[Polynikes]

Strange wave pattern. Look at the green tracing. Almost like an explosion?

http://www.seis.utah.edu/helicorder/icu_webi.htm

[adaven]

Strange wave pattern. Look at the green tracing. Almost like an explosion?

That is strange indeed.

[CARTOUCHE]

Almost like an explosion.

Except for all the aftershocks over several hours. I would negate any idea of an explosion that was man made. However, magma is definitely under the ground there as evidenced by all the hot springs in the region. A sudden movement of magma perhaps?

[Monkey Face]

And we are so close to the Test Site...

[Godzilla]

The green tracing reflects the 15 minute period of the recorder time - allows seismologists to tell one event from another since they spread all over a sheet.