Geology exam 2

Geology exam 2 - EXAM 2 Physical Geology Tsunami secondary effect from an earthquake At the coast is where it is stronger We cannot predict

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Tsunami : secondary effect from an earthquake. At the coast, is where it is stronger. We cannot predict earthquake, neither short nor long prediction. Sumatra early warning system: scientist of Sumatra island are going to install a tsunami warning system for the region worst hit by the last year’s Asian killer wave. Characteristics of the interior of the earth: velocity changes between the crust and the mantel (less dense to more dense). Wave observations: Primary waves are reflected due to density differences. Secondary waves are not observed on the opposite side of the earth. Mohorovicic discontinuity (Moho): the seismic discontinuity that marks the base of the crust. Central and Eastern US Earthquakes (CEUS) Earthquakes occur in: - Plate boundaries, 90%. - Within a plate (intraplate): weakness in the interior of a plate, 10%. Why earthquakes occur in an intraplate? : - Old fracture surface, faults. - Areas where molten rocks boundary is closer to the surface, thin crust. - Density differences between crustal rocks. Virginia: VA earthquakes are not directly associated to Plate Tectonics and also there is not plate boundary. It’s an intraplate. There was an earthquake in VA on 1897. Intraplate earthquake: earthquake that occurs along a fault within the stable region of a plate’s interior (SICR). Infrequent occurrence, poorly understood and difficult to study. Ex : 1811-12 in New Madrid, MO and 1886 in Charleston, SC and 2001 in India . Two of the largest earthquakes in CEUS: New Madrid (XI in scale) and Charleston. Measuring historic earthquake: - Intensity based on Modified Mercalli scale. - No seismograph data available. There is a 4 % probability that a CEUS earthquake would occur in 50 years from now. It would be a loss of 200$ billions and 2/3 of the losses would be due to interruptions in the study projects. Minerals: Naturally occurring, inorganic solid, specific chemical composition and definite crystalline structure. Ex: White Asbestos : - most common, 95 % of all asbestos. Blue Asbestos : 1% of all asbestos use. Hokie Stone is made up of the mineral calcite and dolomite. Elements of the class generally came from minerals. Banxite came from aluminum. Glass is not a mineral because is not crystalline. Asbestos is not a mineral
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This note was uploaded on 12/11/2009 for the course GEOS 1004 at Virginia Tech.

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Geology exam 2 - EXAM 2 Physical Geology Tsunami secondary effect from an earthquake At the coast is where it is stronger We cannot predict

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