PSN-L Email List Message

Subject: RE: Surface waves from Sumatra M 9.0, 2nd Version
From: "Timothy Carpenter" GeoDynamics@.......
Date: Thu, 6 Jan 2005 17:31:04 -0500

You asked a couple of questions after giving us the link to the Global
Displacement Wavefield. I started to write up a quick answer, but since =
new to the group I thought I better find out a bit more about who was =
the questions. I'm glad I did. I'll leave the questions unanswered for
others to ponder. I presume after some reasonable amount of time, you =
provide the answers.=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)

-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... =
Behalf Of twleiper@........
Sent: Thursday, January 06, 2005 2:38 PM
To: psn-l@..............
Subject: Re: Surface waves from Sumatra M 9.0, 2nd Version

I would suspect destructive interference of the wave fronts
at the quarter-wave point (50 minutes) assuming the resonance
of the "global tank circuit" is 200 minutes. Either that or
some type of phase shift. How about the coriolis effect ? :-)

-- John or Jan Lahr  wrote:
If you haven't taken a look at the IRIS "Image of the Week" yet,
check out this page (with the now correct URL!):

The image shows seismic records from stations distributed around
the globe and surface waves that traveled twice around!

Questions to think about --  Why does the y-axis stop at 180 degrees?
Why would the amplitude of the surface waves fall off around 90 degrees
and then increase at 180 degrees again?

Public Seismic Network Mailing List (PSN-L)


Public Seismic Network Mailing List (PSN-L)

[ Top ] [ Back ] [ Home Page ]