GEOS 212 1st Edition Lecture 4 Outline of Last Lecture Volcanoes: 1500 could erupt, ~20 erupting most of the timeOccur in four tectonic settings:o Spreading centerso Hot Spotso Subduction Zoneso Continents Pulling ApartTwo main types of volcanoes:o Shield Volcanoes:o On oceanic crusto Not steep sideso Basalt (high iron); very hoto Not explosiveo Not Hazardouso Lava flows (runny)Strato Volcanoes: o On continental crusto Steep sideso Andesite (lower iron), cooler, stifo Explosiveo Hazardouso Lava flows, ash/cinders, pyroclastic flowsDiagrams of Shield & Strato VolcanoesVideos of shield volcano eruptionso % of volcanoes below sea surfaceo Importance of Kilaueao Temperature of lava?o Key to forecasting eruptions?o Nature of magmao Nature of basalt (color, texture)Videos of stratovolcano eruptionsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o What else comes from volcanoes besides magma? o Pyroclastic flow made up of rock, ash, gaseso Nature of magmao Nature of andesite ash (color, texture)o How many potentially active volcanoes?o How many people live at risk from volcanoes?- Cascade volcanoes in Oregon & Washington- Eruption history of the Cascade volcanoes- Caldera eruptions- Currently active Volcanoes (http://www.geocodezip.com/v2_activeVolcanos.asp)Outline of Current Lecture- Review of volcanoes ~1500 could erupt (dormant), ~20 erupting today - Shield volcanoes versus stratovolcanoes, hazards, prediction, setting - Transform fault = 3rd type of plate boundary - Atlantic example - Pacific example - San Andreas fault = transform fault = North America-Pacific plate boundary - Animations of earthquake process = stick, build up stress, then slip - Earthquakes along San Andreas fault - Sizes (magnitudes) or earthquakes - Views of San Andreas fault - Earthquake history along San Andreas fault - Global Earthquakes - Sumatra & Japan earthquake & tsunami - Animations of Sumatra earthquake & tsunami - Global map of earthquakes, with pattern of size and depths - Perspectives on big earthquakesCurrent
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