Thanks to Jim & Connie for thier post- I have always enjoyed them over t=
he years!
Comments on Recording P & S: =

Explosions do not generate very large S waves – mostly P. Generall=
y speaking the vertical (V) sensor records P better than an S wave. Conv=
ersely, the Horizontal (H) sensor records S better than P. The O&G seism=
ic crews call Vertical phones P wave phones, and Horizontal phones S wav=
e phones. They deal with mostly dynamite and Vibroseis sources (~10-500 =
Hz). Of course, the Vertical & Horizontal phones record both or either (=
P &S), if it is there! =


The UNE’s at NTS would normally release some of the built up rock =
stresses and consequently show a little more S wave than what the explos=
ion generated. One looks for the lack of an S component on the seismic r=
ecord to decide if it may be an UNE rather than an earthquake. Most EQ&r=
squo;s produce both P & S, but look at the H components to see the S bes=
t. Also, look for the large Rayleigh wave on the V, and Love waves on th=
e H.

A method for hiding an UNE would be to shoot it in the middle of a large=
 cavity so very little S wave is generated. I assure you this is very di=
fficult to do when you’re shooting large (KT) shots buried at a de=
pth of a thousand feet which is required for containment.

Jim
Boulder City, NV

---------- Original Message ----------
From: "Jim and Connie Lehman" 
To: 
Subject: Lack of Shear--
Date: Thu, 13 Dec 2012 17:22:01 -0500


PSN Friend=
s--In reference to seismic readouts lacking "S" waves, I was reminded of=
 the early records years ago of underground atomic tests--Nevada.  We we=
re told the cavity formed deep underground was spherical in shape result=
ing in a point source detonation--and no "S" shear appeared on records c=
opied here in Virginia.    I guess it would be possible to have a natura=
l event exhibiting a point source, but our understanding of what trigger=
s earthquakes would make that unlikely.  Perhaps your location in refere=
nce to the direction of underground displacement may affect the amplitud=
e of "S"......   Seasons Greetings to All    Jim Lehman
____________________________________________________________
Woman is 53 But Looks 25
Mom reveals 1 simple wrinkle trick that has angered doctors...
Thanks to Jim & Connie for thier post- I have always enj=
oyed them over the years!
Comments on Recording P & S: <=
br>Explosions do not generate very large S waves – mostly P. Gener=
ally speaking the vertical (V) sensor records P better than an S wave. C=
onversely, the Horizontal (H) sensor records S better than P. The O&=
G seismic crews call Vertical phones P wave phones, and Horizontal phone=
s S wave phones. They deal with mostly dynamite and Vibroseis sources (~=
10-500 Hz). Of course, the Vertical & Horizontal phones reco=
rd both or either (P &S), if it is there! 

The UNE&r=
squo;s at NTS would normally release some of the built up rock stresses =
and consequently show a little more S wave than what the explosion gener=
ated. One looks for the lack=
 of an S component on the seismic record to decide if it may be an UNE r=
ather than an earthquake. Most EQ’s produce both P & S, but look at the H component=
s to see the S best. Also, look for the large Rayleigh wave on the V, an=
d Love waves on the H.

A method for hiding an UNE would be=
 to shoot it in the middle of a large cavity so very little S wave is ge=
nerated. I assure you this is very difficult to do when you’re sho=
oting large (KT) shots buried at a depth of a thousand feet which is req=
uired for containment.

Jim
Boulder City, NV

----=
------ Original Message ----------
From: "Jim and Connie Lehman" <=
lehmanjc@...........>
To: <psnlist@..............>
Subjec=
t: Lack of Shear--
Date: Thu, 13 Dec 2012 17:22:01 -0500

<=
!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
PSN Friends--In referenc=
e to seismic readouts lacking "S" waves, I was reminded of the early rec=
ords years ago of underground atomic tests--Nevada.  We were told t=
he cavity formed deep underground was spherical in shape result=
ing in a point source detonation--and no "S" shear appeared on =
records copied here in Virginia.
    I guess it would be p=
ossible to have a natural event exhibiting a point source, but our under=
standing of what triggers earthquakes would make that unlikely.&nbs=
p; Perhaps your location in reference to the direction of underground&nb=
sp;displacement may affect the amplitude of "S"...... 
=
  Season=
s Greetings to All    Jim Lehman



_____________________________=
_______________________________
Woman is 53 But Looks 25
Mom reveals 1 simple wrinkle trick that has angered doc=
tors...
Consum=