Did you know that the force of the 2004 Indian Ocean tsunami wave has killed over 200,000 people? That in less than 24 hours a tsunami can travel over the Pacific Ocean? And that unlike other waves, tsunami waves don’t curl nor break? A tsunami is a series of huge waves happening after an undersea disturbance. These include volcanic eruptions, landslides, meteors, other movements on the earth’s surface and most importantly earthquakes. The waves travel in all directions radiating out from the disturbance, and collect mass and volume as they travel. Out at sea, these waves travel inconspicuously and usually unnoticed, since they are mostly underneath the water surface. Even a wave travelling very quickly, such as 700 kilometers per hour, is only one meter high out at sea. At one point, however, these waves reach the shore. Because of the continental shelf, instead of growing larger underneath the water surface the tsunami starts gaining height and smashes onto the shore. The waves can be as high as 100 feet. When these waves hit the shore, they cause tremendous destruction. The great energy from a tsunami can lift boulders, flip vehicles, and demolish houses. This is why they are so feared.
Effects of Tsunami
Where the ocean is deep, tsunamis can travel unnoticed on the surface at speeds up to 500 miles an hour (800 kilometers an hour), crossing an ocean in a day. These tsunamis then have terrible effects. In a tsunami affected region, people will be altered in many ways. We lose lives, friends and families. Property is lost or destroyed, and livestock is ruined. Jobs are lost, and money is scarce, leading to a negative impact on the region’s economy. Extreme changes will be made to community’s lifestyles. Tsunamis don’t only have negative effects on people, but also on the environment. Many wild and domesticated animals will be killed, or will have their natural habitats destroyed, which might lead to extinction. The sea will be cluttered with debris. Land next to the sea will be completely wiped out, and precious coral reefs and mangrove areas (if in tropical climate) will be crushed by the wave, that can take decades to grow back. As you can see, tsunamis aren’t something to mess around with and can deeply alter anyone’s lifestyle.
Earthquake/Seismograph Detection Systems
An earthquake is a natural tsunami warning, as most tsunamis throughout history have been caused by underwater earthquakes or other tectonic movement. The place where the first slip in the rock or jagged motion is made is called the focus, deep down in a fault underground. The epicenter is located above the focus, and is where the first seismic waves are formed. This can be a meter above the focus, or 50 kilometers. When the seismic waves start radiating from the epicenter, the earthquake is first created. The shaking of the ground radiates at a constant speed. Earthquakes are measured and recorded using an instrument called a seismograph. Seismographs all around the world record these movements, and they can tell if the earthquakes are big or small, using the seismograms produced. A seismograph is made up of a pen hanging on a string. This string is attached to something steady, and the pen should not be moving. When the ground moves, the pen draws the movements. The results are squiggly lines called seismograms, and from these we can measure the earthquakes, and make tell whether they are big or small and what kind of a tsunami they would produce. However, we cannot state that every earthquake ever made will cause a tsunami matching up with its size, since not many out of the millions of the earthquakes that have happened throughout history have caused tsunamis. There is no way to know if a submarine earthquake will cause a tsunami, not even Tsunami Warning Centers can tell. Therefore, although seismograms are very precise and helpful devices, they are only the first line of defense against tsunamis, but on their own they would lead us to false alarms.
Animal Sensory
Animal sensory is another way of predicting when exactly a tsunami is about to happen. It is believed that animals have a kind of “sixth sense”, which save them from vast tsunamis and earthquakes. Many animals possess the quality of being able to detect tsunamis in advance. Snakes were seen slithering out from their dens in the middle of winter hibernation. Elephants were breaking the chains tying them to trees and running up hills, carrying the tourists on their backs to safety. Dogs refused to go outside. Flamingos avoided their lower lying breeding areas. Zoo animals rejected leaving their shelters. Scientists have been trying to see if there is any possible way for humans to use this animal sense for better tsunami warning systems, but have so far been unsuccessful. Wildlife experts believe that animals can hear or feel the seismic waves in the earth. They can know a natural disaster is arriving long before humans might detect that something is there. Therefore, if we see that the animals are acting strange in areas with a potential chance of a tsunami, we can assume that something might be happening deep out at sea coming right toward us.
