27 August 2008 Lecture 1 Outline – Topic Preview 1 MAR 110 Lecture #1 Introduction to Oceans Hazards SECTION I – Volcano, Earthquake, and Tsunami Hazards Figure 1.2 Ocean Basin Rim Hazards - Volcanoes Volcanoes by the sea do explode creating ash that can bury a city and its inhabitants - Pompei, Italy and deadly tsunamis that can raise havoc many miles away (NG) Figure 1.1 Ocean Basin Rim Hazards - Earthquakes Earthquake-Induced Oil Storage Tank Conflagration – Valdez, Alaska.(NG)27 August 2008 Lecture 1 Outline – Topic Preview 2 Figure 1.3 Earthquake Distribution (Top)The location of shallow earthquakes (less than 100km deep); note how they silhouette both ocean spreading ridges and convergent zones. (Bottom) The locations of deep earthquakes are usually associated with plate subduction. (e,g, circled Sumatra earthquake – 26 December 2004) (?)27 August 2008 Lecture 1 Outline – Topic Preview 3 Figure 1.5 Lisbon Earthquake/Tsunami A tsunami wave generated by a earthquake in the Azores in 750 AD pummeled Lisbon, Portugal. Figure 1.4 Sumatra Tsunami 2004 The 26 December 2004 Sumatra tsunami: It’s origin and configuration in the Indian Ocean after 2 hr, 3.5 hr and about 10 hr. (NG Apr05)27 August 2008 Lecture 1 Outline – Topic Preview 4 Figure 1.6 Ancient Continental Configuration Pangaea: the continental configuration 200-300 million years ago showing how most of the present day continents were physically connected to each other into two super continents called Laurasia and Gondwanaland. Note the location of the even older (i.e., paleo-) equator at that time as well and its relation to of coal beds, which along with other geologic structures were used by scientists to determine how the continents were connected. (ItO)27 August 2008 Lecture 1 Outline – Topic Preview 5 Figure 1.7 Continental Drift A time series showing the configuration and movement (arrows) of the continents at (top) 200 million years ago; (middle) 65 million years ago; and (bottom) today. (?)27 August 2008 Lecture 1 Outline – Topic Preview 6 SECTION II – Hurricane Surge, Storm & Rogue Wave Hazards Figure 1.9 Hurricane Carol Visits Narragansett Bay 1954 (left) Hurricanes form in the eastern tropical Atlantic and (right) can move rapidly northward to surprise New England. (projo) Figure 1.8 Plate Tectonics Dynamics A schematic of the major plate tectonic features in the upper 450km of the Earth. Convection in the Asthenosphere, under the ocean ridge, causes the lithospheric plates to pull apart in the divergent zone, move in opposite directions across the ocean basin, collide with the adjacent plate in a convergent zone, and subduct to great depth. The subducting lithosphere melts at depth and rises as magma to form a volcanic island arc. (ItO)27 August 2008 Lecture 1 Outline – Topic Preview 7 Figure 1.11 Hurricane Surge Destruction (above) The storm surge and waves of the Hurricane of 1938 lifted the cottages with people in them off their foundations in Watch Hill, RI (bottom) and swept them away. (sst) Figure 1.10 The Great New England Hurricane -1938 The track of the September 1938 hurricane. Multiple ship reports allowed meteorologists to reconstruct the trajectory after it struck Long Island and New England without warning on 21 September. (projo)27 August 2008 Lecture 1 Outline – Topic Preview 8 Figure 1.13 Rogue Waves (left) The Great Wave by Katsushika Hokusai (1830) was “inspired” by serious tsunami impacts on Tokyo Bay; with geography that amplifies tsunami waves more than would usually be expected. (right) Unexpected waves with heights exceeding 100ft – “rogue waves’’ can imperil ships (?) Figure 1.12 Storm Waves Waves generated by winds at sea can travel long distances to cause great coastal destruction. (?)27 August 2008 Lecture 1 Outline – Topic Preview 9 SECTION III - Climate Change Hazards Short-Term Changes – El Nino Figure 1.15 El Nino-Related Destruction (left above) East to west winds normally trap the warmer surface waters of the tropical pacific to the west. (left below) However, the winds change every 3-7 years allowing the warm water to ‘race” to the eastern side of the ocean – changing the climatic conditions when they do. (right) In the case of Peru, storms are more frequent, more rain falls causing flooding and economic hardship. Figure 1.14 El Nino-Related Destruction (NG Nov76)27 August 2008 Lecture 1 Outline – Topic Preview 10Long-Term Changes Figure 1.16 Long-Term Climate Change (above) Glacial cycles with their associated major temperature changes occur over time scales ranging from 10,000 to 100,000 years. (below) Some scientists believe that glacial cover was extreme at a time 100 millions of years ago.27 August 2008 Lecture 1 Outline – Topic Preview 11 Figure 1.19 The Titanic On April 12, 1912 the Titanic hit an iceberg and sank in the North Atlantic Ocean taking most of the crew and passengers aboard with it. That year had been one of an unusually large number of icebergs traveling much farther south than they had in previous years. (?) Figure 1.18 Arctic Melting The shrinking of the arctic polar ice between (top) 1979 and (bottom) 2003. Significant melting occurred, reducing the ice cover by about half in only twenty four years. (NG ????) Figure 1.17 Greenhouse Gas Buildup CO2 concentration measurements on Mona Laua, HI between 1950 and 1995 showing a general increase. The annual CO2 uptake by continental vegetation is reflected by the saw tooth form. (UWaC)27 August 2008 Lecture 1 Outline – Topic Preview 12 Figure 1.20 Tipping Point ? Figure 1.21 Greenhouse Gas Buildup CO2 concentration measurements on Mona Laua, HI between 1950 and 1995 showing a general increase. The annual CO2 uptake by continental vegetation is reflected by the saw tooth form.