Minimal U.S. effects from tsunami don’t mean the forecast was inaccurate

The earthquake of magnitude 8.8 off the coast of the Kamchatka peninsula in Russia sent a wave of water races at the speed of an airliner to Hawaii, California and the state of Washington, arousing warnings and alarms overnight.

But when the waves of tsunami arrived, they did not cause devastation or death in the United States and the flood may not have seemed threatening in certain places where warnings have been issued.

This does not mean that the tsunami was a “bust”, that it was poorly forecast or that it did not put risks, researchers of earthquake and tsunami.

“You start to hear a warning from Tsunami and everyone immediately thinks of the last Hollywood film they saw, then he’s at 3 feet and people are like” what is it? “” Said Harold Tobin, director of the northwest Pacific seismic network and professor at Washington University. “We have to count as a victory that a tsunami has occurred, we had a warning and it was not the worst case.”

Here’s what you need to know.

What was the strength of the Kamchatka earthquake? And why has it changed so much?

The first reports of the Kamchatka earthquake of the United States Geological Survey allowed it to 8.0 magnitude. Later, he was upgraded to an 8.8 magnitude earthquake.

“It is not uncommon for very, very large earthquakes in these first minutes,” said Tobin. “Our standard algorithms to determine the size of an earthquake saturated quickly. It is like setting up an amp and obtaining a lot of distortion.”

One of the first signs that the earthquake was stronger than initial seismic relationships was an initial measure of a buoy at around 275 miles southeast of the Kamchatka peninsula.

The buoy, which is part of the dart system of the National Oceanographic and Atmospheric Administration (assessment and report of the tsunamis), is connected to a pressure sensor of the seabed at around 4 miles below the surface.

The sensor recorded a 90 centimeter wave, which is in the process of eyes for tsunami researchers.

“This is the second recording we have never seen in the tsunami world,” said Vasily Titov, a Senior Tsunami modeler at the Noaa Environmental Laboratory Pacific, adding that this indicated that there was “a catastrophic tsunami spreading to the ocean”.

Titov said that the only higher reading came from the 2011 Tothoku Tsunami and Tsunami, which caused nearly 16,000 deaths in Japan.

The seismic models later confirmed that the earthquake on Wednesday was an 8.8 magnitude, which means that it released almost 16 times more energy than an earthquake of magnitude 8.0, according to a tool for calculating the USGS.

Tōhoku was much larger.

Tobin estimated that the earthquake released 2 to 3 times more energy than that observed in Kamchatka. Titov said tsunami in Japan was also about three times larger.

In addition, Tobin said that the Tōhoku earthquake “had produced an abnormally large movement of the seabed”, elongating and moving more water than expected, even for an earthquake of its magnitude.

In Kamchatka, “it is likely that there was less trip from the seabed than what could have happened in the worst case or a more disastrous scenario for a magnitude 8.8,” said Tobin, although more research is necessary to confirm this theory.

How did the researchers do a forecast? What was the quality of forecasts?

In two hours, the researchers produced tsunami forecasts for “almost the whole Pacific and for warning points along the American coasts,” said Titov, with predictions of water levels at the coastal tide and also for a flood.

The tsunami took about eight hours reaching Hawaii and 12 hours to reach the Californian coast.

Titov, who helped build the models used by forecastists who issue warnings from national tsunami alert centers in Hawaii and Alaska, said models are based on seismic data and the network of more than 70 dart buoys in place along the Pacific Jim, which feel pressure changes. The United States has and operating more than half of dart buoys.

Titov said the models indicated that the northern shore areas of Hawaii would receive tsunami waves of about two meters or less.

“Hilo was planned about two meters [6.5 feet] And it materialized about 150 centimeters ”, or 1.5 meters [5 feet]Said Titov. “This is exactly how we want – a bit on the conservative side.”

The same trend took place in parts of California, said Titov.

It will take a long time to assess to what extent the models predicted the flood, because the reports always take place in the extent of the floods.

“We know that the floods took place in Hawaii. We do not know exactly the measure, but according to the reports I have seen on television, it looks exactly like what we predicted,” said Titov.

Why were people in Hawaii evacuated for a wave of five feet?

Yong Wei, a tsunami modeler and principal researcher at the University of Washington and the Noaa Center for Tsunami Research, said a 1.5 meters [5 foot] The tsunami wave can be very dangerous, especially in shallow waters off Hawaii.

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

Wei said that the wave of the waist that struck Hawaii can break out inside “tens of meters”, produces dangerous currents and damage boats and other mobile objects.

“People die. If they stay there and get no warnings, two meters can certainly kill people,” said Wei. “If you are on the beach, strong currents can certainly get you out in the ocean and people drown.”

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

“I don’t want people to think, oh, we had a warning and did nothing and did not poop -” I can ignore it, “said Tobin. “Warnings by nature must be mistaken on the side of caution.”

Was it a historic event?

No. The Kamchatka peninsula has a long history of earthquakes.

“It was an area that was ready for another earthquake and that there had been many earthquakes in this region in recent weeks,” said Breanyn Macinnes, professor in the Department of Geological Sciences at the Central University of Washington, which indicates an increased risk.

In 1952, before scientists included a strong understanding of plates tectonics, a 9.0 gross earthquake struck off the Kamchatka peninsula in the same region, sending a tsunami to the city of Severo-Kurilsk.

“People in Russia were not really prepared for it. It was a very big earthquake, a big tsunami and they were caught off guard,” said Macinnes.

Macinnes said that the product tsunami was between 30 and 60 feet high in the southern parts of the peninsula.

“Thousands of people have been killed and, fundamentally, the city has been destroyed,” said Joanne Bourgeois, emeritus professor of sedimentology at the University of Washington, who has been studying the history of the region tremor for about three decades.

How would the tsunami alert system work if the earthquake was getting closer to home?

Kamchatka tsunami is a megathrust earthquake produced along the large flaw in the subduction area, when a tectonic plate is forced under another. The American West Coast presents a similar flaw, called the Subduction Zone of Cascadia, which takes place off the coast along the American West Coast in northern California on northern island of Vancouver.

“It’s a kind of mirror image across the Pacific,” said Tobin. “An 8.8 with a relatively shallow depth in Cascadia is definitively in the field of scenarios. We may have a similar event here. ”

In fact, Cascadia has the potential to produce much larger earthquakes, said Tobin. Modeling suggests that Cascadia could produce tsunami waves as high as 100 feet.

The earthquakes in the subduction zone generally produce tsunamis which reach shore in about 30 minutes to an hour, said Titov, which would reflect the capacities of forecastists to predict the effects of tsunami precisely along the American West Coast before the flood occurs.

Titov said more sensors on sea planks, more computer processing and innovation with artificial intelligence algorithms are needed to accelerate forecasts.

Tobin said that Tsunami’s successful warning on Tuesday should stimulate investments in seabed sensors and offshore seismic surveillance stations along the subduction area.

“This shows the value and importance of the NOAA and the USGS [U.S. Geological Survey] In these times when some of these government agencies have been questioned, “said Tobin.” We would not have had a warning from Tsunami if there was no Noaa and the next one could be a closer event. They showed their value.