Hello All,
    I have been recording with an infrasound detector on loan from the 
Geophysical Dept. of Southern Methodist University for several months now.  The 6.7 
Gulf of California quake is the first event I've been able to correlate with a 
quake.  (see my PSN postings).
    The local infrasound signal recorded here in Dallas was not caused by a 
teleatmospheric pressure wave from the quake, but was generated by the seismic 
surface wave coupling to the atmosphere at my location, causing corresponding 
vertical movements of the infrasound detector diaphram which in turn disturbed 
the local atmosphere.  The infrasound disturbance was initiated at the same 
time as the surface waves arrived, and lasted about 15 minutes, the same 
duration as the surface waves.  There was no indication of a teleatmospheric 
acoustical pressure wave, which would have arrived at my station about 1.3 hours 
after initiation of the quake.
    I found this event very interesing and am passing the info along for your 
possible interest.
    Regards,
    Al Hrubetz
    Dallas, Texas




Hello All,
    I have been recording with an infrasound det=
ector on loan from the Geophysical Dept. of Southern Methodist University fo=
r several months now.  The 6.7 Gulf of California quake is the first ev=
ent I've been able to correlate with a quake.  (see my PSN postings).

    The local infrasound signal recorded here in=
 Dallas was not caused by a teleatmospheric pressure wave from the quake, bu=
t was generated by the seismic surface wave coupling to the atmosphere at my=
 location, causing corresponding vertical movements of the infrasound detect=
or diaphram which in turn disturbed the local atmosphere.  The inf=
rasound disturbance was initiated at the same time as the surface waves arri=
ved, and lasted about 15 minutes, the same duration as the surface waves.&nb=
sp; There was no indication of a teleatmospheric acoustical pressure wave, w=
hich would have arrived at my station about 1.3 hours after initiation of th=
e quake.
    I found this event very interesing and am pa=
ssing the info along for your possible interest.
    Regards,
    Al Hrubetz
    Dallas, Texas