PSN-L Email List Message

Subject: Re: Fiji area quake
From: Mark Robinson mark.robinson@...............
Date: Mon, 10 Dec 2007 15:30:07 +1300

Thomas Dick wrote:
> You're right John, I am NOT close to 180 degree from the epicenter. I 
> have put the data in over ten times. Early on, I even reverse the 177 to 
> a positive number to try and get it to show phases think it was an error 
> on the post. The travel time table shows 107 degrees and 11896 km. I 
> have made mistakes before...particularly before two cups of morning 
> coffee but not this time.

"The shadow zone is the area of the earth from angular distances of 104 to 140 
degrees from a given earthquake that does not receive any direct P waves."

> ----- Original Message ----- From: "John Lahr" 
>> Check that you have the correct lat and lon for the Fiji event.  It 
>> was not 180 degrees away from the mid west.
>> For computed distances, see this USGS page:
>> This page includes two seismograms from Oregon:
>> At 02:03 PM 12/9/2007, you wrote:
>>> I don't think this is so simple. May be a quark in the software in 
>>> reference to the location here in midwest -- too close to 180 
>>> degrees. There is no doubt that I got a good record. The arrival of 
>>> Pdiff appears the same as on the local university helicorder and if I 
>>> try to place Pdiff and S manually, I can get phases to come in (if I 
>>> use the locate feature in conjunction) but if I move S  one way or 
>>> the other just a little everything disappears..I even processed a 2.4 
>>> locally about twenty minutes before with no trouble. So Larry's 
>>> program works fine!
>>> ----- Original Message ----- From: "Mark Robinson" 
>>> To: 
>>> Sent: Sunday, December 09, 2007 3:48 PM
>>> Subject: Re: Fiji area quake
>>>> Thomas Dick wrote:
>>>>> Is there anything wrong with the time or location for the 7.8 quake 
>>>>> today? I'm not able to put the data into Winquake and get phases. I 
>>>>> certaining register the quake in the time frame that it was suppose 
>>>>> to arrive.
>>>> I felt that quake here at almost 1800km distance and can confirm the 
>>>> time.
>>>> Looking at the traces I think it would be difficult to characterise 
>>>> the event as instantaneous.
>>>> I was particularly struck by the huge very long period (~30min) 
>>>> waves shown on the Kermadec LISS seismograph shortly after the event 
>>>> (before they were obliterated by traces from subsequent hours).

Mark Robinson
10 Dec 1953 Winston Churchill wins Nobel prize for literature.
10 Dec 1965 Annie Crummer born.
10 Dec 1972 Split Enz play their debut at Auckland Wynyard Tavern.

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