Dynamic Earth Dr. Jennifer Wright

Shake, Rattle, ‘n Roll Plate Tectonics – the big picture, creation of the major geographic features of the Earth Layers of the Earth Plate Boundaries Earthquakes Volcanoes Impact Craters

Plate Tectonics – the big picture, creation of the major geographic features of the Earth

Layers of the Earth

Plate Boundaries

Earthquakes

Volcanoes

Impact Craters

Layers of the Earth Inner core Solid Fe, Ni Outer core Liquid Fe, Ni Creates magnetic field Mantle Magma, convection Crust Thinnest, coldest layer Plates!!

Inner core

Solid Fe, Ni

Outer core

Liquid Fe, Ni

Creates magnetic field

Mantle

Magma, convection

Crust

Thinnest, coldest layer

Plates!!

Plate Tectonics Framework for understanding most geographic features of the planet Mountain ranges, volcanoes, earthquakes Deepest point (Marianas Trench), Highest point (Mt. Everest) caused by plate interaction 3 kinds of plate boundaries Divergent Convergent Transform

Framework for understanding most geographic features of the planet

Mountain ranges, volcanoes, earthquakes

Deepest point (Marianas Trench), Highest point (Mt. Everest) caused by plate interaction

3 kinds of plate boundaries

Divergent

Convergent

Transform

Divergent Boundaries Are the result of “pulling” forces Have small earthquakes Create many normal faults Are usually on the opposite side of the plate from a convergent boundary

Are the result of “pulling” forces

Have small earthquakes

Create many normal faults

Are usually on the opposite side of the plate from a convergent boundary

Convergent Boundaries Collision of two plates Have all the large earthquakes 90% of all earthquakes happen here Ocean-continent collisions = subduction Explosive volcanoes Reverse faults

Collision of two plates

Have all the large earthquakes

90% of all earthquakes happen here

Ocean-continent collisions = subduction

Explosive volcanoes

Reverse faults

Transform Boundaries Are the result of parallel and opposite forces Have small to medium earthquakes earthquakes Create strike-slip faults Can cause streams to turn at right angles

Are the result of parallel and opposite forces

Have small to medium earthquakes earthquakes

Create strike-slip faults

Can cause streams to turn at right angles

Earthquakes Mostly happen on plate boundaries 90% happen on convergent boundaries Seismographs can record earthquakes from all over the world above 2.5-3 on magnitude scale Are a release of energy as two blocks move relative to each other Are measured on a logarithmic scale (multiply by 10)

Mostly happen on plate boundaries

90% happen on convergent boundaries

Seismographs can record earthquakes from all over the world above 2.5-3 on magnitude scale

Are a release of energy as two blocks move relative to each other

Are measured on a logarithmic scale (multiply by 10)

Volcanoes Mostly created by melting of oceanic plate in the subduction zone and by hot spots in the mantle Explosive volcanoes associated with dissolved gases (H 2 O) in lava Ex. Mt. St. Helen’s

Mostly created by melting of oceanic plate in the subduction zone and by hot spots in the mantle

Explosive volcanoes associated with dissolved gases (H 2 O) in lava

Ex. Mt. St. Helen’s

Impact Craters Far fewer visible impacts than other planetary bodies Atmosphere Oceans Erosion/deposition High velocity of impacts vaporize the meteor Chesapeake Bay was created by an impact ~36 million years ago Most earthquakes in the region today are due to settling from impact and glacial rebound Contamination by saltwater limits the freshwater available today

Far fewer visible impacts than other planetary bodies

Atmosphere

Oceans

Erosion/deposition

High velocity of impacts vaporize the meteor

Chesapeake Bay was created by an impact ~36 million years ago

Most earthquakes in the region today are due to settling from impact and glacial rebound

Contamination by saltwater limits the freshwater available today

Classroom Activities Plate Boundaries Plot earthquakes on maps Graph earthquakes based on depth, magnitude, and boundary type Earthquakes on convergent boundaries are deeper and larger For more advanced students, locate the epicenter using “Virtual Earthquake” Plot volcanoes to locate plate boundaries (convergent) and hot spots (Hawaii) Discuss the week’s planetary events in terms of potential human impact

Plate Boundaries

Plot earthquakes on maps

Graph earthquakes based on depth, magnitude, and boundary type

Earthquakes on convergent boundaries are deeper and larger

For more advanced students, locate the epicenter using “Virtual Earthquake”

Plot volcanoes to locate plate boundaries (convergent) and hot spots (Hawaii)

Discuss the week’s planetary events in terms of potential human impact