Loading...
Please wait, while we are loading the content...
Similar Documents
Relationships of earthquakes (and earthquake-associated mass movements) and polar motion as determined by kalman filtered, very-long-baseline-interferometry
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Preisig, Joseph Richard Mark |
| Copyright Year | 1988 |
| Description | A Kalman filter was designed to yield optimal estimates of geophysical parameters from Very Long Baseline Interferometry (VLBI) group delay data. The geophysical parameters are the polar motion components, adjustments to nutation in obliquity and longitude, and a change in the length of day parameter. The VLBI clock (and clock rate) parameters and atmospheric zenith delay parameters are estimated simultaneously. Filter background is explained. The IRIS (International Radio Interferometric Surveying) VLBI data are Kalman filtered. The resulting polar motion estimates are examined. There are polar motion signatures at the times of three large earthquakes occurring in 1984 to 1986: Mexico, 19 September, 1985 (Magnitude M sub s = 8.1); Chile, 3 March, 1985 (M sub s = 7.8); and Taiwan, 14 November, 1986 (M sub s = 7.8). Breaks in polar motion occurring about 20 days after the earthquakes appear to correlate well with the onset of increased regional seismic activity and a return to more normal seismicity (respectively). While the contribution of these three earthquakes to polar motion excitations is small, the cumulative excitation due to earthquakes, or seismic phenomena over a Chandler wobble damping period may be significant. Mechanisms for polar motion excitation due to solid earth phenomena are examined. Excitation functions are computed, but the data spans are too short to draw conclusions based on these data. |
| File Size | 7401155 |
| Page Count | 254 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19890012059 |
| Archival Resource Key | ark:/13960/t9g49kx6f |
| Language | English |
| Publisher Date | 1988-10-01 |
| Access Restriction | Open |
| Subject Keyword | Geophysics Earth Rotation Very Long Base Interferometry Earthquakes Seismology Lithosphere Geodesy Data Smoothing Parameterization Kalman Filters Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
