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Earthsci Week 1.docx

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Earth Sciences
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Earth Sciences 2240F/G
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Introduction The Scientific Method  Observations  form a hypothesis  Test hypothesis using more and more observations, and they will either suggest that the hypothesis is correct, or that a new one is needed  Theory is developed from the successful hypotheses. As long as all the tests pass, you can make predictions of the end-result  After very long and always successful testing of the theory, it will be reworded into law Terminology and Statistics  Natural processes: events directed by physical, chemical, and biological activity (earthquakes, volcanic eruptions, hurricanes) o They do not become natural hazards until they are a threat to life or property o There are many natural hazards, but they don’t need to be disaster or catastrophe o Commonly, disasters occur because of a careless appraisal of a natural hazard  We can’t control natural hazards, we simply work at predicting them and reducing their efforts o Assessing risk, looking at precursor signs  Natural disaster: a sudden misfortune/ calamity  local scale  Natural catastrophe: widespread disaster, an event subverting the system of things, a disastrous end  regional or global scale o Local disaster: a significant disruption to local society and communities, but the consequences are contained locally o Regional disaster: magnitude is greater, more widespread o Regional catastrophe: a disruption of sufficient magnitude that large regions must deal with consequences, including death and numerous injuries to the regional population o Global catastrophe: the magnitude of the disruption is felt and dealt with on a global scale, death of many whole species is common  Mexico City 1985: earthquake, regional disaster  China, city of Tanshan, 1976: earthquake, regional catastrophe  Indian Ocean tsunami, 2004: global catastrophe The Rising Cost of Natural Disasters and Catastrophes  In 1950, the average cost of hazardous processes was 3.9billion per year, and there has been an almost steady increase in cost in recent years o The population has greatly increased, and many more have chosen to live closer to known potential hazards (ex. slopes of volcanoes, fault zones)  Global climate models predict that a warmer climate will lead to higher sea levels, coastal flooding, more intense storms, heat waves …etc. Earth’s climate has always changed, but recently humans have been forcing some of that change  There’s an apparent trend upward with time, more natural disasters in later years from1950- 2005. Climate change? Other reason that makes relatively normal events now deadly in later years?  The Population Bomb: at the current rate, the world will have 384 billion people by 2300 (Earth will never have the resources to sustain this) o More people are affected by natural disasters today because there are more people in the world to be affected o More expensive infrastructure in natural disaster-prone areas  The human population was neither abundant nor widespread before modern times, and natural hazardous processes seldom were catastrophic to our species Extinction Catastrophes  The Mother of all Extinctions: 251 million years ago, wiped out about 96% of all species on Earth Chapter 1: Philosophy: Problems with Observation and Interpretation  Early science: many competing methods, theories and systems, no separation between science and religious dogmas, and no consensus on how scientific theories could be evaluated, no correct scientific procedure 1. Geology and Religion  The major 18 century challenge to orthodox religion and traditional order came from geology, and more specifically the idea of evolution  Nicolaus Steno (1638-1686), Danish natural philosopher: sought to reconstruct the history of Earth’s surface on the basis of the processes he could see happening (weathering, sediment transport, layered sediment). In what way does the present condition of anything disclose the past condition of the same thing? o Steno’s theory was the Earth had a very different surface than the one now, and that the original surface was a smooth pile of sediments o Relied heavily on field work, in Italy he recognized the marine origin of fossils. He published his history in short text in Latin o Steno is the ‘father of stratigraphy’, the study of the layers of rocks and sediments. Hutton gets the label of ‘father of modern geology’ o In 1667, Steno converted to Roman Catholicism and ceased his geologic work  Thomas Burnet, Anglican clergyman, confessor to King William III: assumed a literal translation of creation as told in the bible, and so assumed all the uneven features of the Earth resulted from Noah’s flood (water came from inside the Earth, and then went back there when the flood was over) o Burnet published his ideas in 4 volumes: none of it makes sense now, but at the time it was praised, and Steno’s work was dismissed  Religious right was strengthened, and so it was essential that all astronomical, geological and biological hypotheses had to be reconciled with a literal interpretation of the bible o Archbishop Ussher (1650) calculated that Earth came into existence at sunset of nd October 22 , 4004 B.C. using dates in the Bible  no fault in his calculation Catastrophism  Catastrophism: an attempt to recognize the importance of geological processes, but sequence them and confine them within the concept of biblical studies  Baron Georges Cuvier (1769-1832), head of the Academy of Science in Paris, related to Royalty and hugely influential: published the results of his study of the sedimentary rocks forming the layers of the Paris Basin o He saw repeated series of layers of boulders above layers of fine-grained sands, and interpreted this as repeated stages of sudden flooding had occurred here o He also claimed that the only mechanism for the flooding was a series of huge catastrophes that were sudden, violent, and completely unpredictable  the final flooding was Noah’s flood, and the earlier ones were mythological accounts from other cultures o He placed creation at 6000 years in the past, fitting Bishop Ussher’s calculations o His detailed geological mapping and drawings were useful, but he ‘never lost faith’ and would disregard features that called into question literal interpretations o Cuvier discovered a mastodon skeleton, and saw the similarities between those and an elephant, but thought considering it evolution was not morally correct  If you were a catastrophist, you believed that: o The history of Earth was a record of unique events o That there was no such thing as natural evolution of anything o No possible prediction of nature  Catastrophists assumed that  exam question! o Earth began as a molten ball o As it cooled it went through a series of intermittent global convulsions that threw rocks into mountain formations (even those containing marine fossils) o Valleys were the erosional signal of Noah’s flood o Fossils represented previous life forms that were killed off during the episodic catastrophic events o There were no biological connections between any species, all were independent creations Uniformitarianism or Gradualism  Uniformitarianism/ gradualism: opposite philosophy of Catastrophism  Leonardo da Vinci was the first to have recognized the concept, but didn’t name or develop it. The first serious application to geology was the work of Steno in the mid- to late- 1600s  The first person to formulate the con
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