Strain, Rotation, and Displacement Gradient Time Series

associated with


Observation and Prediction of Dynamic Ground Strains, Tilts, and Torsions Caused by the M6.0 2004 Parkfield, California, Earthquake and Aftershocks Derived from UPSAR Array Observations

by Paul Spudich and Jon B. Fletcher

accepted, Bulletin of the Seismological Society of America, to appear August, 2008.

We present in this supplement the strain, rotation, and displacement gradient time series calculated in that paper for the main shock. We present these time series for subarray 5-12 in the 0.1 - 1.4 Hz band, and for subarrays 1-3 and 8-11 in the 0.1 - 3.6 Hz bands. UPSAR array main shock accelerations, velocities, and displacements may be downloaded from National Strong Motion Program website.

Downloadable File

spudich-fletcher-timeseries.zip. (0.9 Mb). Compressed file containing three time series files. This file may be uncompressed on a Windows machine using PKUNZIP, WinZip, or other software. On a Mac this file can be uncompressed using StuffIt Expander or other software. On linux/unix the file may be uncompressed using the unzip command.

NOTE: These time series are band-limited. Their peak values do not agree with the broadband peak amplitudes listed in Table 5. Their peak amplitudes are slightly lower than the values in Table 3, owing to decimation to 50 samples / s. Peak amplitudes in that table are calculated using max(*) for dilatations and max(abs(*)) for all other quantities.

Contents of the zip file:

pkf_main_sub1_3_3.6hz.txt - Main shock time series, subarray 1-3, 0.1 - 3.6 Hz pass band.

pkf_main_sub8_11_3.6hz.txt - Main shock time series, subarray 8-11, 0.1 - 3.6 Hz pass band.

pkf_main_sub5_12_1.4hz.txt - Main shock time series, subarray 5-12, 0.1 - 1.4 Hz pass band.

Time Series File Format

Files are ASCII.

Record 1: A title, identifying the earthquake, the subarray, and the pass-band.

Record 2: File version number, with time stamp of production date, in Pacific Daylight Time.

Record 3: Titles for each column.

Records 4 - end: Time series of 13 quantities, 1 quantity per column.

Column 1: Time (s) corresponding to each sample. Time is measured from the start of each time series. Time zero has no physical significance.

Column 2: Total dilatation (unitless). Corresponds to d in Appendix A.

Column 3: Horizontal dilatation (unitless). Corresponds to dh in Appendix A.

Column 4: Maximum total shear strain (unitless). Corresponds to s in Appendix A.

Column 5: Maximum horizontal shear strain (unitless). Corresponds to sh in Appendix A.

Column 6: Torsion (radians). Corresponds to w3 in Appendix A.

Column 7: Tilt (radians). Corresponds to sqrt(w12+w22) in Appendix A.

Column 8: Displacement gradient (unitless). Corresponds to p1 in Appendix A.

Column 9: Displacement gradient (unitless). Corresponds to p2 in Appendix A.

Column 10: Displacement gradient (unitless). Corresponds to p3 in Appendix A.

Column 11: Displacement gradient (unitless). Corresponds to p4 in Appendix A.

Column 12: Displacement gradient (unitless). Corresponds to p5 in Appendix A.

Column 13: Displacement gradient (unitless). Corresponds to p6 in Appendix A.


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