GPS, AIS and more: Diversifying the tsunami prediction technology

The Global Positioning System, which uses satellite transmission to locate the surface of the Earth, is a popular tool for those finding their way in new places. This article introduces innovative techniques used to more precisely define the earlier tsunami.

Reducing the human impact of disasters

Nine years have passed since the Great East Japan Earthquake on March 11, 2011. Despite all the scientific and technological advances of Japan, nearly 20,000 people lost their lives that day, mostly due to the resulting tsunami. As a scientist, I can only feel very sorry for this failure.

Japan is no stranger to disaster. In addition to earthquakes, they have long been hit by powerful hurricanes, which have killed thousands of people in the past. The Hurricane Isuan (Hurricane Vera) of 1959, for example, was the strongest typhoon since World War II, killing more than 5,000 people.

However, that disaster sparked a revolution in hurricane forecasting. The deployment of the Mount Fuji radar system, as well as new weather satellites, allowed advance warning and better evacuation, which resulted in a significant decrease in the number of hurricane deaths. Recently, about 100 people died when Typhoon Hagibus hit 2019 in eastern Japan, but without prior warning of radar and weather satellites, it is likely that many times this number has been lost.

Lessons from the 1960 Chile earthquake

Since the number of typhoons hitting Japan every year and the level of floods it brings has not changed significantly since the 1950s, this shows that improvements in prediction technology have saved lives. Likewise, any improvements in the accuracy of the tsunami prediction can reduce its human impact.

An earthquake with a magnitude of 9.5, the most powerful ever, struck Chile in 1960. He crossed the tsunami caused by the Pacific and arrived in Japan in about a day. Hawaiian observers have already sent information about the tsunami to the Japan Meteorological Agency, which deals with tsunami warnings locally, immediately after an earthquake. However, the JMA issued a warning only once the wave actually reached coastal areas in Japan. A distance from the epicenter of the earthquake should have given Japan nearly 24 hours to evacuate coastal areas, but 142 people are still losing their lives. This led to the need for a better alarm system.

Since then, Japan has strengthened international cooperation in this area, for example by increasing coordination with the Pacific Tsunami Warning Center in Hawaii and sharing more tsunami data. When the epicenter is in the seas near Japan, though – as was the case in 2011 – the problem remains how to warn people and minimize losses within a relatively short period of time before the wave actually hits.

Difficulty predicting a tsunami

Why is the tsunami so difficult to predict? The short answer is because it is difficult to determine how to get started. If we know where and how a tsunami begins, we can use computer simulations to quickly and accurately calculate its progress.

I imagine everyone has had homework problems like this one in high school:

Q: If a ball is dropped from a certain height, how long will it take to hit the ground, and how fast will it hit when it strikes?

Even those who are not familiar with physics will know that you cannot answer this question without knowing the initial height of the sphere. If you know the height, then the answer calculation is a simple matter in Newtonian physics.

In order to draw a resemblance to the problem of tsunami prediction, the problem of a tsunami’s starting state is the same as the sphere’s height. If we can know how a tsunami began – in other words, where and how far the sea level rose in the epicenter immediately after the earthquake – we can use accurate simulation to predict its magnitude and movement.

Tsunami Prediction Database

However, it is not easy to pinpoint that beginning. Using satellites to keep vast areas of the sea under constant visual surveillance for the discovery of a tsunami that can appear anywhere and anytime is a major challenge in terms of technology and cost.

There are also limitations to current prediction approaches. The traditional method for predicting a tsunami is based on the inverse calculation of the earthquake’s center and magnitude. There are two types of seismic waves: P waves (pressure waves), which travel at 7 kilometers per second, and S waves (shear waves), which travel at 4 kilometers per second. Measuring and separating these waves from multiple observation points allows the earthquake’s epicenter, size and magnitude to be calculated within minutes.

JMA estimated potential tsunami based on tens of thousands of potential sites and size combinations. By comparing the epicenter and actual magnitude with the information in the file, you can provide a prediction of how a tsunami will spread from the event.

