An application of ray theory to the investigation of seismic head wave post-Pn phases
Abstract
At epicentral distances between 200 and 1,000 kilometers the first energy to arrive from a seismic event is generally identified as a compressional headwave, Pn. According to Snell's Law, there are eleven separate waveforms to be expected, following Pn. These are termed the post-Pn phases and are the result of various conversions upon reflection from the surface, refraction along the uppermost mantle as a compressional wave, and returning to the surface as a compressional or shear phase. These post-Pn phases are expected to arrive at the seismic station in one to twenty seconds after the Pn event and prior to the P* event, which has traveled along the Conrad discontinuity. For the shorter epicentral distances, in the 200 kilometer range, some of the post-Pn phases are seen to arrive after P*. Only the earthquakes which will have originated from a shallow, crustal focus, usually of three to twenty kilometer depth are considered.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1981
- Bibcode:
- 1981PhDT........48C
- Keywords:
-
- Compression Waves;
- Earthquakes;
- P Waves;
- Refraction;
- Seismic Waves;
- Foci;
- Microseisms;
- Seismographs;
- Seismology;
- Shock Waves;
- Waveforms;
- Geophysics