Tsunamis seem like large waves of water destroying everything in their path. They seem like massive walls that will relentlessly claim their role in the list of dangerous natural disasters. Note the key word: seem.
Tsunamis are those points and worse. How do you get worse than a wall of water? A frozen wall of water? No, that would stay still. A boiling wall of water? Nah, too semi-gaseuous. The way that a wall of water about to crash onto you is dangerous is the way of the water.
Water seems to be one of the safest substances around. Sure, you can drown in it, but that's kind of evolution's fault, if we can't breathe underwater, there's probably a reason for it. Compare water with any other common substance. Dirt: can permanently blind you, can suffocate you, can get stuffed up your nostrils. Sand: can scratch your eyes, can also suffocate you, can also get in your eyes. Wow. Practically all solids can kill the same way. But sand leads to the creation of glass, and glass can also blind you, can sever limbs.
In contrast to all these natural causes of death, water seems harmless. But the true terror lies in the force of water. Water, when accumulated, gets an insanely high weight. A cubic yard of water has- drumroll please- a weight of 1,700 pounds. That's... a lot. I couldn't get a hold on how much psi that cubic yard of water would do to you, but lets leave it at enough to crush your skull if more than one hit you at forty miles an hour.
Basically, imagine getting hit by a speeding truck while you move towards it. In essense, tsunamis are dangerous, and knowledge of suggested precautions and how they form will greatly increase chances of survival in the event of a tsunami.
Tsunamis are those points and worse. How do you get worse than a wall of water? A frozen wall of water? No, that would stay still. A boiling wall of water? Nah, too semi-gaseuous. The way that a wall of water about to crash onto you is dangerous is the way of the water.
Water seems to be one of the safest substances around. Sure, you can drown in it, but that's kind of evolution's fault, if we can't breathe underwater, there's probably a reason for it. Compare water with any other common substance. Dirt: can permanently blind you, can suffocate you, can get stuffed up your nostrils. Sand: can scratch your eyes, can also suffocate you, can also get in your eyes. Wow. Practically all solids can kill the same way. But sand leads to the creation of glass, and glass can also blind you, can sever limbs.
In contrast to all these natural causes of death, water seems harmless. But the true terror lies in the force of water. Water, when accumulated, gets an insanely high weight. A cubic yard of water has- drumroll please- a weight of 1,700 pounds. That's... a lot. I couldn't get a hold on how much psi that cubic yard of water would do to you, but lets leave it at enough to crush your skull if more than one hit you at forty miles an hour.
Basically, imagine getting hit by a speeding truck while you move towards it. In essense, tsunamis are dangerous, and knowledge of suggested precautions and how they form will greatly increase chances of survival in the event of a tsunami.
According to tsunami.noaa.gov, referred to as NOAA, “A tsunami is a series of ocean waves generated by sudden displacements in the sea floor, landslides, or volcanic activity. In the deep ocean, the tsunami wave may only be a few inches high. The tsunami wave may come gently ashore or may increase in height to become a fast moving wall of turbulent water several meters high.” Tsunamis cannot be prevented, but its impact can be lessened by background knowledge and preparation.
Though a fat lot of good knowledge will do you when you face the Wide Wall of Water.
Though a fat lot of good knowledge will do you when you face the Wide Wall of Water.
These monstrous waves are relentless in their destruction. These waves have caused over 420,000 lives to be lost and billions of dollars of damage to the communities they ravage.
Major tsunamis are scarce. That fact may be a consolation to you and me, but to those who were hit by a tsunami aren't as glad.
Often, major tsunamis only occur once every few years, but cause tons of damage. For example, in 2004, a day after Christmas, a tsunami struck and killed about 130,000 people close to its origin earthquake and around 58,000 people on further shores.
Often, major tsunamis only occur once every few years, but cause tons of damage. For example, in 2004, a day after Christmas, a tsunami struck and killed about 130,000 people close to its origin earthquake and around 58,000 people on further shores.
Not only do these waves destroy the areas they hit, but they can be triggered by other large disturbances, meaning that a large earthquake in Taiwan could cause a tsunami in Europe. One prime example of this chain reaction is possibly the tsunami that struck Hawaii in 1946. An earthquake of the coast of the Aleutian Islands of Alaska created a series of waves that evolved into a tsunami. This wave grew to be as high as a 13 story building, in perspective, over 140 feet tall. The earthquake waves also split off and hit California and parts of South American. But the waves hit Hawaii hardest, and surges of water as high as two or three story buildings flooded its main island, killing 159 people and causing twenty-six million dollars in damage, back then. A leading theory for this tsunami is that the earthquake triggered a landslide, and the landslide and earthquake aftershocks both combined to set off the waves. Even after seventy years, the same tsunami’s cause continues to elude us.
