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In March 2011, Japan was struck by a magnitude 9.0 earthquake and a following tsunami. Authorities concluded that the earthquake was the cause of the Pacific plate releasing the friction built up after years converged under the North American plate (as shown in figure 3) along the fault line that lies kilometres away from Japan’s coastline. (Urbano, 2011)This caused the friction to spread through the ground-and what was originally said to be a magnitude 6.6 earthquake through the evaluation of incomprehensive readings from seismometers- shook Japan for over five minutes. The resulting tsunami was triggered by the explosive energy released by the earthquake. However, its damage was minimized by 10m high sea walls and the modeling of buildings along the coast, which had applied various scientific techniques to reduce impact from waves on actual buildings. Macintosh HD:Users:160161:Desktop:Unknown-1.jpeg
Earthquakes are a very significant problem around the globe and can cause havoc through towns. The Japan earthquake and following tsunami resulted in 20000 deaths and caused the destruction of entire towns and many coastal areas of the country- the most notably being the TÅhoku region in Honshu. (Pletcher, 2013) A large percentage of the damage and lives lost could have been avoided if sciences techniques in detecting earthquakes- such as seismometers- would have alerted authorities in advance rather than minutes before the earthquake struck, as well as conveyed more accurate readings.
Around the globe scientists and organisations have attempted to develop method of detecting earthquakes so that maximum damage can be prevented. Currently, around the globe seismometers, sea walls and building modeling are used to detect earthquakes through the readings of seismic waves. This scientific solution has potential to minimise damage from earthquakes and tsunamis around the globe if implemented correctly and its negatives minimized.
The Application of Science To Detect Earthquakes and Consequently Prevent Damage-Seismometers
Earthquakes can be detected by measuring the frequency of the seismic waves in a particular area using a scientific device such as a seismometer. Seismic waves are circular waves (see figure 4) created by the back and forth movement that occurs when an earthquake shakes the ground, thus releasing waves. A magnitude 8 or 9 earthquake- like the one in Japan 2011, are caused due to the faster and rapider movement of the ground. This releases a higher frequency of seismic waves that can be detected by scientific instruments like a seismometer-just as they were during the Fukushima earthquake.
The science behind the implementation of seismometers in earthquake prone areas such as Japan is that they use the basic principal of inertia to detect seismic waves in the earth’s surface. They consist of a ground motion detection sensor and a recording system. In a simple seismometer’s detection system, a weight and a spring are suspended from a frame that moves along with the earth’s surface. As the earth moves, the relative motion between the weight and the earth, which is caused by seismic waves is measured by the recording system which consists of a rotating drum attached to the frame, (as shown in diagram 1) and a pen attached to the mass.
This pencil moves along with the weight and the spring, leaving lines along the drum, which can be interpreted into determining the frequency of seismic waves and the magnitude of the coming earthquake by authorities.(Braile, 2000)Modern seismometers are electronic, and instead of using a pen and drum, the seismic activity generates an electrical voltage that is recorded by a computer. The reason why Japanese authorities and other nations around the world choose this science to help detect earthquakes is because it allows them to determine before hand when an earthquake is going to happen. Seismographs gather information over a long period of time and the patterns in the seismic wave frequency are easily analyzable.
Seismometers were implemented in Japan’s coastline by local authorities with readings going to computers where the data from seismic waves was analyzed. This brought to the early conclusions that the earthquake was a magnitude 6.6 and later upgraded to 9.0 from further readings showing an increase in movement within the ground. Seismometers also bring a change in scientific research about certain regions and their risk to earthquakes, as it allows for research to be collected at various points before, during and after an earthquake, so that warnings can be sent out in advance next time or before an aftershock. (Dea, 2003)
The Effectiveness of Detection/Damage Prevention Techniques Used In Japan
Seismometers- Science’s solution to the problem-can be used to detect earthquakes and their location so that maximum damage can be prevented. In theory, scientists in Japan should have been able to pick up the earthquakes where about, magnitude and timing from the seismic activity under the earth’s surface that should have been detected by numerous seismometers located on the Pacific Ocean’s seabed. Scientists can use the readings gathered- based on the frequency of the waves-to calculate the magnitude of the earthquake before it reaches by working out the difference in arrival between two waves from tree different seismometers. (BBC, 2013) If the gap between the two arrivals is shorter, then the magnitude of the earthquake is also higher. Fukushima scientists also used this method to determine the exact location of the earthquakes epicentre through the process of triangulation in which they determine the distance travelled by waves at each of the three seismometers and pinpoint the centre (as shown in diagram 2).
