Earthquakes & TsunamiBy Annie Cloutier

Earth & Space Sciences2015 copyright©

How do we measure earthquakes ?

Magnitude and Richter Scale

https://sincedutch.files.wordpress.com/2012/01/48-hours-in-earthquakes-magnitude-earthquake-jan-19-2012.jpg

Types of faults that cause earthquakes

Where do earthquakes happen ?

http://walrus.wr.usgs.gov/earthquakes/cencal/

San Francisco Earthquake

Where should I go during an earthquake ?Damage and Safety

://www.slideshare.net/EssayWriterCoUk/what-should-i-do-before-during-and-after-an-earthquake

Rickter Scale………

P waves > primaryS waves > secondary waves

L waves > lateral waves

Seismic waves through the planet Earth

P S L seismic wavesepicenter and focus

Surface waves behave like a pebble dropped in a still pond and do the most damage

Epicenter >

How can we make buildings more safe ?

Living on Cape Cod is not a “high risk” location for earthquakes, but, we have had a 3.5magnitude.

Highways,skyscrapers and bridges are safer now than in 1980

http://www.geo.mtu.edu/UPSeis/locating.html

http://pubs.usgs.gov/gip/earthq1/measure.html

http://earthquake.usgs.gov/learn/publications/saferstructures/

Tsunami Japanese for Harbor wave

http://eandt.theiet.org/magazine/2011/04/images/640_tsunami.jpg

When the seafloor drops down abruptly or is pushed up suddenly because of plate tectonic activity, the ocean

rushes in to fill the displacement gap of the Earth’s crust.

Sumatra 9.4 magnitude earthquake 2004 fourth largest earthquake ever recorded

Surviving a Tsunami

https://walrus.wr.usgs.gov/tsunami/sendai11/screen_shot.jpg

Displacement of ocean water rushes into void created by crust falling, generates tsunami wave

How do earthquakes generate tsunamis?

Tsunamis can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. Tectonic earthquakes are a particular kind of earthquake that are associated with the earth's crustal deformation; when these earthquakes occur beneath the sea, the water above the deformed area is displaced from its equilibrium position. Waves are formed as the displaced water mass, which acts under the influence of gravity, attempts to regain its equilibrium. When large areas of the sea floor elevate or subside, a tsunami can be created

Wave generation by sea floor earthquakes

Tsunami