- Example use of bplt to generate Post Script plot of down-hole
data.
Traces are plotted by geophone elevation. Data from a Boise River gravel
borehole, B5.
- Example use of bplt to focus in on a single signal, trace 41.
- Example use of the psplot script. Data are rescaled by the L2
norm (option 3) of each
trace before plotting by bplt
- Using bplt to focus on trace 41 from 50 to 60 msec in time.
- Using Seismic Unix (SU) to plot BSEGY data, script psPlot-su
used.
- Plot of surface wave data using qplt. The qgraph.gp output
file was edited to make a Postscript figure, and that is shown here.
- First trace of figure 6 surface wave data using
tplt.
- Plots produced by traplt.m. (A). Time domain (B). Frequency
Domain
- Plots produced by profplot.m.
- Source generates both horizontal and vertical motion
- Plan view of a typical survey. Coordinate system for geophone components and impact forces.
- PCA result (file h141plt.ps) for near surface geophone station.
- Deepest level (A) is 180 degrees off from desired as shown in (B)
- Plot of channel 2 and channel 3 geophone azimuth headers. The apparent discontinuity at about 12.5 m depth is exaggerated by channel 3 passing through North, 0 deg. = 360 deg.
- Plots produced by hodoplot.m confirms that data were rotated as desired
- Difference of Source Polarizations, T-Component (bequ applied
to twav.seg)
- Sum of Source Polarizations, V-Component (bequ applied to pwav.seg)
- Alignment T-component data by first break picks for QC
- T-component Data Travel Time Inversions (a) Vertical Time (b) Observed Time
- Velocity analysis QC plot from file bvasqc.ps
- Summary plot showing velocity and semblance.
- Amplitude decay analysis QC plot from file bampqc.ps
- Summary plot showing decay as a function of frequency
- Merged figure showing both velocity and decay
- Sample of cafwd3 calculations. (A) run without data (B) run with data for comparison
- Sample of cafwd3 calculations. Quality factor varies with frequency.
- Base map for refraction survey along road shoulder.
- Plots generated with refplot.m.
- Choosing an estimate of the cross-over distance at 30 meters.
- Direct wave raypaths used by program direct.m
- Solution for overburden velocity is 923 m/s based on k004.seg, k008.seg, and k009.seg.
- Simplified delay time setup. Shots A and B shoot into geophones 1 and 2.
- Delay time solution for line along road shoulder. The structure plot has been squished vertically to remove most of the vertical exaggeration in a simple figure.
- Base map for refraction survey (line 3 goes up hill from the roadway)
- Scaled k011.seg refraction data
- Trace 20 as seen in segpic.m run
- Line 3 solution, merged xfig plots. A). Arrival times and fit, B). Structural Solution (accepted), C). Overburden velocity solution (rejected)
- Reciprocal shooting for refraction surveys across rivers. Bridge foundation investigations benefit from placing the geophones on land, and the source suspended from the bridge in the river.
- Array forming and filtering to enhance higher frequencies were needed to pick refractions. (A) shows an array formed record with strong Rayleigh and SV wave content. (B) is a blowup of the shallow data enhanced for P-waves by filtering.
- Solution from delaytmR.m analysis of 6 common geophone records and 3 constraints. Note, even after squishing the plot, there is about 12:1 vertical exaggeration on the structure.
- Color plot of semblance for example soil profile of Figure
42. The fundamental mode appears as red. A weaker higher mode is
also visible as a lighter shade of blue.
- Example Rayleigh wave model with 0.1 meter step interpolation between
control. The interpolation is linear in elastic modulus or density. See
section
7.3.2 for additional details.
- Phase velocity computed by program disper for the model of
Figure 42.
- Source wavelet for synthetic Rayleigh wave seismogram, model of
Figure
42.
- Synthetic vertical component Rayleigh wave seismogram, model of
Figure
42. See section 7.3.6 for further details.
- Manual modeling with FwdR1.m, final trial (A) dispersion and
(B) soil profile. Vs30 is in the title bar of (B) assuming parameters remain
constant down to 30 meters.