Seismometers certainly helped to detect the Fukushima earthquake. Evidence shows that almost a thousand lives were saved due to seismometers monitoring the Pacific seabed. They proved effective in saving lives because they were able to pick up the sudden seismic activity in the ground. The detection allowed scientists back in Japan to sound an alarm minutes before the earthquake arrived in Japan. However, the initial alarm was quite inaccurate, as it was originally sounded for a 6.6 magnitude earthquake. Over the last century around the world, scientists concluded that 9/10 times seismometers were initially incorrect in detecting the magnitude of the numerous earthquakes (Strevens, 2011).
Seismometers also have many more limitations, which cause for the technology to be deemed ineffective at times and can be used to partially explain some of the issues that occurred in Japan- issues that could have been avoided. Unlike NASA’s InSAR satellite technology that can detect earthquakes day before they occur (due to its ability to detect even 1cm of movement within the earth) (NASA, 2011), seismometers are only able to detect earthquakes minutes before they happen and the only way scientists can actually issue a warning in advance is if they look closely at the patterns in previous earthquakes or try and interpret seismic readings days before and see if there are any abnormalities. The limitations of possible inaccuracy with data and late warnings made the use of the seismometers quite ineffective during the earthquake. Although seismometers are able to pinpoint the exact location of the epicentre so that aftershocks can be predicted and are able to give a few minutes of warning about the magnitude, it is a scientific device that’s success can easily be affected by influence human error plays in analyzing its data on computers.
Sea walls were implemented in Japan to protect its coastal cities from tsunamis. The science behind them is that its strong concrete material, from which it is made of, should be able to block the force of a tsunami. Their height- 10 metres above sea level- were supposed to be sufficient to stop most tsunamis as evidence shows that it is very rare in any part of the world for a tsunami over 10m to a region that is not directly over the fault line. However, if a tsunami were to reach such heights, the sea walls success would be limited greatly. A positive of their use though, is that their success is largely predictable as they do not require any electronic systems to function and nor do they have any human influence. Macintosh HD:Users:160161:Desktop:Screen Shot 2013-10-27 at 6.40.21 PM.png
Sea walls proved ineffective in Japan as the tsunami proved to also be 10 metres tall due to the water being very deep in the region. This allowed the tsunami to build up its waves and when the tsunami’s biggest waves arrived at the coast of Japan, they were 1m taller than the walls event though they were still only 10m tall. (Tran, 2013) This was due to the fact that the coastline had dropped by a metre and also moved three metres out to sea. (As shown in figure 5) This outside influence limited the success of the walls greatly and although- in many other tsunamis sea wall have effectively haltered tsunamis due to their concrete strength and height- the tsunami of 2011 flooded into Japan killing thousands that could not escape in the few moments of warning.
Sciences Interaction With The Environment
The environment has minimal impact on the application and effectiveness of seismometers and sea walls. As seismometers are not affected by an areas air pollution, vegetation or climate, the environment does not play a significant role in positively or negatively affecting the detection ability of seismometers. However there are still a few minor factors- particularly in Japan- that can somewhat prevent an earthquake from being detected accurately. Due to Japans vulnerable earthquake-prone region being located along the Pacific Ocean’s coastline, many low intensity stress waves created by natural noises and ocean waves have the ability to be detected by seismometers. This is because seismometers can detect and measure motions with frequencies from 500 Hz to 0.00118 Hz- a large enough range to detect ocean waves- particularly in the Pacific Ocean. This could have a negative effect on the effectiveness of science’s solution. Negatively, seismometers could be alerting Japanese authorities every time tidal waves and ocean currents strengthen, thus triggering alarm bells constantly.
