Download PowerPoint - Science A 2 Z

By Candy Olson
 Fault lines = relief of stress
 Subduction:
normal faulting
reverse faulting
 strikeslip
 transform
 http://www.iris.edu/gifs/animations/faults.htm
tsunami
 http:/www.pbs.org/wnet/savageearth/animations/tsu
nami/main.html
Danger
-Getting knocked about by debris
-Being pulled out to sea
Observed phenomena
Gas clouds-can be irritating, fatal, eclipse the sky
Lightning
Haze –before, during and after a quake
Water/steam geiser
Sand, coal or other mineral geiser
Land splits, drops, or raises
seismograph
 Measurements
 1st 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/kidsLearnin
gLinks.php
Types of measurement
 Richter scale: measures movement of suspended pen
(seismograph) during a quake
 Seismic 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/eart
hquakes/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 activity
 http://web.ics.purdue.edu/~braile/edumod/slinky/sli
nky.htm