PSN-L Email List Message

Subject: Re: "S" Shear waves ETC...
From: chrisatupw@.......
Date: Sun, 1 Jul 2012 10:46:02 -0400 (EDT)






From: Geoff GM gmvoeth@.........
Sent: Sat, 30 Jun 2012 0:59
Subject: "S" Shear waves ETC...

****I'd like to hear from you guys why some quakes will show no Shear waves=
.
.

Hi Geoff,=20
    An earthquake is the result of rocks slipping deep under=20
ground. I you happen to view the quake 'end on' there will be a low=20
S signal, but a high P signal and the reverse case roughly at right=20
angles - see the beach ball diagrams.

****1. Will shear waves pass through the Mantel ?
.
    Yes.
.
  ****(Mantel is partially liquified ?)
.
    The mantle is solid. The outer core is liquid and shear waves=20
will NOT pass through it. The inner core is solid.
.
****2. Does the solid core spin faster by one rotation in four hundred year=
s ?

(I heard this a long time ago but not sure its for real ?)
.
    If my memory is correct, there is a difference, but I don't=20
remember any details.
.

****3. I wound a coil out of like AWG30 copper wire
It had a Resistance of 86 ohms and it seems to have
a generator constant of about (0.242V/(IN/sec))
Does that sound realistic for a not-so-carefully
wound coil (Wound like a bobbin of thread).

    This wire is too thick to be useful and limits the number=20
of turns that you can put on your coil.
.
****I used 4 rare earth magnets to determine the constant
with about 1 inch of gap where the coil was located.
.
    This gap is much too large. You need to wind thin rectangular=20
coils for good results. Check the left hand sensor coil shown on=20
http://jclahr.com/science/psn/chapman/lehman/index.html=20
and you DON'T give the sizes of the measuring magnets OR the coil!=20
.
****I figure by this it would be best to pay a pro to wind a proper 1K coil=
=20
out of AWG30 wire or a 10K coil out of 40AWG copper wire ?
With this "G" constant I need a gain of about X11
over what I currently am using built be the pros.=20
.
    The way you get high outputs is to increase the magnetic field.=20
Keep the coil resistance below ~500 Ohms for minimum input noise. 10=20
K Ohms is FAR, FAR TOO HIGH.
.

****4. Is it possible to develop a standard amateur Velocity
sensor which we might all get together somehow and have wound
by a pro ? (Its just a coil, but must be well wound)
Like maybe the two options I just specified of AWG30 at 1kohm
  and AWG40 at 10Kohm I know the makers want a terribly expensive
setup fee. Someone like Larry might keep them for future amateurs
who want to build their own sensor stuff ??
That's about 9400feet of wire in whatever gauge (AWG) for a single=20
copper coil. The two coils to be together in a single package ?
.
    You DON'T need to have this done professionally. You just need=20
to find a willing someone with a coil winder.
.
****The solenoids have a too small center opening (id) it probably should b=
e=20
an inch or so inside diameter possibly an inch thick coil.
something easily handled. Then, how to get a G of at least 2.54V/(in/sec).
=20
.
    You need a square coil for a vertical seismometer and a=20
rectangular one for a horizontal seismometer, where boom drift can=20
be a problem.=20
    Why do you want this sensitivity?
 =20
.
****5. Do most seismic waves arrive from below or the sides , and
     can you tell direction by time delay between two stations or more ?
     Not by drawing lines on a map ? Not by N/S E/W knowledge of motions.=
=20
.
    Seismic signals tend to arrive from the side, unless the quake=20
is directly underneath you, or on the opposite side of the world.=20
There is a 'shadow zone' for quakes over about 103 degrees.
    You need three stations for time measurements. Two calibrated=20
horizontal seismometers will give you the arrival direction with=20
an uncertainty of 180 degrees.
..=20
=20
****6. is it possible to build an omnidirectional sensor
    instead of three directionals' to see the motion.

    Not practicable for amateurs.
.
    I strongly suggest that you go to psn.quake.net and download the=20
Quake Analysis Training Manual.
.
    Regards,=20
.
    Chris Chapman



=20

From: Geoff GM gmvoeth@.........<= br> Sent: Sat, 30 Jun 2012 0:59
Subject: "S" Shear waves ETC...
****I'd like to hear from you guys why some qua=
kes will show no Shear waves.
.

