On 12/16/2012 2:48 PM, Barry Lotz wrote:
> The waves have different travel speeds.
> Regards
> Barry
> www.seismicvault.com 
>
>
>
> ------------------------------------------------------------------------
> *From:* Bob Hancock 
> *To:* psnlist@..............
> *Sent:* Sat, December 15, 2012 1:46:11 PM
> *Subject:* Re: Missing clear S wave from local event
>
> When an event occurs, there are four basic waves that are generated, 
> the P, S, Love & Rayleigh waves.  The other waves are byproducts of 
> reflection and refraction, but the four basic waves are generated at 
> the event.  However, these four waves take time to properly form and 
> be recognizable.  In addition, your receiver must have sufficient 
> broad band capability to cover the frequencies of the various waves. 
>  The P wave is normally the shorted frequency, followed by the S, Love 
> and Rayleigh waves.  Your receiver is a higher frequency device and 
> you may not be able to see smaller amplitude waves of lower frequency 
> as clearly as the higher frequency receivers.
>
> When the event recorded from the IDA station was expanded to 10 
> seconds, there was one wave that began about 11:12.294, and ended 
> about  11:12.672 that is definitely a lower frequency and may be an S 
> wave.  It would take more work to define that wave as an S wave but 
> there is a possibility for that one.  It appears that the primary 
> problem you are dealing with is the closeness of the station to the 
> event and lack of time for the various waves to be individually 
> distinguishable.
>
> There may be other answers that are more correct, but that is what it 
> appears after expanding the file and looking at it.
>
> Bob Hancock
>
>
>
> On Dec 15, 2012, at 9:32 AM, Tiago A.  > wrote:
>
>> Hi.
>>
>> Sorry for the late reply.
>>
>> The sensor is a L4 1Hz, i do have a noisy system due to several 
>> factors (some already discussed here in PSN Listing Mail).
>>
>> Here is the SAC file of the event:
>> http://dl.dropbox.com/u/15802004/12_10_2012.sac
>>
>> This the SAC file of the IDA station located +-10km of the event 
>> (much better recording than mine).
>> http://dl.dropbox.com/u/15802004/cmla_12_10_2012.sac
>>
>> I do not know if this is a "natural" event, while i do receive some 
>> "blasts" every month, at 4am i dont believe to be a blast.This event 
>> is located near a dormat volcano, that 10 years back had high seismic 
>> crisis. Some believe that the geothermal exploration on that system 
>> turned the system a bit unstable ( coincidence when they started the 
>> exploration back in the 80s, the area had a big seismic crisis). This 
>> event was classified with Ml1.8, 5km depth.
>>
>> So the hypothesis are:
>> -Only S wave was recorded, P wave is missed between the noise.
>> -Only P wave is clearly recorded.
>> -Due to short distance to the epicenter, P and S waves are mixed 
>> together.
>>
>> But except this event and 1/2 more, i can always understand if a P is 
>> recorded or not. Comparing my SAC file with the CMLA IDA station, 
>> what do you think?
>>
>> Best Regards,
>> Tiago.
>>
>>
>
Did anyone mention that S waves dont travel throgh liquids like lava 
chambers
or Liquid Outer Cores ? They can chang from P to S and back again but loose
energy at each and every velocity boundary.


  
    
  
  
    
On 12/16/2012 2:48 PM, Barry Lotz
      wrote:

    
    

      
      
The waves have different travel
        speeds.

        
 
        Regards

        Barry

        www.seismicvault.com

          

        
        


        
        


          

              
From:
              Bob Hancock <raptor@.......>

              To:
              psnlist@..............

              Sent: Sat,
              December 15, 2012 1:46:11 PM

              Subject:
              Re: Missing clear S wave from local event

            

            
When an event occurs, there are four basic waves that
              are generated, the P, S, Love & Rayleigh waves.  The
              other waves are byproducts of reflection and refraction,
              but the four basic waves are generated at the event.  
               However, these four waves take time to properly form and
              be recognizable.  In addition, your receiver must have
              sufficient broad band capability to cover the frequencies
              of the various waves.  The P wave is normally the shorted
              frequency, followed by the S, Love and Rayleigh waves.
               Your receiver is a higher frequency device and you may
              not be able to see smaller amplitude waves of lower
              frequency as clearly as the higher frequency receivers.
            


            
            
When the event recorded from the IDA station was
              expanded to 10 seconds, there was one wave that began
              about 11:12.294, and ended about  11:12.672 that is
              definitely a lower frequency and may be an S wave.  It
              would take more work to define that wave as an S wave but
              there is a possibility for that one.  It appears that the
              primary problem you are dealing with is the closeness of
              the station to the event and lack of time for the various
              waves to be individually distinguishable.
            


            
            
There may be other answers that are more correct, but
              that is what it appears after expanding the file and
              looking at it.
            


            
            
Bob Hancock
            


            
            


            
            


            
            
On Dec 15, 2012, at 9:32 AM, Tiago A. <tiagoagre@.........>
              wrote:
            


              
Hi.

                

                Sorry for the late reply.

                

                The sensor is a L4 1Hz, i do have a noisy system due to
                several factors (some already discussed here in PSN
                Listing Mail).

                

                Here is the SAC file of the event:

                http://dl.dropbox.com/u/15802004/12_10_2012.sac

                

                This the SAC file of the IDA station located +-10km of
                the event (much better recording than mine).

                http://dl.dropbox.com/u/15802004/cmla_12_10_2012.sac

                

                I do not know if this is a "natural" event, while i do
                receive some "blasts" every month, at 4am i dont believe
                to be a blast.This event is located near a dormat
                volcano, that 10 years back had high seismic crisis.
                Some believe that the geothermal exploration on that
                system turned the system a bit unstable ( coincidence
                when they started the exploration back in the 80s, the
                area had a big seismic crisis). This event was
                classified with Ml1.8, 5km depth.

                

                So the hypothesis are:

                -Only S wave was recorded, P wave is missed between the
                noise.

                -Only P wave is clearly recorded.

                -Due to short distance to the epicenter, P and S waves
                are mixed together.

                

                But except this event and 1/2 more, i can always
                understand if a P is recorded or not. Comparing my SAC
                file with the CMLA IDA station, what do you think?

                

                Best Regards,

                Tiago.

                

                

              
            
            

          
        
      
    
    Did anyone mention that S waves dont travel throgh liquids like lava
    chambers

    or Liquid Outer Cores ? They can chang from P to S and back again
    but loose

    energy at each and every velocity boundary.