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| Figure 1 Tsunamis cause devastation. An aerial view of Lampuuk in Sumatra after the town’s 7000 people were killed. Some 230,000 people in coastlines around the area were also affected. Picture credit John Stanmeyer, NG |
These tsunamis still can't be predicted, as undersea motion is unpredictable, but after a wave is detected, its path can be modeled.
Major Tsunamis are generally created by earthquakes of magnitude 7 or higher on the Richer Scale, and with a “shallow focus” (less than 30km deep in the earth) created by oceanic and continental plate movement. After a plate fracture, the plates give, and a vertical movement is created. This allows a “quick and efficient transfer of energy” from the floor to ocean.
Don't you feel better knowing the earthquake causing the next big tidal wave had an easy and efficient transfer of energy? Now, if only jobs were quick and efficient.
Don't you feel better knowing the earthquake causing the next big tidal wave had an easy and efficient transfer of energy? Now, if only jobs were quick and efficient.
One such powerful earthquake (9.3 magnitude) struck the coast of Indonesia in 2004, and the sea floor created a wave bank at least 30 meters (100 feet) in length. This claimed more than 240,000 people, and the shock waves reached Thailand, Sri Lanka, and India, and killed 58,000 more people.
These few examples have hopefully emphasized on the dangers and dangerous effects of tsunamis. Tsunamis are deadly, and as stated, there currently exists no accurate way to predict a tsunami, but a way to detect an oncoming tsunami does exist. Due to the sheer mass of continental plates, any major earthquake will cause a large effect, and this effect is so sudden, prediction is nigh impossible., but knowledge that one is forming is valuable.
There exists one such technology to detect oncoming tsunamis. The Rat Island Earthquake in Alaska, 17th of November 2003, set off an earthquake. This “generated a tsunami that was detected by three tsunameters located along the Aleutian Trench-the first tsunami detection by the newly developed real-time tsunameter system. These real-time data combined with the model database (2) were then used to produce the real-time model tsunami forecast. For the first time, tsunami model predictions were obtained during the tsunami propagation, before the waves had reached many coastlines. The initial offshore forecast was obtained immediately after preliminary earthquake parameters (location and magnitude Ms = 7.5) became available from the West Coast/Alaska TWC (about 15-20 minutes after the earthquake). The model estimates provided expected tsunami time series at tsunameter locations. When the closest tsunameter recorded the first tsunami wave, about 80 minutes after the tsunami, the model predictions were compared with the deep-ocean data and the updated forecast was adjusted immediately.”
This was detected using a relatively modern invention, deep ocean tsunami buoys. Each buoy is part of a system. The system involves a pressure sensor at the bottom of the sea, and the buoy itself. The pressure system detects seismic activity under the sea floor.
Each system can operate in two modes, standard and event. Standard mode is where the buoy satellites report every fifteen minutes to satellites, and are on a lower power mode to conserve battery. The mode measures sea levels. If the pressure sensor detects the movement of a wave spreading through the ocean, the buoy swaps into event mode. In event mode, the information is relayed every minute, sending sea levels to confirm a possible tsunami. If, in four hours, no further seismic activity is detected, the buoys turn back into standard mode.
These buoys are strategically positioned. The position has to be calculated carefully: they can't be too close to possible earthquake points, but they have to be close. They can't be too close as the proximity could ruin the data, because the earthquake and wave result could interfere with transmission. The buoys also have to be close enough to the earthquake epicenter to relay information fast enough to predict the oncoming tsunami. Buoys also have a depth condition, they generally must be placed in areas at least 3,000 meters deep, to prevent interference from surface waves.
These buoys do help in reality, as they are more reliable than relying solely on seismic data for tsunami prediction, and they reduce the amount of false alarms for tsunamis. Australia has started up a sea level stations around the sea, to increase the efficiency and accuracy of results.
These buoys are far from perfect though, they only have a life of around two to four years. They are, however, intricate: they can detect changes less than a millimeter in the ocean. Some of these buoys have a two way communication system, where they can communicate with a manual controller, to swap into event mode if necessary.
But its not like those buoys do anything. All that they do is tell you that there is probably a tsunami incoming. Doesn't it feel great to know you're safe?