However, this method is limited by relying on the calculations of the earthquake center and magnitude of the P and S waves, and it is only an accurate method for earthquakes to magnitude 8. Since the magnitude of earthquakes as large as the March 11 disaster cannot be calculated quickly and accurately using this method, the initial tsunami estimate JMA erred in reading the risk, basing its rating on 8-force vibration.

Thus, despite the wide range of data available to the JMA, she ended up reducing the significance of the tsunami by a large amount in size. A 9-magnitude earthquake releases about 30 times the power of 8, making failure accurate prediction of tsunamis impossible. With the Great East Japan earthquake, the failure to achieve accurate real-time measurement was linked to an insufficient tsunami warning. Based on the information they obtained, coastal residents ruled that the upcoming tsunami would not overtake the existing marine walls. This slowed the eviction orders, and ultimately, the death toll.

Tsunami prediction after 3/11

Since the Great East Japan Earthquake, the National Research and Development Agency of the National Research and Development Agency of the National Research and Development Agency has established the Japanese S-net Seismic and Tsunami Monitoring Network, stretching from seas off B البحارsō in Chiba to Tokachi in Hokkaido, in an attempt to help prevent deaths Future tsunami. The network is already running. Its measurement facilities combine seismic and tsunami sensors, and are connected to a total of 5,500 km of undersea optical fiber cables to exchange data in real time 24 hours a day. In preparation for the expected Nankai Trough earthquake, the agency also started deploying the Nankai Trough Network for Sea-Seism and Tsunami (N-Net) Monitoring off the Shikoku Coast.

N-Net uses equipment installed in areas likely to become the epicenter of future earthquakes, and because it directly reaches the sea floor, it is a particularly powerful tool. However, since the cables need to be placed on the sea floor and connected directly to the equipment, installation costs are high, as are maintenance operations.

These cost problems inspired a researcher to think of a way to quickly calculate a tsunami, for free. Associate Professor Inazu Daisuke at Tokyo University of Marine Science and Technology showed that data from the Automatic Identification System (AIS) that all installed vessels should have allowed a reverse calculation of the initial tsunami status based on changes in ship speed caused by the Great East Japan earthquake tsunami.

AIS transmits information in real time from most ships within a few tens of kilometers from shore, and in satellites in the near future it will allow the transfer of this data from ships located offshore. In other words, it would allow every ship in the sea to become a tsunami measuring instrument. It may be somewhat inaccurate as the number and distribution of ships is not fixed, but the fact that it only uses the existing infrastructure is a real benefit.

Discover the tsunami from space

There is also research into finding a tsunami from space, not on the surface of the oceans, in which I personally participate.

A sea-level tsunami bulge also pushes the air up, creating slow sound waves in the subsonic range. These sound waves reach an altitude of 300 km in about eight minutes.

At this height, solar radiation ionizes part of the thin atmosphere to create a state of matter called plasma. The generated ultrasound waves at the origin of the tsunami also oscillate with the plasma, and if we can measure this oscillation, they will allow indirect monitoring of the start state of the tsunami.

This becomes possible with GPS, a technology that is part of the daily life of many with the advent of navigation systems in cars and smartphones. GPS satellites orbit at an altitude of 20,200 km, many of which are close to Japanese airspace at any time. Japan’s Geospatial Information Authority has also established more than 1,300 reference stations operating continuously for geodetic purposes, and these points receive continuous transmissions from GPS satellites, and collect these data in one central location in real time.

The GPS transmitters sent to each base station carry the information that is captured while passing through the plasma layer. This can be used to measure plasma changes, allowing for accurate determination of the onset of a tsunami. Currently, it takes about 20 minutes to record a tsunami caused by an earthquake in a 9 degree range, and technology is being developed to bring this down to about 12 minutes.

The biggest benefit of this technology is its use of the existing GPS infrastructure. We can create a system to monitor every tsunami in the seas near Japan from space without any initial installation costs. Moreover, this technology can also be expanded to include countries that lack the financial resources to implement such technology infrastructure on their own. If we can achieve accurate tsunami forecasts at low cost, this will be a really appropriate way for Japan to help pay off the massive influx of global support it has received after the tragic tsunami.