Buoy and Satellite Warning System
Deep- Ocean Assessment and Reporting of Tsunami (DART) are sensors using deep- sea pressure changes to sense tsunami waves. They were first invented by the Pacific Marine Environmental Laboratory (PMEL) in the United States. These are buoys placed far our at sea, preferably at least at 3000 meters depth. The buoys are composed of two parts: the sensors on the ocean floor, and the buoy on the water surface. The sensors have quartz crystal resonators to measure pressure and temperature far down in the ocean. It records the changes in water pressure and sends all of the information to the buoy thousands of meters overhead. The sensors are capable of recording changes as small as a millimeter in the water surface. They buoy passes the information on via satellite, which gives it to the hands of the tsunami warning center. If an unusually strong current or if there’s a lot of pressure detected with the sensors on the ocean floor, it gets switched from “standard” to “event” mode. “Standard” mode is the normal mode, where the sensors collect information and send it up to the buoys every 15 minutes or so. However, when a buoy is changed into “event” mode, information is gathered and sent up every one minute. This happens when there is potential for a tsunami overhead, and when the seismic waves are especially strong. When the tsunami warning center receives these pieces of information, they send out warnings to the places at risk. That is when the buoys have completed their task and the responsibility is on the local operation centers for getting the community ready for a possible tsunami.
Impacts on Warning Systems on Society
Many changes have been made to present day communities to withstand stronger tsunamis and to make us safer. Today children are being educated at an early age and being opened up to the potential danger of a tsunami. Whole communities are aware of exactly what they should do in case they hear a tsunami warning signal. Safer houses are being built to resist tsunamis and other natural disasters. Some things that tsunami safe houses have are metal connectors to strengthen the houses frame, bolts to hold the house to its concrete foundation, and plywood to strengthen walls. Many people have tsunami safe buildings, and the governments are encouraging them even more. Newer buildings have to be stronger and more flexible, and older ones have to be added to to survive stronger forces. Governments have also adapted after tsunamis have occurred. For example, after the 2004 tsunami of the Indian Ocean, the government decided to rebuild the destroyed cities and small towns further away from the coastline. It was forbidden to build any construction within 100 meters in the Southwest and 200 meters in the Northeast from the sea. Many improvements have been made over warning systems over the years, and much money has been spent by our governments to try to keep our communities as tsunami- safe as possible.
These are some safety tips that are essential to follow in the case of a tsunami:
1. Go to high ground, preferably least ten meters above sea level.
2. Use your local radio for information about the wave.
3. Do not use your mobile phone unless in the case of a life- threatening emergency.
4. Know your evacuation routes and paths.
5. Prepare yourself beforehand to stay on your own for three days, with a supply kit.
6. Tsunamis are likely to travel up streams or rivers that lead to the ocean. Avoid these as you would avoid the beach.
7. Don’t travel by car, for roads might be broken, and footpaths are usually the best paths to high ground.
8. If you are unable to go to high ground, go inlands. If you are unable to do that, go to the top floor of a building, preferably three stories or above. As a last resort, climb a sturdy tree.
Remember: A tsunami is a series of waves, and the first wave might not be the most dangerous one. Stay at high ground until you can hear the “all safe” signal.
As you can see, tsunamis are a serious issue and can lead to great damage; which is why we should be prepared and aware of them in all situations. We can use seismographs to detect earthquakes, the main cause of tsunamis, but although a large earthquake is arriving we cannot know that it is going to form a tsunami. Animals can let us know through their behavior if there are large seismic movements, so we should always be aware and notice our surroundings. Using buoys and satellite systems we can detect changes deep down in the ocean and send out warnings to places at risk, but even these won’t stop the tsunami entirely from happening. We always have to be prepared for a tsunami to strike, and follow all the warnings and steps to survive. Although we have excellent government protection, seismographs, animals’ “6th sense”, buoys and satellite systems, when we narrow it down it is us the responsibility is on, we are in charge of keeping ourselves safe.
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