earthquakes midterm 1 study guide

earthquakes midterm 1 study guide - Lecture 1 Radioactive...

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Lecture 1 Radioactive isotope – occurs at constant rate independent of temperature or pressure Half life – divide by 2 Age of the Earth – 4.6 billion years old, determined by dating meteorites Age of rocks – use isotope that has a big enough half life (uranium) Oldest continental rocks – occur at the center of continents, Greenland Oldest oceanic rocks - .2 billion years old Power of ten notation – 10 9 = 1,000,000,000 Ages of sun and other planets – all 4.6 billion years Age of universe – 13.6/ 15 billion, we know that because universe is expanding Lecture 2 What is an earthquake – sudden slip in fault plane Fault plane – place of weakness around a fault trace Fault trace – surface line, intersection between the fault plane and the earth’s surface Fault scarp – a cliff or steep slope formed by displacement of the ground surface Hypocenter (focus) – point where earthquake starts (lat, long, depth) Epicenter – point directly above hypocenter on the earth’s surface (lat, long) Where earthquakes occur – at plate boundaries 3 types of plate boundary diagrams divergent – two plates moving apart, mid-ocean ridges convergent – one plate moving up, one moving down, against each other, trench/island- arc structures transform – sliding against each other, San Andreas Fault, fracture zones linking sections of mid-ocean ridges. Plate tectonics – anything that raises topography (earthquakes, volcanoes, mountain building) Lithosphere – the outer, rigid shell of the earth above the asthenosphere, contains the crust, continents, plates, and uppermost mantle Asthenosphere – layer below the lithosphere, it is the weaker, hotter, deeper part of the upper mantle Mantle Convection – slow motion of earth’s mantle in response to its variations in density, causes earthquakes and tectonics Hot spots – place on earth’s surface where hot mantle is stirring below, where active volcanism has occurred for a while where magma comes up, ex - Hawaii Continental Collisions – subduction zone is destroyed, mountains are produced, two continents are sutured together, ex - Himalayas Nature of seismicity at each type of plate boundary. Divergent – two tectonic plates moving away from each other, mid-ocean ridges
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earthquakes midterm 1 study guide - Lecture 1 Radioactive...

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