**** REVIEW MONDAY, APRIL 28TH; 6:00-8:30 PM; WEBSTER 16Chapter 18: Amazing Ice: Glaciers and Ice Age Video notes:o The Little Ice Age – most recent big chill 14th – 19th century Volatility of climatic shifts – no logic or cycle; no constant cold Beer > wine! Avg. 4 degrees cooler than avg. today; dropped within a decade- Catastrophic to the vulnerable society of the 13th century Natural record:- Cores of sea floor – 2”-4” represent 1,000 years END: 1850- Course of a decade- Disagreements about how it endedo Theory 1: increased sun radiationo Theory 2: fewer volcanic eruptions and industrialization (greenhouse gases)o Theory 3: natural fluctuation of the ocean Current oscillates in strength Weak cycle caused Ice Age; strong cycle brought it to an endo Little Climate Optimum One of greatest ages of prosperity 4-7 degrees warmer than The Little Ice Age 13th century feudalismo Last major Ice Age before that – 10K years agoo 1693 French Alps – major glacial movement; wiping out villageso 1371-1791: 111 famines Died of famine-related diseases (e.g. bubonic plague) Burned people at the stake because they believed they were the ones inciting the weathero Theory 1: Sun was at 0.5% less output than normal; any little change can cause Earth to go nutso Theory 2: Sulfur deposits in ice cores – 5 major volcanic eruptions each century All with 1883 Krakatoa’s power Thin, hazy cloud around Earth – less sunlighto Theory 3: Thermohaline Current Surface waters get warm in tropics, flow North, cool and flow down again Believe natural forces (floor of fresh water from artic ice that melted during Medieval Warm Period) caused disruption in current “conveyor stops” – no more heat over northern Atlantico 1815: single-most powerful eruption; “The Year Without A Summer” Sumbawa, Indonesia – Mt. Tambora 2’ snow in New England 75% of corn died Helped push America Westo Theory 1: global warming may cause another Ice Age Melting glaciers – freshwater flood and shutdown of conveyoro Theory 2: global warming may cause another Ice Age BUT it will all cancel itself out and will end up getting warmer rather than cooler…o *** change in adaptation that causes chaoso Pentagon Scenario 10 years: rapidly drained of food, energy, etc. crucial for survival U.S. becomes global government and military Mass migration to U.S. China: famines and drained energy supplies; civil war erupts World War III eruptsChapter 8: Earthquakes What is an earthquake? (cont.)o Fault scarp : cliff from vertical slip on faulto Aftershocks : smaller earthquakes that follow an initial earthquake in same vicinityo Foreshocks : smaller earthquakes that sometimes precede a larger one by a few days Seismic Waveso The strain energy released by an earthquake is transmitted through the rocks in all directions in the form of waveso Seismology is the study of earthquakeso Body Waves P-Waves (primary/pressure)- Waves expand and contract (compressional) – push/pull- Fastest wave (~6-7 km/sec; ~4mi/sec)- Travel through liquid, solid, or gas S-Waves (secondary/shear)- Waves move up/down, side to side- Slower than P wave (~3.5 km/sec; ~2 mi/sec- Travels through solid only Both travel straight through the mantelo Surface Waves Slowest wave (~2.5 km/sec; 1.5 mi/sec) travel along surface of the earth Side to side (Love wave) Up and down (Rayleigh waves) Travels through solid only Trees sway wildly Some people have seen waves in the groundo Measuring Earthquakes: Seismograph : device that records seismic wave motion- Difference of S-waves and P-waves gives us distance we are from epicenter- 3 seismograph stations to determine location of epicenter (triangulation) Seismogram : record of shaking 3 scales:- Modified Mercalli scale :o based on relative destruction and observations by peopleo delineates 12 intensity levelso different rates based on ground material- The Richter scale :o Scale of 1-10o Based on max amplitude of S-wave on seismogram, each number represents 10x the shaking powero 33x increase in energy released with each numbero Developed for CAo Uses the max amplitude to determine the earthquake’s magnitude at a standard distance from the earthquake epicenter (100km)- Moment magnitude scale (M M):o Depth of faulto Total amount of slip (movement) on faulto Strength of rock typeo The Richter and Moment magnitude produce roughly the same numerical values, the moment magnitude scale is preferred by