PSN-L Email List Message

Subject: Re: And Now A Simple Question
From: Stephen & Kathy skmort@............
Date: Thu, 31 Dec 2009 22:56:47 -0800


FYI, (sorry if this was already
mentioned), the USGS Earthquake time travel calculator uses the IASP91
model, as per the note at the bottom of the page; see the following

The USGS "Theoretical P-Wave Travel Times" map with shadow zones, also says it uses the IASP91 model.  Following is a link to an example for the 6.0 Banda Sea quake on Dec 26...  see notes below map.

  PSN Station #55

GPayton wrote:
Thanks to you, Larry and all that answered.  I've searched and can only find that the IASP91 is the newer, but cannot discover that it would matter that much in my limited sensor setup and environment.  Looking at other posts, the JB seem to be the favorite, if not be default.
Regards & Happy new Year to All
----- Original Message -----
From: Larry Cochrane
To: psn-l@..............
Sent: Thursday, December 31, 2009 2:46 PM
Subject: Re: And Now A Simple Question

Hi Jerry,

The JB and IASP91 tables are different travel time models of the earth. I think the
IASP91 table is newer so it might be more accurate.

Larry Cochrane
Redwood City, PSN

GPayton wrote:
> After the recent "high level" discussions, I would like to present one at MY
> intelligence level. (NO puns, please)
> Please tell me the significant differences in using the JB vs. the IASP91
> tables?
> Given a chosen event, switching between tables will result in different
> times, distances and etc.  How do I know WHICH to use in WinQuake.
> Thanks,
> Jerry

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