Science and technology and the desire to save lives

Just as our predecessors introduced storm-prediction techniques after the heavy losses in Hurricane Isiyuan, we researchers today have a duty to advance research and development to prevent a recurrence of the massive losses of the Great East Japan earthquake, if another massive tsunami hits Japan.

Since March 2011, many tsunami prediction projects have been launched other than those mentioned above. All of them are still under development, but it seems clear that due to the difficulty of accurate earthquake and tsunami prediction, a varied approach that mixes different forecasting systems, taking advantage of the strengths of each, will be more effective. Matching complementary systems can allow one to cover the shortcomings of another, and thus help save more lives.

At the same time, we must realize that there is still no “magic” prediction technique. Individuals still need to use their experience, intuition, and daily preparation to help mitigate the tsunami. People living in coastal areas should check the location of the closest high safety areas and evacuation centers. If they feel a major tremor, they should be aware of the possibility of a tsunami and evacuation.

Japan is in the hot spot of an earthquake, so there is no way to completely avoid tsunami damage. But many scientists are directing their efforts to reduce loss of life, albeit slightly.

(Originally published in Japanese. Image title: View near the fishing port of Matsukawara in Soma, Fukushima Prefecture, after the tsunami damage on March 11, 2011. With permission from the Fire Science Center.)

.

What Are The Main Benefits Of Comparing Car Insurance Quotes Online

LOS ANGELES, CA / ACCESSWIRE / June 24, 2020, / Compare-autoinsurance.Org has launched a new blog post that presents the main benefits of comparing multiple car insurance quotes. For more info and free online quotes, please visit https://compare-autoinsurance.Org/the-advantages-of-comparing-prices-with-car-insurance-quotes-online/ The modern society has numerous technological advantages. One important advantage is the speed at which information is sent and received. With the help of the internet, the shopping habits of many persons have drastically changed. The car insurance industry hasn't remained untouched by these changes. On the internet, drivers can compare insurance prices and find out which sellers have the best offers. View photos The advantages of comparing online car insurance quotes are the following: Online quotes can be obtained from anywhere and at any time. Unlike physical insurance agencies, websites don't have a specific schedule and they are available at any time. Drivers that have busy working schedules, can compare quotes from anywhere and at any time, even at midnight. Multiple choices. Almost all insurance providers, no matter if they are well-known brands or just local insurers, have an online presence. Online quotes will allow policyholders the chance to discover multiple insurance companies and check their prices. Drivers are no longer required to get quotes from just a few known insurance companies. Also, local and regional insurers can provide lower insurance rates for the same services. Accurate insurance estimates. Online quotes can only be accurate if the customers provide accurate and real info about their car models and driving history. Lying about past driving incidents can make the price estimates to be lower, but when dealing with an insurance company lying to them is useless. Usually, insurance companies will do research about a potential customer before granting him coverage. Online quotes can be sorted easily. Although drivers are recommended to not choose a policy just based on its price, drivers can easily sort quotes by insurance price. Using brokerage websites will allow drivers to get quotes from multiple insurers, thus making the comparison faster and easier. For additional info, money-saving tips, and free car insurance quotes, visit https://compare-autoinsurance.Org/ Compare-autoinsurance.Org is an online provider of life, home, health, and auto insurance quotes. This website is unique because it does not simply stick to one kind of insurance provider, but brings the clients the best deals from many different online insurance carriers. In this way, clients have access to offers from multiple carriers all in one place: this website. On this site, customers have access to quotes for insurance plans from various agencies, such as local or nationwide agencies, brand names insurance companies, etc. "Online quotes can easily help drivers obtain better car insurance deals. All they have to do is to complete an online form with accurate and real info, then compare prices", said Russell Rabichev, Marketing Director of Internet Marketing Company. CONTACT: Company Name: Internet Marketing CompanyPerson for contact Name: Gurgu CPhone Number: (818) 359-3898Email: [email protected]: https://compare-autoinsurance.Org/ SOURCE: Compare-autoinsurance.Org View source version on accesswire.Com:https://www.Accesswire.Com/595055/What-Are-The-Main-Benefits-Of-Comparing-Car-Insurance-Quotes-Online View photos