Re: pinhole plate tectonics/physics question

Date view Thread view Subject view Author view Attachment view

From: Paul Doherty (pauld@exploratorium.edu)
Date: Thu Jun 24 2004 - 13:36:28 PDT 

Message-Id: <l0311072abd00ead8846a@[192.168.112.30]>
Date: Thu, 24 Jun 2004 13:36:28 -0700
From: Paul Doherty <pauld@exploratorium.edu>
Subject: Re: pinhole plate tectonics/physics question

Hi Treena

Just this last weekend I saw a geologist making a precise GPS measurement
of the location of a summit in the White Mountains of California. Good to a
few millimeters probably. They make the measurements every year (and in
some places with permanent monuments sevral times an hour to watch the
plate move. several stations let you watch the plate rotate and compress.

In the old days they used surveying tools to measure the locations of the
plates.

You can also use radiotelescopes to measure plate motions. One radio
telescope on the North American plate combines its data with a telescope in
the netherlands or Australia, and by looking for interference fringes in
the radio signal they measure the motion of the plate directly. Plates move
at about the rate that your fingernails grow from 2 to 20 cm a year.

Paul D

>I am wondering what realtionships I can draw between physics and the movement
>of earth's
>paltes - for every action, equal and opposite reaction - okay, but what other
>connections can I
>draw? I am also interested in how plate movement is measured - specifically,
>what is the point
>of reference for making such estimates of the rate of movement of the plates?
>find a point with
>an identifying mark and essentially GPS it? Seems silly to ask, but I would
>like to answer from a
>position of knowledge - teaching summer school this summer
>
>Also, there is the CD/balloon air racer thing - I will be doing that and I
>don't want to miss any
>concepts - decreased resistance with the air, friction decreases as the
>outside force acting to
>stop the glide - this is not my strong suit - so, I put my ignorance out there
>for all to see - any
>help appreciated
>
>thanks
>
>
>Treena Joiful
>
>
>____________________________________________________________________
>
>
>
>---------------------------------------------------------------------------
>To unsubscribe from pinhole, send an email to requests@exploratorium.edu
>with the words 'unsubscribe pinhole' (without the quotes) in the SUBJECT
>of the email.
>
>To subscribe to the digest and only get 1 combined message a day, send an
>email to requests@exploratorium.edu with the words 'subscribe digest
>pinhole' (without the quotes) in the SUBJECT of the email.
>
>Check out what your colleagues have written on Pinhole in the Pinhole
>archives at: http://saturn.exploratorium.edu/ti/alumni/pinhole.html
>---------------------------------------------------------------------------

Date view Thread view Subject view Author view Attachment view

This archive was generated by hypermail 2.1.3 : Mon Aug 02 2004 - 12:05:38 PDT