Earthquake essay - Grade: A PDF

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Earthquake essay: analysis of causes of earthquakes and preparation for these natural disasters...

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November 5, 2017 Unit 3: Assignment There are many different factors that can cause earthquakes, but most of them can be explained by the plate tectonic theory, which says that the movement of the earth along faults generate earthquakes. Earthquake prediction is a relatively new science, beginning in earnest in the 1970s. Earthquakes can be predicted in the long term using the paleoseismology approach for some faults, but not for all. According to Abbott’s text, the timing of fault movement can be split into three groups: quasi-periodic movement, clustered movement, and random movement (Abbott 115). Using the techniques of paleoseismology, faults that have semi-regular patterns of movement can be more easily predicted in the long term. However, faults that fall into the third category, such as the San Andreas fault, have no pattern of their movements and are much more difficult to predict. This method of earthquake prediction based on an area’s history has been successful in some cases. In December 1988, scientists predicted the World Series earthquake that would occur ten months later (Abbott 116). Unfortunately, short-term prediction for earthquakes is much less reliable. In 1988, the International Association of Seismology and Physics of the Earth’s Interior (IASPEI) created a list of five significant earthquake precursors that might aid in prediction. Three were seismicity patterns, one involved ground-water chemistry and temperature, and one is a measure of crustal deformation (Wyss). However, it was decided that these precursors were not understood well enough to be useful in predicting earthquakes in the short term. As of now, Abbott writes that we are not close to having the capability to make short-term earthquake predictions (116). The future of earthquake preparedness lies not in being able to predict them, but in being able to live with them and mitigate damages. Abbott describes early warning systems that are being developed and having increasing success. The system does not predict when an earthquake will happen, but warns that

it has already begun, giving people time to prepare. It works by detecting differences in velocity of seismic waves and alerting people to the intensity and time of the upcoming earthquake (Abbott 117). Currently, Japan is the only country with a nationwide early warning system, but it will likely spread in the future and the technology can be used to aid in preparedness for these disasters. Two countries that have frequently been impacted by these disasters are Japan and China. One such earthquake in Japan was the Great Kanto Earthquake of 1923. The cities of Tokyo and Yokohama were both impacted by a series of earthquakes on September 1, 1923. During this event, the three main causes of destruction were tsunamis caused by seismic sea waves, fires started by combustible construction materials that their structures were built out of, and destruction from the earthquakes themselves. Houses were demolished, tunnels and bridges collapsed, and overall 71% of Tokyo and 100% of Yokohama were were destroyed (Abbott 85). They learned from the disaster in 1923 and prepared for future earthquakes by building cities with wider streets and more open spaces for people to get away, and using less combustible building materials to prevent future fires. The economic cost of the disaster was 6.5 billion yen, four times larger than Japan’s national budget (Schencking 296). However, many people say it as an opportunity to rebuild their capital. In the process of recovery, the mindset of the nation was changed. Many people believed that Japan in the wake of the earthquake was “a watershed between prosperity and decline of a nation” (Schencking 296). The final budget for reconstruction was 744 million yen. Through the process of land readjustment, Tokyo claimed residential land for public use and used it to build roads, sidewalks, parks, and other facilities (“Reconstruction”). Reconstruction was a six year process that resulted in a completely new city (figure 1). According to the Central Intelligence Agency, the population of Japan is currently 127 million. At the time of the Great Kanto Earthquake in 1923, the population was approximately 58 million (“Japan”). Based on projected population data, the population is expected to decline to 107 million by 2050 (“Population Pyramid”). Earthquakes and tsunamis are the most frequent natural disasters to

occur in Japan. There are also several active volcanoes in Japan. Due to large amounts of rainfall and steep incline of the land, Japan experiences many wind and water related disasters. Finally, Japanese typhoon season runs from June to December, which can lead to high tides, landslides, and flooding (“Japan - Natural Disasters”). The Japanese have responded to the threat of tsunamis and typhoons building walls along the coastline, large gates and the entrances to harbors, and early warning systems. However, they still feel the effects of the disasters, including the 2011 tsunami, the world’s most expensive natural disaster (Abbott 201). The second earthquake to be discussed in this paper is more recent. It occurred in Sichaun, China, in 2008. The earthquake occurred along the Longmenshan fault for 250 km, and lasted around two minutes. The textbook describes it as a mountain building thrust-fault event that was caused by India colliding with Asia. According to the textbook, similar events over time are what built the Dragon’s Gate Mountains in the area. While plate tectonics caused the earthquake, there were also other factors that triggered the disaster. This earthquake is under the human-triggered category of the Abbott textbook. One man-made factor that lead to this disaster was the construction of a dam in 2005. The reservoir held 900 million tons of water, and the weight of the water and the pressure of it seeping underground caused the land to warp, which may have triggered the movement of the fault (Abbott 119). This disaster resulted in the deaths of about 87,500 people, and left 5 million people homeless. Buildings were made of concrete with little support steel, so buildings collapsed easily during the earthquake. The textbook also says time of day was a factor in the death toll. The earthquake took place at 2.28 PM, meaning schools and office buildings were full of people when they collapsed. The Chineses government responded to the disaster with recovery efforts immediately, seeing it as an opportunity for reconstruction similarly to the Japanese. According to the World Bank, 41,130 reconstruction projects were undertaken, 99% of which were completed within two years (Bernal). Public-service facilities were also retrofitted and given more modern equipment, a project which cost

