I have heard "somewhere on the internet" that 5 second period microseismic waves
are generated by waves in the oceans waters at certain resonant depth
and radiate for very long distances.
This has been determined through scientific observations.
Not to say other phenomena do not also create
5 second waves.
I often see such waves relating to weather fronts coming from
the pacific before it hits arizona.
And my system was designed only to see
3 second to 2Hz range so they must be
quite large in magnitude.
Its not weather over land but weather over ocean.
geoff

----- Original Message ----- 
From: "Thomas Dick" 
To: 
Sent: Sunday, November 02, 2008 6:40 PM
Subject: Re: unusual frequency


> May I add to your comments ---
> 1. first, there was a 3.1 in Oklahoma around 10:30 UTC, a 2 in Tenneesee 
> and a whole series of Texas quakes starting around 23 UTC --- these are 
> LISTED on regional networks .... BUT, there could be unlisted minor 
> events BUT shouldn't these events be in the .6 Hz/period of 1.5 for 
> regional events which is higher than what I was seeing
> 
> and what I was questioning....
> 2. "Quiet weather all over U.S. right now. Starting about 18:30 on 10/30 
> I began seeing a large amplitude signal coming in. It peaks at ~.2 Hz or 
> 5 sec period It is twice as strong as the earthquake in Texas (~5 on Oct 
> 31) here in southern Indiana. Is anyone else seeing this?"  
> and probably some form of weather phenonmena???
> 
> 
> Bob Hancock wrote:
>> Without knowing the epicenter of the event, you cannot draw too many 
>> conclusions.  I downloaded the event using VASE, and look at it with 
>> SAC.  I used the unfiltered raw data from the IU/TUC station (STS-1) 
>> and believe the P wave arrival time is 13:36:20 for that station.  I 
>> can pick out the Love & Rayleigh waves.  However, the S wave is of 
>> very low amplitude.  I observed one very low amplitude oscillation 
>> that could correspond to an S wave about 13:37:25, for a S-P time of 
>> 65 seconds or 4.47 degrees ( 496.75 km).  In addition, the rayleigh 
>> waves are much more pronounced on the vertical and north channels 
>> which would be consistent with an event that is more southerly from 
>> the receiving station than southwest.  The Love waves first appear 
>> about 13:37:45, and the Rayleigh waves appear about 13:38:25.  Without 
>> more information, it is not really possible to draw any conclusions on 
>> why there was a diminished S wave.  I have not looked at the event 
>> with other than my station and Tucson.  To me, it looks like a normal 
>> regional event, but with a magnitude of less than 4.0, most likely 
>> south of the border in Mexico.
>>
>> Keep in mind one big problem in analyzing regional events is there is 
>> insufficient time for good wave separation.  They are all together and 
>> that can complicate trying to pick out individual waves.
>>
>> Bob Hancock
>>
>>
>>
>> On Nov 2, 2008, at 2:11 AM, Geoff wrote:
>>
>>> Hello Bob;
>>> me Not being a physics major or math person.
>>> Thats Interesting since I had a s-p or s-L time
>>> of 2 minutes and that translates to
>>> 600 + miles maybe 700. This event set off
>>> my automatic recording which usually does
>>> not happen unless the quake is about 4.0
>>> at 400 miles. For some reason more energy then
>>> expected has arrived at this station sort of like
>>> what bubbleheads ( submarine sailors )
>>> might call a convergence zone
>>> which happens in the ocean with sound waves.
>>> Maybe quake waves in the earth behave like
>>> sound waves in the ocean and are lazy which
>>> will focus the energy at discreet distances
>>> from the event. By lazy I mean they seem
>>> to bend ( refract ) to the slowest velocity hitting the surface
>>> with concentrated focused energy
>>> in concentric rings around the event out to
>>> some distance. Such behavior requires enough
>>> depth of the strata to allow for this bending to happen.
>>> Does this mean possibly deep crust or from the mantel ?
>>> I should imagine the moho would keep a CZ zone
>>> from the crust because it would reflect at that point
>>> and divide the energy instead of refracting it.
>>> What do you think might be going on that
>>> would concentrate the energy from a less than
>>> usual quake to set off my recording alarm ?
>>> I understand wave velocity changes is the best way
>>> to guess how waves are effected as they propagate.
>>> Any sudden change is like a mirror and a gradual
>>> change is like a lens.
>>> I understand a transmitted ( radio wave ) signal can be bent
>>> by having a series of antennas with a phasing
>>> slightly later from antenna to antenna so that
>>> the delaying of the phases of a single wave
>>> will make the antenna behave as a massive
>>> variable lens thus the phased array kind of antenna
>>> or wullenwebber array.
>>> Since we can not do what mother nature has
>>> not already done in one way or another I can
>>> imagine the earth itself is somehow making
>>> areas of more and less energy as energy spreads
>>> away from the focal point. I must have been
>>> in an increased energy point if the quake
>>> was less than 4.0 and 600 miles away.
>>>
>>> Regards;
>>> geoff
>>>
>>>
>>> ----- Original Message ----- From: "Bob Hancock" 
>>> To: 
>>> Sent: Saturday, November 01, 2008 8:16 PM
>>> Subject: Re: unusual frequency
>>>
>>>
>>>> This event appears to be consistent with other low magnitude events  
>>>> that  have occurred to the Southwest of Tucson, AZ.  I have seen 
>>>> other  events that are similar, and no information was ever posted 
>>>> on them.   I noticed the event was visible across the lower 48 
>>>> states, and  southern Alaska.  It is most likely less than M 4.0 as 
>>>> that is the  USGS minimum cutoff for display of information on 
>>>> international events.
>>>> Bob Hancock
>>>> On Nov 1, 2008, at 2:53 PM, Geoff wrote:
>>>>> Hello Mr. Thomas Dick;
>>>>> My Sensor located very close to 33.42138N  -111.57477W about  
>>>>> 507Meters above mean sea level.
>>>>> I saw that TUC near Tucson also saw this signal about 1336 to 1338  
>>>>> on 31OCT2008 UTC.
>>>>> I have not analyzed it to get an accurate and precise time simply  
>>>>> because I can not
>>>>> tell for sure it is in fact an Earthquake. If no one else is  
>>>>> reporting it I do not trust
>>>>> what I am looking at. In order for me to properly read a signal it  
>>>>> takes extra effort
>>>>> which translates to opportunity costs ( such as Battlefield 2142  
>>>>> time ) so I will not
>>>>> pursue more knowledge in detail if I can not verify the source  
>>>>> beforehand.
>>>>> The distance seems 600 miles to 700 miles from here maybe magnitude 4
>>>>> but nothing seems to match that as of my last look.
>>>>> Regards;
>>>>> geoff
>>>>>
>>>>> -
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