PSN-L Email List Message

Subject: Re: P & S Markers Location, WQ
From: "Larry Cochrane" lcochrane@..............
Date: Sun, 2 Jan 2005 20:09:26 -0800

Happy New Year Everyone,

Hi Steve,

You won't see a P or S wave after ~11000 km. This is because the earths core
creates a shadow of the P wave and the outer core a shadow of the S wave. If
you do a google search you can find more information. This page as a nice
image showing what going on with the P and S waves. The IAPS91 travel-time
table has information that goes past 11000km so WinQuake will place the P
and S marks in the window, but they are meaningless do to the shadowing

Larry Cochrane
Redwood City, PSN

----- Original Message ----- 
From: "Steve Jones" 
Sent: Sunday, January 02, 2005 5:39 PM
Subject: P & S Markers Location, WQ

> Hi Larry,
> I have a question re: Winquake, and the P&S Marker location.  I recorded
> 12/26/04 M9.0 event (along with everybody else) and the later 01/01/05
> event off Sumatra.  On both of these, I cannot get the P & S marker
> locations on the record to align with the first arrival of the P and S
> at my location.  For each event, Winquake does calculate the distance to
> location from the epicenter at 15000+ Km.
> I am running the WQ version 2.9, if that info helps.  I have very
> checked my timing and event location data plugged into Winquake.  Do you
> have any idea why the P & S calculation seems to be off?
> If need be, I can email the two event records to you for your examination.
> Thanks,
> Steve Jones
> Huntsville, Alabama
> __________________________________________________________
> Public Seismic Network Mailing List (PSN-L)
> To leave this list email PSN-L-REQUEST@.............. with
> the body of the message (first line only): unsubscribe
> See for more information.


Public Seismic Network Mailing List (PSN-L)

[ Top ] [ Back ] [ Home Page ]