By Candy Olson

Fault lines = relief of stressSubduction: normal faulting reverse faulting strikeslip transformhttp://www.iris.edu/gifs/animations/faults.htm

tsunami

http:/www.pbs.org/wnet/savageearth/animations/tsunami/main.html

Danger -Getting knocked about by debris -Being pulled out to sea

Observed phenomena Gas clouds-can be irritating, fatal, eclipse the

skyLightningHaze –before, during and after a quakeWater/steam geiserSand, coal or other mineral geiserLand splits, drops, or raises

seismographMeasurements1st in China@135 C.E.Han dynasty-invented by Chang Heng

1st modern day seismograph in 1875 by Cecchi in Italy –used a suspended pendulum

Work was done in 1880’s in Japan that continued to improve on Cecchi’s work

http://earthquake.usgs.gov/learning/kids/kidsLearningLinks.php

Types of measurementRichter scale: measures movement of

suspended pen (seismograph) during a quakeSeismic moment: measures how much and

how far the Earth’s crust moves during a quake

Types of earthquakes

Benioff zone- focus is deep in subduction zone

Surface- focus is at or near the surface of the Earth’s crust

http://www.pbs.org/wnet/savageearth/animations/earthquakes/index.html

How do scientists know where the focus is?

One station recording a quake gives a circle of possibilites.

Two stations give two possibilities.Three stations finds the location of the

epicenter.Four stations finds the depth/ focus.

Scientific advancement from studying earthquakes:

Have learned that entire plates can shake in a great quake;

Are learning what the interior of the Earth is made of/how it’s arranged.

Are learning the geological history of the Earth.

Lab activityhttp://web.ics.purdue.edu/~braile/edumod/

slinky/slinky.htm