Natural Disasters Introduction

1. Natural DisastersIntroduction

2. Focus of this class Learn about natural disasters, and the geologic processes that are responsible Examine how natural disasters affect us

3. What Is Science? Science is a systematic process of asking questions about the observable world and then testing the answers to those questions.

4. What is a Natural Disaster? An event of nature that releases energy upon an area, causing destruction of property and loss of human life.

5. What is a Natural Hazard? A hazard that arises from geological or weather-related occurrences. Includes: Earthquakes Volcanoes Floods Storms / Hurricanes / Tornadoes

6. Terms to Know Magnitude - The size of the event Frequency- How often the event happens Return Period- The time between two events of the same size

7. Terms to Know Disaster- A natural event, such as a flood or earthquake. Catastrophe - A natural event that causes significant damage to property and harms/kills a large number of people.

8. Terms to Know Hazard - Occurs when a natural event is likely to cause harm Risk- Hazard + recurrence interval + costs great hazard potential + short recurrence interval + high cost = high risk

9. The Scientific Method Scientists assume the natural world is • Consistent • Predictable Our goal: Discover patterns in nature Use these patterns to make predictions

10. The Scientific Method

11. Losses from Natural Disasters

12. Worst Disasters: Floods Hurricanes Earthquakes Severe Weather Least: Tsunami Volcanic eruptions Losses - Human Fatalities Why?

13. Losses - Human Fatalities Amount varies from year to year The population density of a region affects number of fatalities

14. Losses - Economic Sources: • Buildings, structures • Industry & businesses

15. Losses - Economic Insured Portion of Economic Losses Amount covered by insurance Dollar amount lost is different than lives lost

16. Developed Countries More insurance Expensive buildings Less loss of life Underdeveloped Countries Less insurance Inexpensive buildings More loss of life Losses - Economic

17. How Do Natural Disasters Originate? Transference of energy from one location or state to another • Internal Sources of Energy • Impact energy from the formation of the planet • Gravitational energy • Radioactive Elements/Internal Heat • External Sources of Energy • The Sun • The Hydrologic Cycle

18. Earth as a System Earth is a small, self-contained planet All parts of the Earth interact with one another Open vs. closed systems

19. The Four “Spheres” of the Earth Lithosphere Atmosphere Biosphere Hydrosphere

20. Atmosphere Gases for respiration Circulation – mod temperature Weather Hydrosphere Water for life Erosion of lithosphere Weather Biosphere Life! Respiration – O2, CO2 Decomposition - H2O, CO2 Organic Matter Erosion of lithosphere Uses water Lithosphere Erosion → “salts” for ocean → soil for plants “Holds” water for future use

21. Origins & The Formation Of The Universe

22. In the beginning . . . . . . There was the “Big Bang” Incandescent gasses, no matter yet Eventually, cooled enough to form simple elements (H+, He) Stars formed, then died (supernovae)

23. The Nebular Hypothesis Exploding star creates incandescent cloud of gasses & elements (aka a nebula) Nebula begins to rotate

24. The Nebular Hypothesis Gravity concentrates matter towards the center, forms a “proto-star” Dust-sized particles begin to smash together to form larger particles

25. An artist's conception shows the disk of dust and gas surrounding a young, whirling star. A new study suggests that turbulence helps, not hinders, such dust coalesce into planets by providing vortices where material can gather and grow. Source / Image courtesy NASA/JPL-Caltech

26. A still image from an artist's animation shows a pulsar—the rapidly rotating core of a dead massive star—surrounded by a disk of debris from the star's explosion. Scientists announced today that they found such a disk around a pulsar 13,000 light-years from Earth and that the debris could eventually clump together to form planets. Source / Image courtesy NASA/JPL-Caltech

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28. The Nebular Hypothesis As particles continue to collide with one another, they generate friction & heat Heatmakes the particles melt and fuse together Larger and larger particles coalesce

29. The Nebular Hypothesis All planets formed via the accretion of particles Initially: Larger than they are today Homogeneous in composition Molten rock

30. Why is the asteroid belt here? The solar system

31. 4.6 5 4 3 2 1 0 Billions of years before present PROTO-EARTH Thin, hard shell Molten inside LOTS of volcanic activity Outgassing formed first atmosphere Image source

32. 4.6 5 4 3 2 1 0 Billions of years before present PROTO-EARTH Particles still whizzing about the solar system Meteor impacts add material and heat to the planet Image source

33. 4.6 5 4 3 2 1 0 Billions of years before present Formation of our Moon Something the size of Mars collided with Earth • Object got stuck inside Earth • Debris encircled the Earth, eventually formed our moon QuickTime animation

34. The grazing impact of a Mars-size body with the proto-earth more than four billion years ago is believed to have led to the formation of our moon. Artwork by Joe Tucciarone, commissioned by Astronomy magazine.

35. Time series of a Moon-forming impact simulation From the following article: Origin of the Moon in a giant impact near the end of the Earth's formation Robin M. Canup and Erik Asphaug Nature 412, 708-712(16 August 2001) doi:10.1038/35089010

36. 4.6 5 4 3 2 1 0 Billions of years before present Formation of the Solar System (revisited) So, NOW what do you think caused the formation of the asteroid belt?

37. 4.6 5 4 3 2 1 0 Billions of years before present Formation of our Moon Evidence? • Our core is very large • Similar composition to iron meteorites • Moon is similar in composition to Earth

38. 4.6 5 4 3 2 1 0 Billions of years before present Formation of Layers within Earth Radioactive elements + Thermal contraction = Density stratification

39. 4.6 5 4 3 2 1 0 Billions of years before present Formation of Layers within Earth

40. 4.6 5 4 3 2 1 0 Billions of years before present Formation of our Atmosphere First atmosphere formed from outgassing Solar radiation stripped away initial atmospheres (also blew away remains of nebular gases)

41. 4.0 5 4 3 2 1 0 Billions of years before present Formation of our Oceans Outgassing formed hot clouds Eventually cooled, first (hot) rains fell Then what?

42. 4.0 5 4 3 2 1 0 Billions of years before present Formation of our Oceans Rains: Cooled the surface of Earth Began to erode the surface rocks Formed first oceans Rains may have lasted as long as 25 million years. Water may have covered the Earth’s surface for 200 m.y.!

43. 4.0 5 4 3 2 1 0 Billions of years before present Formation of our Oceans Erosion of surface rocks: “locked” CO2 into rocks Formed first salts in the oceans Ocean salinity nearly constant over past 4 billion years

44. 3.5 5 4 3 2 1 0 Billions of years before present Formation of our Atmosphere (revisited) Atmosphere began to change towards present due to: • Breakdown of crust into sediments to form ROCKS • Release of oxygen by the ancestors of green plants (2 billion years ago) How did this happen?

46. 3.5 5 4 3 2 1 0 Billions of years before present Origins of Life on Earth Hypothesized that life began in oceans Evidence: • All KNOWN organisms need water to survive • All of the earliest fossils are found in marine rocks

47. Twin “Black Smokers” source /Photograph by Emory Kristof Pale pink eelpout fish , white brachyuran crabs and blood-red tube worms source /Photograph by Emory Kristof White brachyuran crab source /Photograph by Emory Kristof

48. 3.5 5 4 3 2 1 0 Billions of years before present Earliest Lifeforms Cyanobacteria from NW Australia (3.4 – 3.5 b.y.o)

49. 3.5 5 4 3 2 1 0 Billions of years before present Earliest Lifeforms Stromatolites: colonial structures formed by cyanobacteria and other microbes

50. Modern stromatolites, Shark’s Bay Australia, and a 2.2 billion year old fossil stromatolite from Michigan