Skip to main content

seismic-wave modes

seismic-wave modes The conventional notation ascribed to seismic waves on the basis of their travel times from their earthquake sources. Letters are used to designate the type of wave along the different portions of its travel path: P and S refer to P-waves and S-waves that do not travel through the Earth's core; K and I refer to P-waves only, which travel through the core and inner core respectively. The letter J refers to S-waves which are generated by the conversion of incident P-waves at the boundary between the inner and outer cores, and which travel only in that mode within the solid inner core. As they propagate towards the Earth's surface, J-waves are reconverted back into P-waves at the inner core boundary. A repetition of the letters (e.g. PP, SS) indicates that the waves have been reflected at the Earth's surface; reflection at the outer edge of the core is indicated by ‘c’ (e.g. PcP, PcS). For example, the wave PKIKP travels from the surface, through the mantle to the outer core, into the inner core, and then back to the surface; the wave PPP has travelled only in the crust and upper mantle, and has been reflected twice off the surface.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"seismic-wave modes." A Dictionary of Earth Sciences. . Encyclopedia.com. 16 Nov. 2018 <https://www.encyclopedia.com>.

"seismic-wave modes." A Dictionary of Earth Sciences. . Encyclopedia.com. (November 16, 2018). https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/seismic-wave-modes

"seismic-wave modes." A Dictionary of Earth Sciences. . Retrieved November 16, 2018 from Encyclopedia.com: https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/seismic-wave-modes

Learn more about citation styles

Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

http://www.mla.org/style

The Chicago Manual of Style

http://www.chicagomanualofstyle.org/tools_citationguide.html

American Psychological Association

http://apastyle.apa.org/

Notes:
  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.