcnews.com