Hi Geoff, 
    An earthquake is the result of rocks slipping dee=
p under 
ground. I you happen to view the quake 'end on' there will be a=
 low 
=
S signal, but a high P signal and the reverse case roughly at right =
angles - see=
 the beach ball diagrams.
<=
tt>=

****1. Will shear waves pass <=
font size=3D"2">through the Mantel ?
.
    Yes.
.
  ****(Mantel =
is partially liquified ?)
.
    The mantle is solid. The outer core is liquid and shear wa=
ves 
w=
ill NOT pass through it. The inner core is=
 solid.
.
****2. Does the solid core spin faster b=
y one rotation in four hundred=
 years ?

(I heard this a long time ago =
but not su=
re its for real ?)
.
    If my memory is correct, there is a difference, but I don'=
t 
rem=
ember any details.
.

****3. I wound a coil out of like AWG30 copper wire
It had a Resistance of 86 ohms and it seems to have
a generator constant of about (0.242V/(IN/sec))
Does that sound realistic for a not-so-carefully
wound coil (Wound like a bobbin of thread).
    This wire is too thick to be useful and limits the number <=
/font>
of turns that you can put on your coil.
.
****I used 4 rare earth magnets to determine the constant
with about 1 inch of gap where the coil was located.
..
    =
This gap is much too large. You need to wind thin rectangular <=
/pre>
coils for good res=
ults. Check the left hand sensor coil shown on 
http://jclahr.com/science/psn/chapman/le=
hman/index.html 
and you DON'T give the sizes of the =
measuring magnets OR the coil! 
.
****I figure by this it would be best to pay a pro to=
 wind a proper 1K coil 
out of AWG30 wire or a 10K coil out of 40AWG copper wire =
?
With this "G" constant I need a gain of about X11
over what I currently am using built be the pros. 
.
    The way you =
get high outputs is to increase the magnetic field. 
Keep=
 the coil resistance below ~500 Ohms for minimum input noise. 10 
K Ohms is FAR, FAR TOO HIGH.
.

****4. Is it possible to develop a standard amateur Velocity
sensor which we might all get together somehow and have wound
by a pro ? (Its just a coil, but must be well wound)
Like maybe the two options I just specified of AWG30 at 1kohm
  and AWG40 at 10Kohm I know the makers want a terribly expensive
setup fee. Someone like Larry might keep them for future amateurs
who want to build their own sensor stuff ??
That's about 9400feet of wire in whatever gauge (AWG) for a single=20
copper coil. The two coils to be together in a single package ?
..
    You DON'T need to have this done professionally. You just =
need 
to find a willing someone with a coil winder.
..
****=
The solenoids have a too small center opening (id) it probably should be=20
an inch or so inside diameter possibly an inch thick coil.
something easily handled. Then, how to get a G of at least 2.54V/(in/sec).
 
.
    You need a square coil for a vertical seismometer and a 
rectangular one for a horizontal seismometer, where boom drift=
 can 
be a problem. 
    Why do you w=
ant this sensitivity?
  
.
****5. =
Do most seismic waves arrive from below or the sides , and
     can you tell direction by time delay between two stations or more ?
     Not by drawing lines on a map ? Not by N/S E/W knowledge of motions. <=
/font>
.
    Seismic signals tend to arrive from the side, unless the =
quake 
is directly underneath you, or on the opposite side of the world. <=
/tt>
There is a 's=
hadow zone' for quakes over about 103 degrees.
    You need thr=
ee stations for time measurements. Two calibrated 
=
horizo=
ntal seismometers =
will give you the arrival direction with 
an uncertainty =
of 180 degrees.
=
. 
=20
****6. is it possible to build an omnidirectional sensor
    instead of three directionals' to see the motion.

    Not practicable for amateurs.
=
.
I strongly suggest that= you go to psn.quake.net and download the
Quake Analysis Training Manual.=
.
    Regards, 
.=
    Chris Ch=
apman

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