Mystery Sonic Boom in Phoenix

From: campbell@ufomind.com (Glenn Campbell, Las Vegas)
Date: Mon, 3 Mar 1997 19:29:43 -0800
Subject: Mystery Sonic Boom in Phoenix

From: [Withheld by request]
Date: Mon, 3 Mar 1997 10:02:00
Subject: Mystery Sonic Boom
To: campbell@ufomind.com

Just a tidbit that might support the strange contrail sighting commented on
the mailing list. On friday (2/28/1997) at about 1:40 PM we had a very
sharp sonic boom in my area (north Phoenix.) I was working at home and
called in to the office, and it was heard there (about 20 miles south), and
my wife's parents also heard it (20 miles east.) There were no news reports
on TV or in the newspaper about this (previously, when Motorola rented a
SR-71 and made some booms here, there were.)

What I though was really interesting is that I had read that sonic booms
registered on seismographs, so I though I'd do a web search and see if the
data was on line to see what a boom looks like. A link from a link on the
UFOMIND site brought me to the IRIS DMC (http://www.iris.washington.edu/).
One can indeed check seismic data there (no sonic booms registered in the
area at the time). But I thought is was fascinating that partial funding
for the data management center comes from the Air Force Office of
Scientific Research! Also, the site refers to forms to fill out to get
access to "restricted data sets." Top secret earthquake data?

Have any idea how to spot/find seismic data on sonic booms?