Record sections from partially reversed refraction lines in
northern British Columbia show that the amplitudes of upper mantle
arrivals vary smoothly with distance. The pattern of crustal arrival
amplitudes is not smooth. Normalization of the seismograms to remove the
amplification caused by shot size and instrument response show the
effects of recording sites on Pn amplitudes are minimal.
Models derived from ray theory indicate a crust which thins from about 40 km in the Omineca Crystalline Belt to about 25 km in the Insular Trough. The average Pn velocity is 8.06 km/s. The average crustal velocity is 6.4 km/s. The secondary energy would indicate the models are greatly simplified.
A time-term profile between the Omineca Crystalline Belt and the Coast Mountains suggests a Mohorovicic transition which is characterized by two significant topographic wavelengths. The shorter (200 km) wavelength correlates roughly with the Cordilleran structural elements of Wheeler et al. (1972). The larger (800 km) wavelength may have tectonic significance. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/32556 |
| Date | January 1973 |
| Creators | Forsyth, David A.G. |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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