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Core Angular Momentum and the IERS Sub-Centers Activity for Monitoring Global Geophysical FluidsThe part of the grant was to use recordings of seismic waves travelling through the earth's core (PKP waves) to study the inner core rotation and constraints on possible density anomalies in the fluid core. The shapes and relative arrival times of such waves associated with a common source were used to reduce the uncertainties in source location and excitation and the effect of unknown mantle structure. The major effort of the project is to assemble historical seismograms with long observing base lines. We have found original paper records of SSI earthquakes at COL between 1951 and 1966 in a warehouse of the U.S. Geological Survey office in Golden, Colorado, extending the previous measurements at COL by Song and Richards [1996] further back 15 years. Also in Alaska, the University of Alaska, Fairbanks Geophysical Institute (UAFGI) has been operating the Alaskan Seismic Network with over 100 stations since the late 1960s. Virtually complete archives of seismograms are still available at UAFGI. Unfortunately, most of the archives are in microchip form (develocorders), for which the use of waveforms is impossible. Paper seismograms (helicorders) are available for a limited number of stations, and digital recordings of analog signals started around 1989. Of the paper records obtained, stations at Gilmore Dome (GLM, very close to COL), Yukon (FYU), McKinley (MCK), and Sheep Creek Mountain (SCM) have the most complete continuous recordings.
Document ID
20000092431
Acquisition Source
Goddard Space Flight Center
Document Type
Contractor or Grantee Report
Authors
Song, Xia-Dong
(Lamont-Doherty Geological Observatory Palisades, NY United States)
Chao, Benjamin
Date Acquired
August 19, 2013
Publication Date
January 1, 1999
Subject Category
Geophysics
Funding Number(s)
CONTRACT_GRANT: NAG5-7673
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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