Seismology
Laboratory and Computing Facilities
The Reflection Seismology Laboratory consists of a workstation based interactive
processing system. We have several dedicated SGI workstations and a Sun Ultra
with a total of 164 GByte external disk space. These workstations provide a
variety of platforms for seismic data analysis. In addition the Reflection Seismology
Laboratory contains several Macintosh computers and PCs for word processing,
graphics applications, and some components of seismic data reduction.
We run OMEGA seismic processing software produced by Western Geophysical on
Silicon Graphics workstations. This software has capabilities for both interactive
and batch processing of 2-D and 3-D seismic data through initial brute stack
and final migrated sections. A particularly nice feature of this system is the
ability to display gathers on the screen and test various processing parameters
interactively for gain control, filter design, trace correlation, spectral analysis,
deconvolution, mute, f-k filter design, and velocity analysis. The interactive
feature allows the user to move through large volumes of data with relative
ease choosing parameters carefully as data quality and character change with
changing geology. Interactive processing parameters are saved in a file for
later use in batch processing. The software package contains a variety of advanced
data processing options for multiple attenuation, noise reduction, waveform
processing, synthetic seismogram generation, attibute analysis, amplitude vs.
offset (AVO) analysis, tau-p transform, and both pre-stack and post-stack imaging.
We run SEISVISION for 3-D data interpretation. This software includes a full
suite of applications for importing data, fault and stratigraphic horizon interpretation
and mapping, surface and isopach, contouring, conversion from time to depth,
data visualization, and display. In addition to the reflection data processing
and interpretation we have the standard USGS wide angle reflection/refraction
analysis package based on Cerveny asymptotic ray tracing, and several travel
time inversion schemes. This software allows us to forward model traveltimes
and amplitudes of wide-aperture seismic data sets as well as invert traveltime
data for velocity structure. In addition we have a variety of software for analysis
and display of earthquake data including: DATASCOPE, HYPOCENTER, xmap, GMT,
and FPFIT/FPPLOT.
A variety of input and output devices are available: 3480 tape cartridge, 8mm
exabyte tape drive, 4mm DAT drive, CD ROM, player, laserwriter, scanner, film
recorder, 24-inch electrostatic plotter, and 36-inch HP color plotter.
Seismology Field Equipment
For seismic data acquisition we have a Bison 9048 DIFP seismograph. This is
a multichannel (48 channels), lightweight, portable seismograph, with over 130
dB of dynamic range to acquire high quality, high resolution seismic reflection
and refraction data. We also have geophones, cables, and a field computer to
complete the seismic field acquisition system. We also have a GSSI SIR-System
2 Ground Penetrating Radar unit to image shallow earth structure. GPR data can
augment and complement subsurface information from seismic profiling in a wide
variety of both geologic and environmental applications and is particularly
useful in shallow fresh water lakes. We also operate and maintain a permanent
seismic station on the Lehigh Campus.