- Automated modeling with invR1.m. Initial model and
intermediate models are shown in cyan. The 3rd, terminating iteration, is
shown
in red. The fit can be compared to that achieved in Figure 46.
The
model is shown for the 3rd iteration and is tabulated in the caption of (B).
Note that both velocity and depth of control points were free to vary.
- Automated modeling with invR1.m. (A) Dispersion as a function
of wavelength. (B) Singular values sorted by size. Only the 3 largest singular
values were used (P=3).
- SASW recording places two geophones about a center line. The FFT is
used to perform a cross correlation between the two signals in the frequency
domain. The phase velocity dispersion curve is computed from the phase of the
cross correlation and knowledge of the geophone spacing. Unwrapping of phase
is
required to compute dispersion beyond the spatial Nyquist frequency.
- (C). Geologan down-hole data. Octave program yulewalker.m is
used to select trace 30. (A) Picking a length of the autocorrelation
(nlag=116), (B) Downhole data, (C) Selected signal trace 30, (D) Yule Walker
all pole spectral estimate.
- (A) Picked portion of autocorrelation. Sets spectrum order at 156.
(B) Input file from bstk of bxcr. (C) Plot of the selected trace 30. (D) All
pole amplitude spectrum.
- Solution to Lamb's Problem (after Mooney, 1974 (15)). Step function source.
- Synthetic seismograms generated by lamb (see text for model)
- Near and Far Field computations (source in x1, motion in x1 directions).
The data have been trace qualized by the L2 norm of each offset signal to prevent
fading of the motion due to amplitude decay.
- Simple layer over a half space model used in the gendis man
page.
- Phase velocity curves computed for model in Figure 55.
- Motion-stress vectors for simple layer over a half space model of
Figure 55. A) Displacement vectors, B) Stress vectors. Horizontal motion is R1, vertical motion is R2. Horizontal stress is R3, vertical stress is R4.
- Plot of vertical component motion, trace equalized to remove amplitude
decay with offset. This permits viewing the waveform changes with offset.
Compare this to the horizontal motion in Figure 60.
- Group velocities are available by plotting matu.m from within
Octave.
- Plot of horizontal component motion, trace equalized to remove
amplitude decay with offset. This permits viewing the waveform changes with
offset. Compare this to the vertical motion in Figure 58.
- Wavelet plot from Octave program m0.m. Note that the
bandwidth is less than conventional definitions would imply. When you set
(fmin,fmax) in waves.d, you are basically setting nearly the
complete limit of frequencies. The program reduces the bandwidth to approximately and
. This figure has been enlarged to show detail with the axis command.
- Plot of file bdifwavV.seg, differentiated wavV.seg
simulates what a velocity geophone might see. Compare to Figure
58.
- Plot of file bdifwavV.seg, differentiated wavV.seg
simulates what a velocity geophone might see. Only near offset signals are shown
for easier comparison.
- (A). Correct waves computation of dispersion. (B).
Illustrates too large a depth difference between top and bottom of the discontinuity.
The solution is to make the discontinuity more abrupt in disper.d or
decreasing stepz in waves.d to remove the glitches.
- (A). Kelvin-Voigt (KV) representation for both vibrator and wave assemblage. (B) Kelvin-Voigt-Maxwell-Biot (KVMB) representation.
- Octave program, kvKVMBscan.m, can be run to illustrate the effects which largely depend on porosity. Shown are cases for different mass ratios of solid frame and pore fluid.
- Octave program, kdKVMBscan.m, can be run to illustrate the effects which largely depend on porosity and frequency of shaking. Shown are the case for 15 Hz shaking. The user can choose a horizontal axis of either (A) hydraulic conductivity (m/s), or (B) ``pore diameter (mm)''
- Octave program, fqKVMBscan.m, can be run to illustrate the relationships possible between hydraulic conductivity and KV damping ratio, the metric for viscous friction.
- Octave program, KD4kvmb.m prompts the user for porosity (n), stiffness (), damping (), frequency of shaking and related uncertainties. Then when run, a display of the solution is given in a message box. Also show is the graphical image of the process. The and values produce a KV damping ratio that is represented by the horizontal line that intersects the KVMB to KV curve. The two intersections are the solution.
pm
2018-04-08