Science Buddies: "Ask an Expert"

I have an idea to propose using magnetic levitation as a way for a building to survive an earthquake. We had an 8.1 EQ here in guam years ago. I ordered a Levitron Revolution (magnetic levitation device) http://fascinations.com/unique-toys-gif ... series.htm and will use this to levitate a balsa wood building model. I want to simulate an earthquake at various magnitudes by shaking the table and seeing how much disruption it can take before falling over. I need to measure the EQ. I can use SeisMac on my laptop but not sure how to convert that to Richter scale. I guess I could order a seismograph but am not sure if it will properly measure my "fake earthquake" of table shaking?

First question: What is the best method to measure a simulated earthquake?
Second question: Any ideas on project elements, additional thoughts or anything I should be thinking about?

My question: Can a magnetic levitating building be used to withstand earthquakes?

In general, Yes. You would be isolating the building from ground motion. Current fuilding technologies are using rubber base plates and slide plates to do this now. Magnetic levitation is just very expensive and requires a power source.

Thank you for your response. I read about base plates and slide plates in my research.

What I'm trying to measure and figure out is "at what point is the magnetic field broken by the movement of the ground below and the building falls". It's a little complicated and hard to measure the three dimensional (and invisible) magnetic influences. For simplicity I am just going to simulate an earthquake and use a seismograph to measure the point at which the levitation fails.

Do you have any suggestions on how I can best SIMULATE an earthquake? I could just shake a table, but from what I read, earthquake patterns are very complex and move in multiple directions at various depths. I'm not sure that by simply shaking the table until the magnetic connection breaks I'm really proving anything about how a real earthquake or real building might react?

Any thoughts are greatly appreciated.

Thank you so much.

Michael

Ignoring your magnetic levitation aspect, you have chosen an extremely complex area of investigation. Earthquake isolation involves dynamics. Dynamics have frequency and magnitude aspects. Buildings have complex harmonic responses and no two buildings are exactly alike. Different earthquakes have different wave dynamics, points of origin, direction of wave propagation, etc. What all this means is that what works for one building is not likely to work for others. What works well for one earthquake might not work well for another (and vice versa).

Now if you add to the complexity by introducing magnetic levitation which is an inheritly unstable state that requires balanced positioning forces (I'll call them centering forces) to maintain the orientation of the levitated mass centered on the levitating force, you have introduced an instability into the mix. If a "shake" event happens that is an exact multiple of a resonant frequency of the levitated mass, the building will oscillate and each wave will move the building further until it overcomes the positioning forces and the levitation force becomes a motive force moving the building still further until the limit of the opposing centering force is exceeded in which case the building goes sliding out of the levitating forces.

Combining an investigation of magnetic levitation with an investigation of earthquake isolation is combining two extremely difficult investigations and isn't likely to be a project that you can come up with a hypothesis that can be answered in the time available for a Science Fair project.

Dear Mr. Bridge, thank you so much for your helpful answer. It has pointed me in a new direction for research and the experiment. thank you