Potential uses of these data

1. In a paper we plan to submit for publication roughly simultaneously with this report, Poppeliers and Pavlis [2001] used data primarily from array 3 to study topographic site effects.  We found that topographic site effects seem to be one of those favored topics for people working on computer simulation of wave propagation, but there is almost no useful data on the subject.  Every study we could find on topographic site effects used station spacing far too wide to do any type of wavefield processing and results were limited to relatively crude amplitude measurements.  Array 3 provides some stunning results on topographic wave propagation effects.  Until the paper is published look for a preprint under our anonymous ftp site .
2. These data have some very interesting applications to explosion source physics, particularly underwater explosives and seismic coupling questions.  Anyone interested in this subject is encouraged to print out and read the unpublished report I wrote for the Navy (Pavlis, 1999) that is stored with these data.  The report describes the spectral technique I used to isolate the source and propagation terms and average the results.  The basic idea is that because we have a source whose location is essentially fixed relative to the profile stations spectral ratios between shots provided information on relative source spectral characteristics from shot to shot.  The most remarkable result, I think, is found in  Figure 3.   That result shows that the high frequency output of these explosions is essentially independent of shot size.  The primary variation in spectral amplitude is at frequencies below about 20 Hz.  The literature on underwater explosions is enormous and perhaps this is a well known phenomenon, but I find it surprising.  A working hypothesis is that it represents the fact that no material can maintain a shock front below a minimum scale length without being totally disrupted.  In nuclear explosion physics this is the concept of a transient cavity within which all the material inside the cavity is first vaporized then permanently deformed.  The effective source is a volume is related to when the expanding stress field around this cavity drops to near the elastic limit.  At that critical size the source begins to radiate elastic waves at a characteristic period.   In the case of water, this probably means that the initial transient bubble formed by the explosive gases initially has enough energy to vaporize water causing a critical shock front limit.  This is different from the nuclear case because the explosive detonation time constant is much longer and there may be radiation effects that spread the pulse as the water bubble expands.  That is, the pulse rise time is what presumably controls the high frequencies in the data, and the observations in figure 3 indicate some physical process that puts an upper limit on the pulse rise time.   The point is that these data provide some potentially useful data to test theoretical models of seismic sources, particularly underwater explosions.
3. I mentioned earlier that these data have some very interesting potential for measuring wave propagation effects and particularly the scattering characteristics of surface waves.  The mining spoil/bedrock interface is about as dramatic a real interface as could be conceived.  It is unique it than it is an absolutely flat surface (Mining stopped at the base of the lowest coal unit the mining company was after -- they do not move extra rock for any reason as it costs them a lot of money to do so.)  covered by a totally homogenous material (Fractured sandstone and shale fragment with scale lengths from about 1 m downward in size mixed up as if they had been run through a blender.).  The Pennsylvanian rocks below the mined area are rather complex fluvial deposits at the outcrop scale, but at seismic wavelengths they are relatively homogeneous.  In short, this is a pretty unique experimental measurement for wave propagation studies as it is not complicated greatly by potential anisotropic effects.  It is complicated strongly by strong variations in the thickness of the near-surface waveguide formed by the mining spoil.  There are several 10s of meters of topography across the site.  I apologize that I am unable to supply a topographic map of the area as I do not have one.  A more dramatic features is that the waveguide abruptly terminates at the lake shore and at the boundaries of the mined area.  As a result, there is strong observational evidence in these data that surface waves are strongly reflected from these essentially vertical discontinuities in the near-surface waveguide.  The combination of the linear profiles with arrays 1 and 2 (I actually designed these arrays with this problem in mind.) make this a powerful tool to understand how surface wave interact with vertical boundaries.  I'd love to work on this problem some day, but I don't see a window of time to do so for several years so have at it.  I wish you luck.
4. In addition to source physics, a more complete study could be conducted on how different parts of the wavefield depend upon source depth.  My report to the Navy used only simple spectral techniques because I used these as a way to better quantify an empirical size/depth relation for them.  A more comprehensive study could be conducted to measure quantities like the relative excitation of surface waves, P, and what I called Pd in the  data section.   This could provide useful high-precision data to better understand empirical discriminates like Rg to P ratios being experimented with at this time in the nuclear monitoring world.
5. The air wave data interaction with buildings seen in the accelerometer data is amazing and indicates how strong the airwave generated by some of these shots was.  (I note the personal experience of actually being able to feel a pulse of air with some of the large shallow shots, although clearly most of the energy was at frequencies below the limit of my hearing.)  A good student project is to try to model the interaction of the airwave with a building to see if there is any consistency with independent measurements of air pressure made by Navy personnel.  Unfortunately, I do not have the air pressure data available to me, but if I am still around when you read this and you want to pursue this I'll try to connect you with the right people.