I should probably know =96 but I don't. What is the "caustic" distance? =
And
for that matter, what is the "caustic"?
Regards,
-Tim-
=20
Timothy Carpenter, P.E., Pres.,
GeoDynamics Consultants, Inc.
5043 Whitlow Ct.
Commerce Twp., Mi 48382
248-363-4529 (voice & fax)
248-766-1629 (cell)
geodynamics@........... (primary)
geodynamics@....... (secondary)
=20
=20
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... =
On
Behalf Of Connie and Jim Lehman
Sent: Sunday, January 09, 2005 7:03 PM
To: psn-l@..............
Subject: Iris Waveform Chart
=20
PSN--thanks for the Iris Waveform Chart for the 9.0 Sumatra 12/26/04 =
event.
The surface wave arrivals of multiple stations exhibited by distance, =
and
text, makes a super graphic. I was wondering about the occurrence of =
a
seismic caustic at the appropriate degree distance. Was the gap at 160
degree area due to no reporting station near the "caustic" distance. In
periodic recording here we've copied three caustics in 20 years--I =
believe
the events were southwest of Australia for us--not a very hot spot.
The 18 sec long period system at James Madison Un. (Virginia) =
working
into a graphic readout read the 8.1 Macquarie Is. event-(l2/23) nicely, =
but
the 9.0 event read 20 min after P-diff arrived and then went off scale =
for
100 minutes and returned to normal recording for the 7.1 event at 04:21.
One can conclude, surface wave arrivals for us (at approx. 145 degrees) =
were
obscured. Keep up the good work.
Jim Lehman
I should probably know – but =
I
don't. What is the "caustic" distance? And for that matter, =
what is
the "caustic"?
Regards,
-Tim-
Timothy =
Carpenter, P.E., Pres.,
GeoDynamics Consultants, Inc.
5043 Whitlow Ct.
Commerce Twp., Mi 48382
248-363-4529 (voice & fax)
248-766-1629 (cell)
geodynamics@........... =
(primary)
geodynamics@....... =
(secondary)
-----Original =
Message-----
From: =
psn-l-request@..............
[mailto:psn-l-request@............... On
Behalf Of Connie and Jim Lehman
Sent: Sunday, January 09, =
2005
7:03 PM
To: =
psn-l@..............
Subject: Iris Waveform =
Chart
PSN--thanks for the Iris =
Waveform
Chart for the 9.0 Sumatra 12/26/04 event. The surface wave =
arrivals
of multiple stations exhibited by distance, and text, makes a =
super
graphic. I was wondering about the occurrence of a seismic =
caustic
at the appropriate degree distance. Was the gap at 160 degree area =
due to
no reporting station near the "caustic" distance. In =
periodic
recording here we've copied three caustics in 20 years--I believe =
the
events were southwest of Australia for us--not a very hot =
spot.
The 18 =
sec long
period system at James Madison Un. (Virginia) working into a =
graphic
readout read the 8.1 Macquarie Is. event-(l2/23) nicely, but the 9.0 =
event read
20 min after P-diff arrived and then went off scale for 100 minutes and
returned to normal recording for the 7.1 event at 04:21. =
One can
conclude, surface wave arrivals for us (at approx. 145 =
degrees) were
obscured. Keep up the good work.
&nbs=
p;
Jim Lehman