A positive effect that the Japanese environment has on damage preventing solutions such as sea walls is that the Japanese coastline has numerous mountain and hill landforms. The many hills and low mountains located in Japans coastal region (sea figure 6)-especially where the Fukushima earthquake struck-help to prevent damage due to there significant height above sea levels. This environmental benefit was evident during the 2011 earthquake as authorities guided civilians to high ground so that when the tsunami arrived and the sea walls failed, the landforms saved a few hundred lives. (ONISHI, 2011)This was because the 10m height of the tsunami eventually deteriorated by the time it reached the landforms, thus preventing further damage from occurring.
As mentioned above, the environment has minimal influence on the application and effectiveness of seismometers and sea walls, although sea walls do have an effect on the environment. To construct and implement sea walls, natural, agricultural and grassland is destroyed to make way for them. Sea walls require a large amount of space (width and length) if they are to be firm, sturdy and cover a large proportion of the coastline. They also negatively impact the climatic environment as their height to some extent interrupts the sea breeze that Japan receives from the ocean. This means that locations near the walls will be drier in the already tropical climate and environment. Once again these negative effects on Japan’s environment are not significant factors although if these scientific damage prevention measures were not present in Japan 2011, the environment would have been damaged greatly like it was in some towns that were destroyed completely.
Sciences detection and damage prevention solutions have a profound effect on the economy of Japan. The Japanese government invests billions (USD) in coastal defenses such as sea walls and warning systems every year. These expensive devices further cost governments around the world millions whenever a warning and consequent evacuation occurs. For example, since Hawaii’s Pacific Tsunami Warning Center was established in 1948, about 75 percent of warnings that resulted in costly evacuations turned out to be false alarms (Pendick, 2012).
A positive effect that Japan’s economy has on seismometers and warning systems is that it can afford to research deep into ways on improving the technology, as well as, fund the expensive costs involved with implementing and running them. There is very little limitations that Japan’s economy poses to seismometers as the economy is very stable and has been for the last decade without fluctuating too much (see graph 1), thus allowing for billions to be invested. This allows the government to invest in earthquake damage prevention devices so that when an earthquake strikes, damage costs can be kept to a minimum. Seismometers and damage prevention devices have a major influence on the economy. When the earthquake of 2011 struck and damage was high- especially from the burst reactor in the Fukushima Nuclear Plant- Japan’s tourism industry suffered greatly. This had a chain reaction on the economy with a major dip in Japan’s GDP (as shown in graph 1) during the period.
For many years now, scientists have attempted to come up with ways to detect and consequently, prevent earthquakes with measured success- especially in the Fukushima earthquake of 2011. Although the application of science through the use of seismometers potentially saved thousands of lives in the few minutes of warning, it’s accuracy and timing was not enough to stop a nuclear disaster. The 10m sea walls that were located around Japans shoreline also proved ineffective as the tsunami soared over them, leaving all types of buildings to be struck down by the shear force of the waves. However, scientists continue to apply their knowledge of earthquakes, tectonic movement and seismic waves so that they can enhance this solution for future earthquakes around the globe.
Seismometers and sea walls fit into the world environment nicely as they do not affect it, but rather help to prevent damage occurring to it, whilst the modeling of buildings simply has the same impact as normal buildings do. Economic wise though, billions of dollars are put into the science and evidence shown from Japan might suggest, too much money for fairly inconclusive success. There are some variables in science that we can’t control, but what can be controlled is minimizing their damage to civilization through the processes of detecting and preventing damage.
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