PSN-L Email List Message

Subject: Re: Passing solar flare geomagnetic shock wave?
From: meredith lamb mlamb1@..........
Date: Sun, 11 Jun 2000 11:31:36 -0700

CapAAVSO@....... wrote:

> Hi Meredith,
>     Thanks for the explanation of how your diamagnetic horizontal seismograph
> works and for updating your website with the solar wind-speed recording. The
> sudden jump in wind speed and the big spike on the Boulder magnetogram both
> coincide with the big spike on your seismogram. Your seismograph is a pretty
> good magnetometer with sensitivity comparable to the Geological Survey flux
> gate magnetometer in Boulder provided the change in the Earth's magnetic
> field is SUDDEN. This is confirmed by the signature of the bus passing by. It
> is a big hunk of iron that swings the magnetically levitated pendulum putting
> a big spike on the trace but quickly returns to its normal position due to
> damping I assume you provided for it as a seismograph. How far is this
> pendulum from the street where the bus passes by?

About 70-80 foot, to the street curb.

> I see what looks like many
> small spikes, mostly pointing downward, that are probably cars passing by.

Yes, the cars also deflect the mass, but nothing like the larger
iron/steel bus's and vans.  Cars usually don't do much noteworthy in any 
amplitude scale.  I use copper plates, or close in eddy current damping,
which is alittle too much for its normal planned seismic use.

> You could check this by watching out the window to see if a big van puts a
> spike on your trace.
> Have fun,
> Cap

Although it won't happen here, I really wonder what the results would be
if this device were situated out in the country, away from the local
magnetic noise (vehicles)?  Of course it would be a scramble of both
magnetic and seismic signals.  With enough shielding, then it may
show somewhat more seismic signals, both here or in the country.

Another source of noise is electric motors, I've noticed some time
back, that it horizontally oscillated (with proper alignment), to a
refrigerator motor some 4 foot away.  Electromagnetic.

Have to confess my ignorance....what does the AAVSO stand
for in your email address?  Your full name?  Any web site? 
Curiosity of course.

Take care, Meredith Lamb


Public Seismic Network Mailing List (PSN-L)

[ Top ] [ Back ] [ Home Page ]

Larry Cochrane <cochrane@..............>