Data Report
Event / Nenana, AK
Contributed by USGS
The Trans Alaska Pipeline data provided by Alyeska have been revised for
the 20021023 11:27 UTC Mw 6.7 Nenana, Alaska earthquake (lat 63.626, lon
-148.016).
Important note to users of these data (posted 05/22/2003:
The information in the headers of these files is revised from that in the
headers of the files originally served by the USGS. Changes include:
1) Revised information about the nominal filter characteristics, as
determined from an analysis of a circuit diagram for the filter. Note
in particular that the highpass corner is at 0.1 Hz, not 0.01 Hz as was
indicated in the files originally provided by Alyeska, and that the
highpass and lowpass filters each have 2 poles rather than 1. Details
of the nominal filter characteristics are provided in the headers.
Due to uncertainties in the instrument response, only uncorrected
acceleration time series data are currently being served. Results
from bench tests using components similar to those deployed in the
field show deviations from nominal characteristics that could produce
variations of up to 20% in displacements determined by double
integration of the acceleration time series. The USGS is working with
Alyeska to determine more accurate calibrations, and any new
information will be released as soon as it is available.
2) The make and model of the digitizer, along with estimates of the
digitizing accuracy and precision are included.
3) Additional information about the baseline correction applied to the
data.
The folders (directories) and filenames for this earthquake have been
changed from "20021023_1" to "20021023_1127".
Regards,
Kent Fogleman
____________________________________________________
Kent A. Fogleman
U.S. Geological Survey
National Strong-Motion Data Center
345 Middlefield Rd., MS 977
Menlo Park, CA 94025
office: 650-329-4745
e-mail: fogleman@usgs.gov
web: http://nsmp.wr.usgs.gov