approximately $16.6 billion (Bernal). Although the area recovered physically and economically from the earthquake, the people did not fully recover. There are many investigations and suggestions of corruption that indicate the disaster was caused or made worse by officials. According to former Prime Minister Wen Jiabao, “‘Selectively publishing’ victims’ names showed authorities feared admitting that inadequate construction and poor governance had claimed so many young lives” (Phillips). The lack of acknowledgement of the children lost in this disaster means that many of the victims’ families cannot recover. The population of China at the time of the disaster in 2008 was 1.325 billion. Since then, the population has increased slightly to 1.379 billion (“Population, Total”). According to the population pyramid, similarly to Japan, the population of China is expected to decline by 2050 to 1.348 billion. Being in an active seismic zone, earthquakes are the most common natural disaster one might experience in China. China is the location of history’s deadliest earthquake, occurring in 1556 and causing the deaths of 830,000 people (Abbott 91). However, flooding and typhoons also pose a threat (“China - Natural Disasters”). The Huang or Yellow River is also known as “The River of Sorrow” because it reputedly has killed more people than any other natural feature in China due to flooding (Abbott 366). China and Japan actually responded to the earthquakes fairly similarly. Both disasters resulted in major destruction. In response, the government of China and Japan used the disaster as an opportunity to rebuild the area better and more modern. They also rebuilt so that inhabitants would be more prepared for future earthquakes. The hope after reconstruction was that they would be able to prevent damage like this from happening again. I think they responded so similarly simply because of the magnitude of the disaster. Were the earthquakes smaller and had they done less damage, they might have been more able to vary their responses. However, when faced with this level of destruction and loss of life, the only choice is to take preventative action and try to make sure the disaster cannot repeat itself.

Figure 1: The reconstruction plan of Tokyo in the wake of the Great Kanto Earthquake of 1923 (“Reconstruction”).

Works Cited Abbott, Patrick L. Natural disasters. 10th ed., McGraw-Hill, 2017. Bernal, Vivian Argueta. “Four Years On: What China got Right When Rebuilding After the Sichuan Earthquake.” East Asia & Pacific on the rise, The World Bank, 11 May 2012, blogs.worldbank.org/eastasiapacific/four-years-on-what-china-got-right-when-rebuilding-

after-the-sichuan-earthquake. “China - Natural Disasters.” GOV.UK, GOV.UK, www.gov.uk/foreign-travel-advice/china/natural-disasters. “Japan.” The World Factbook, Central Intelligence Agency, 31 Oct. 2017, www.cia.gov/library/publications/the-world-factbook/geos/ja.html. “Japan - Natural Disasters.” GOV.UK, Open Government License, www.gov.uk/foreign-travel-advice/japan/natural-disasters. Phillips, Tom. “The children airbrushed from the story of China's devastating quake.” The Telegraph, Telegraph Media Group, 11 May 2013, www.telegraph.co.uk/news/worldnews/asia/china/10051077/The-children-airbrushed-fro m-the-story-of-Chinas-devastating-quake.html. “Population Pyramids of the World from 1950 to 2100.” Population Pyramid, www.populationpyramid.net/japan/2050/. “Population, Total.” The World Bank, The World Bank Group, 2017, data.worldbank.org/indicator/SP.POP.TOTL?locations=CN. “Reconstruction.” The Great Kantō Earthquake of 1923, 2013, www.greatkantoearthquake.com/reconstruction.html. Schencking, J. Charles. “The Great Kanto Earthquake and the Culture of Catastrophe and Reconstruction in 1920s Japan.” Journal of Japanese Studies, vol. 34, no. 2, 2008, pp. 295–331. JSTOR, JSTOR, www.jstor.org/stable/27756570. Wyss, Max. "Evaluation of proposed earthquake precursors." Eos, Transactions American Geophysical Union 72.38 (1991): 411-411....