Even with the detection, micro and major tsunamis happen all the time, and ultimately cannot be stopped, but the damages and casualties could be prevented with more awareness and responses. There currently exist a large amount of tsunami precautions: for both before and after the wave hits.
National Geographic suggests three things to stay safe from tsunamis: knowledge of local warning systems, a plan for evacuation, and knowing the warning sign of tsunamis. It also suggests to never stay at shore after a tsunami strike, and to not return until after authorities clear the area.
CWarn details safety a bit more. Firstly, they say that any strong earthquake more than 20 seconds can cause a tsunami. The organization goes on to suggest not to surf on tsunamis, as they are not surfable waves.
I repeat, I beg of you, I implore, don't be the one person who tries to ride a tsunami and get hit with the force of jackhammers to your skull. You may be an internet sensation because of stupidity, but you probably won't live to bask in the glory.
For safety tips, they suggest to know if the local area is prone to tsunamis, and if going to any area with risk of a tsunami, to know about any evacuation plans. They say to create and practice an evacuation plan, with specific measurements that are preferred: they say to try to aim for a hundred feet above sea level, preparation to get there by foot, and a place reachable in under fifteen minutes. Also important is to use a radio to know of local watches and warnings, and to talk it out with your insurance company to see whether they cover floods, and to discuss the risk with family to ensure everyone knows about tsunamis.
Protecting property is hard in the case of a tsunami. CWarn suggests not building a house near the coast, and to elevate homes, as most waves don't reach a height of more than ten feet. They advise an engineer to check the house for ways to make it more resistant, and to make a list of items for two purposes: to take in in case of a tsunami and to know what could possibly be missing. Above all, flood preparedness precautions should be followed.
That's a lot to keep in mind. Basically, run to high ground if there is a wave headed towards you, which most people have the common sense to do, then DON'T build a house near the shore, DO practice an evacuation pattern.
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| Figure 2 |
If a major earthquake strikes, it is advised to first drop, cover and hold on, especially if the earthquake lasts more than twenty seconds. Next, evacuate the area with your family, and avoid downed power lines.
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| Figure 3: Most tsunamis are centered around the Pacific Ring of Fire. Picture credit V Gusiakov Russian Academy of Science |
The major question that most people have is: what is the pattern in tsunamis? In recap, these are giant waves, caused by large disturbances, normally earthquakes of magnitude 7 or more, reaching heights up to 140 feet. Analyzing maps of major tsunamis (figure 2), some patterns show. a) major tsunamis occur around ten to twelve times a century b) most tsunamis occur within a ring of fire (figure 3). There are certain locations that are more prone to tsunamis than others. According to scientist analysis, 76% of major tsunamis occur in the Pacific Ocean and its seas, a whopping 10% in the Mediterranean Sea, 11% more in the Atlantic Ocean, and 3% in the Indian Ocean. This, however, doesn't accurately reflect damage: in less “geologically active” oceans such as the Atlantic and Indian Oceans, the damages cause significant damage.
Most tsunamis do occur in the Pacific, however, and that may be the one constant about tsunamis.
These monster waves are disastrous in their effects, in damage and casualties. They are truly unpredictable, and have proven in the last four score years (eighty years for all you non-english nerdy people) how deadly they are.
References for this document include
tsunami.noaa.gov: a great site to find more information about tsunami and impacts.
http://www.livescience.com/3732-mystery-deadly-1946-tsunami-deepens.html: a post detailing the tsunami of 1946 and its possible causes.
http://tsunami.noaa.gov/tsunami_story.html One of the pages on tsunamis, detailing the detection and formation
http://www.nationalgeographic.com/environment/natural-disasters/tsunami-safety-tips/ Tsunami safety described.
http://cwarn.org/tsunami/be-prepared A more in depth description of safety.
http://www.bom.gov.au/tsunami/about/detection_buoys.shtml Information on buoys, Australian ocean web, so is about Australia, but most buoys are standard, as the DART (Deep-ocean Assessment and Reporting of Tsunamis) II (current version) was originally developed in the US by the Pacific Marine Enviromental Laboratory (PMEL) of NOAA. NOAA is a reference as well
http://www.sms-tsunami-warning.com/pages/tsunami-history#.WLduMbw8KhA A great webpage that analyzes the patterns and locations
Picture credits: figure 1: John Stanmeyer, NG Staff, figure 2: V Gusiakov Russian Academy of Science, figure 3: www.sms-tsunami-warning.com
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