Regarding the 1993 quake, it was just a quake. [To paraphrase Freud, "Sometimes a cigar is just a cigar."] What I was doing is finding the quake
first, then looking up the date on the test list. In the case of the 1993 quake, I didn't notice it was beyond the test ban treaty limit.
I ran the USGS search on all the days mentioned in the Caltech article. I picked Palm Springs as the center point, and searched for 200km. That is far
enough to cover beyond Edwards. Only June 18, 1992 has quakes that show up on the USGS search. The only one that was shallow is shown here:
Google Earth apparently doesn't save the data in the box, but it was a magnitude 2.9 at 8:06:13 UTC, which would be about 6 minutes after midnight
local time. The location is about 9km south of 29 Palms.
You can download the full file with 3 quakes on it here:
Again, you need to save the file on your hard drive then open it with Google Earth.
Three conclusions here. One, the sky quake analysis done by Caltech is using events too weak to show up on the USGS server. The fact the server can
miss a few nuclear explosions is proof enough that using quake data from the internet isn't sufficient for such analysis.
Two, using the Caltech analysis, the seismic disturbances are consistent with a high altitude sonic boom. Technically, this doesn't rule out some
other event created the data. [In logic, there is a difference between "if" and "if and only if", i.e. conditional versus biconditional.]
A third conclusion is if you see the quake on the USGS, it is probably not from a sonic boom. Sonic booms can be detected, but are not strong enough
for the USGS to report. Such chatter has appeared in forums in the past and now appears to be a dead end.
There are viewing events and sonic events. Most likely the person making the report saw or heard something. But you can't draw much from eyewitness
or "earwitness" testimony, especially if they aren't an expert witness. Rather the only use for such reports is they give a time frame to start the
In a DSP class in college, we were given signals to analyze. Running the signals through various types of analysis, only one seems to contain
something, while the others were noise. The assignment was intentionally tricky in that we were fed random noise to show that we could recognize
random noise. Now how does this relate to the Caltech study? Well one they had their analysis program working, they should have run it through days
when there were no detected sky quakes. If the analysis program detects nothing, that is also useful information. That is, the scheme is not prone to