Article summary of Robert M. Hazen: Lifes Rocky Start - Essay Example

Robert M. Hazen: “Life’s Rocky Start Summary of the Article. The article, “Tsunami: Wave of Change,” by Eric L Geist, Vasily V. Titov and Costas E. Synolakis explores the various angles of the December 2004 Indian Ocean tsunami, which caused catastrophic damage, and analyses the ways in which the data collected from this event can contribute to the improvement of computer models which forecast tsunamis. The magnitude of the disaster, which resulted in the loss of 225,000 lives, and displaced millions, emphasizes the threat posed by tsunamis. The significant volume of data generated has reshaped the scientific perspective towards tsunamis. The December 2004 tsunami, coupled with the subsequent March 2005 tsunami, has alerted researchers to broaden their definition of potential danger areas, provided an opportunity for testing the accuracy of computer simulations which forecast tsunamis, generated additional information on the on-shore effects of the waves, and cast new light on the effect exerted by earthquakes on tsunamis. Researchers have marked the potential danger areas of tsunami-generating earthquakes. These areas are subduction zones, where the earth’s tectonic plates collide. It is the sudden release of the built-up stress in the fault line between two plates which causes an earthquake. The earthquake causes further tectonic shifts, with one plate thrusting upon the other, leading to displacement of the sea floor. This generates the tsunami. The giant tsunami of December 2004 occurred in the Sumatra-Andaman region, which did not fall into a well-known, normal subduction zone. Based on this, scientists are now reassessing the threat potential of similar slow, or clogged, subduction zones, such as Alaska and Puerto Rico. The wealth of data generated from the December 2004 tsunami has contributed to a better understanding of how tsunamis begin, build up and behave onshore, and to the development of improved computer models that forecast tsunamis. Over the last two decades, researchers in the US and Japan have built computer models which simulate the progression of a tsunami in the open ocean. These tsunami-propagating models are based on two starting variables: an estimation of the area and location of the fractured sea floor, and the height of the displaced water. These variables have remained merely theoretical, as they could not be validated through actual observations. The earlier tide gauges and estimations of on-shore damage provided only approximate measures of these variables. The December tsunami was monitored by satellites which provided exact, continuous measures of wave heights, and confirmed the validity of current simulation models. The National Oceanic and Atmospheric Administration’s simulation was able to demonstrate that mid-ocean ridges are responsible for spreading wave energy. Researchers have gathered a better idea of the on-shore effects of tsunamis. These effects could not be accurately calculated and predicted by earlier computer models. The current models were compatible with the inundation patterns of past tsunamis. The December 2004 tsunami proved that these models were also accurate in the case of large tsunamis, even in the absence of data on coastal topography. It also demonstrated that flood water depth was not the only variable in forecasting the destructive capability of a tsunami. It showed that the ability of the waves to destroy reinforced concrete structures which have withstood earthquakes is due to the powerful currents present in tsunami floodwaters. The effect of earthquakes on tsunamis could be better analyzed through the direct measurement of tsunami wave amplitude. These accurate measures enabled the improved analysis of the fault slips which cause a tsunami to aggravate in strength. However, the wave height observed by satellites and the extreme flooding in Sumatra could not be matched by the tsunami models which incorporated this seismic data. It was then discovered through GPS measures that it is the after-slips of a fault which cause high magnitude tsunami waves. The March 2005 earthquake, although of great magnitude, did not generate tsunamis of the strength of the December event. This is attributed to the fact that the March earthquake struck a deeper part of the fault and less energy travelled to the overlying water. It occurred in shallower water so that there was less water to be displaced. Its origin was located below islands, causing most of its energy to be blocked by land masses. Geist, Titov and Synolakis assert that the improved computer models made possible by the data generated by the December 2004 tsunami will contribute towards the development of new monitoring and warning systems which will significantly enhance the ability of scientists to forecast tsunamis and reduce the damage caused to human life. 2. Discuss one aspect of the article you understood well. At the start of their article, Geist et al. give a concise and very easily comprehensible account of how earthquakes and tsunamis are generated. The subduction zones underneath the oceans, with their deep trenches, are the birthing grounds for tsunamis. Tectonic shifts lead to the collision of plates and stress builds up across the interface between the two plates. This stress is released during earthquakes. The top plate is pushed upward, forcefully displacing the water above it. This displaced water forms the monster waves of the tsunami. 3. Discuss one aspect of the article you did not understand well. In spite of frequent references to laboratory models and computer simulations of tsunamis, the authors do not give any clear explanation of what exactly these models are comprised of. What is a computer simulation of tsunami behavior? What variables does it include? Another concept I am not very sure I can grasp is that of fault slips and after-slips. If after-slips stop emanating seismic energy, why do they continue to contribute to the height of the tsunami waves? 4. Discuss what about the article you found most interesting or informative. On reading the article on the catastrophic effects of the December 2004 tsunami, I am constantly reminded of nature’s unbridled power. In spite of science’s advances, nature can unleash forces beyond the control of man and all his machines. However, it is inspiring to see how dedicated researchers, such as the authors of this article, are engaged in understanding and combating complex natural phenomena. I found the list of factors that contribute to the force of tsunamis to be very informative. Just a few differences, based on the comparative origins of the two earthquakes in December 2004 and March 2005, were responsible for the great differences in the strengths of the two tsunamis. Geist, Titov and Synolakis make a very compelling case for the necessity of implementing the new tsunami science in all vulnerable areas of the earth on a war footing. It is tragic to know that if the Indian Ocean had been equipped with the necessary tsunameters which are in place in the Pacific Ocean, the catastrophic loss of human life could have been avoided, or at least reduced. The disparity between the developed and developing world should not be a factor in gaining access to life-saving technology. Works Cited. Geist, Eric L, Vasily V. Titov and Costas E. Synolakis. “Tsunami: Wave of Change.” Scientific American. January 2006. p. 56-63. Print. Read More