earthquakes reflection 2- plate tectonics

what ideas supported Wegener’s idea of continental drift

jigsaw puzzle fit of continents, linked fossil patterns across continents, paleoclimate indicators like glacier movement, matching geologic units of age and composition

The energy that drives Plate Tectonics and is responsible for earthquakes and volcanic eruptions comes from

the Earth's internal heat energy from the core and mantle

describe earth’s lithosphere

cold, rigid, strong, solid

all plate boundaries are associated with

presence of earthquakes

what features are associated with subduction zones

volcanoes, trenches, plates subducting into mantle, large earthquakes

what do you find at divergent plate boundaries?

volcanoes and mostly small earthquakes

the Himalayas are at what plate boundary

continent-continent convergence

The point on Earth's surface directly above the point where an earthquake occurs

epicenter

_______ travel the fastest of energy waves produced by earthquakes and can travel through _______, whereas _______ are slower and can travel through _______.

p-waves; solids, liquids, or gases; s-waves; solids

criticism of wegener’s work

couldn’t explain how or why plates moved

who provided mechanism for continental drift and how?

harry hess, national defense sonar

why did continents move apart?

seafloor spreading

where does magma come up to make new material

midocean ridges

youngest rocks are ___ , older rocks are ____ from the ridge

near, far

describe the magnetism pattern of earth

flips over time, symmetric, barcode pattern, iron points N vs S

inner core composition

solid iron ball

outer core composition

molten iron

mantle composition

silicate rock, peridolite, <3% melt (magma)

crust composition

silicate rock, granite, basalt, sandstone, shale, gneiss

lithosphere

rigid outer layer composed of crust and upper mantle

asthenosphere

beneath lithosphere, mostly solid, flows slightly

what melts rocks?

increased temperature, decreased pressure on hot rocks, chemical reactions with water

what happens during convection?

colder, denser rock from crust sinks; hotter, less dense rock from mantle rises

divergent plate boundary

how pangea broke apart, continental drift, not many volcanoes

convergent plate boundary- oceanic-oceanic

older, cooler, denser descends into subduction zone, volcanic islands on overriding plate

convergent plate boundary- oceanic-continental

denser oceanic crust subducts below continental crust, volcanoes/mountains form on continental plate, violent volcanoes and earthquakes

convergent plate boundary- continental-continental

2 continental collide, none go down, high mountains, no volcanoes

transform fault boundary

plates move laterally past each other between sea floor spreading centers, little volcanism, shallow, damaging earthquakes