Plate Tectonics II:Volcanos and Earthquakes and Tsunamis, Oh

My

Dr. Mark McGinleyHonors College and Department of Biological

SciencesTexas Tech University

Evidence for Plate Tectonics

Evidence of Plate Tectonics

http://www.mnh.si.edu/earth/text/4_1_2_3.html

Evidence of Plate Tectonics• 1980s• Ten years of telescope-based

measurements from Earth to distant quasars confirmed that the North American and Eurasian Plates are moving away from each other at a rate of 1.7 cm (0.7 in) per year.

• Geological studies of ocean-floor rocks suggest the plates have moved at this same average speed for tens of millions of years.

Evidence for Plate Tectonics

• Two telescopes — one in Massachusetts, the other in Germany — measured their distance to a pulsing quasar at the same time. This measurement was repeated 803 times over 10 years. Each point on the graph indicates how far apart the two stations were at that time. As you can see, they slowly moved apart.

Plate Tectonics and Volcanos• A volcano is an opening,

or rupture, in a planet's surface or crust, which allows hot magma, volcanic ash and gases to escape from below the surface.

• Volcanoes are generally found where tectonic plates are diverging or converging.

Volcano

• http://www.youtube.com/watch?v=DceHEBGVfj4

Volcanos and Divergent Plate Boundaries

• A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by divergent tectonic plates pulling apart

Volcanos and Convergent Place Boundaries

• http://geology.com/nsta/convergent-plate-boundaries.shtml

Volcanos and Convergent Plate Boundaries

• The Pacific Ring of Fire has examples of volcanoes caused by convergent tectonic plates coming together.

Volcanic Islands

• Not all volcanos occur at plate boundaries

• Hot spots, locations of rising hot magma, can cause magma to reach the surface causing volcanos

Formation of the Hawaiian Islands

Snake River HotspotsYellowstone

Earthquakes

• An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves.

• The seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time.

Earthquake Locations

Plate Boundaries

Earthquake animation

• http://www.youtube.com/watch?v=30SFfPvcss0

1989 San Francisco Earthquake

• http://www.youtube.com/watch?v=zkx-vO9I8r8&feature=related

Tsunami

• A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake.

• Earthquakes, volcanic eruptions and other underwater explosions, landslides, glacier calvings, meteorite impacts and other disturbances above or below water all have the potential to generate a tsunami.

2004 Tsunami

• http://www.youtube.com/watch?v=4Xebwzb3dDE

• http://videos.howstuffworks.com/discovery/14049-tsunami-2004-indian-ocean-plate-shift-video.htm

Video Tsunami 2004

• http://www.youtube.com/watch?v=EEzt3DXOHWI

2011 Japanese Tsunami

• http://video.nationalgeographic.com/video/news/environment-news/japan-tsunami-2011-vin/