Single pendulum vs triple pendulum in earthquakes

[kconley]

I am having trouble designing and building a single pendulum and triple pendulum for my experiment. I am trying to see which is better during an earthquake. Thanks.

[barretttomlinson]

Hi,

Here are a couple of sources on the theory and practice of seismographs:

http://www.fedoa.unina.it/1511/01/Ricci ... ismico.pdf

http://jclahr.com/science/psn/wielandt/NMSOP_06.doc

http://pubs.usgs.gov/gip/2006/21/

http://jclahr.com/science/earth_science/

http://geology.com/teacher/earthquake.shtml

http://www.jclahr.com/science/

The first two sites are fairly high level descriptions of seismographs; the lower 5 sites are more general information on earthquakes and seismology for K-12 students.

I hope you find this useful.

Best wishes,

Barrett Tomlinson

[Craig_Bridge]

Youv'e certainly chosen an interesting and challenging area to investigate.

I am having trouble designing and building a single pendulum and triple pendulum for my experiment.

Is there any particular aspect of the design (Isolation, calibration, means of measuring/recording results, something else) that is troubling you or is it just not knowing where to start?

I am trying to see which is better during an earthquake.

I don't think there is much scientific merit in comparing data obtained by a single axis seismograph with that from three identical orthogonal single axis seismographs. The usefulness of the data you get from a single axis device will depend significantly on its axis orientation with respect to the seismological event origin and the type of ground waves generated, something beyond your control in the real world. The three orthogonal axis device(s) will always get you interesting and useful data assuming the wave frequencies are within the usable range of your devices. If I've misinterpreted what you intend to compare and you were actually intending to compare the behavior of a device with a single mass that is unconstrained in three translation axis with the behavior of three masses that are each constrained to a single translation axis which are orthogonal, then you would be comparing two different technologies and your ability to refine each of them in a short project. People have spent years working on improving seismographs and I doubt you will have enough time to master the fine points to make a meaningful comparison.

I'm sure you can come up with a hypothesis that involves seismographs that is useful. You probably need to think a bit on how to make it something that is easily measurable. If your project involves building a seismograph, you also need to think about how you are going to test/calibrate it. You can't count on a significant seismological event occuring at a time that you are recording data unless you are generating a simulated event in your test proceedure.

[kconley]

Thank you so much for your time and those resources.