Sunday, May 31, 2009

North Korea nuclear test seismogram - crustal phases


Back on January 17, I had an entry on crustal phases. We should do a short review to understand the nomenclature shown in the diagram in the last blog for the seismic phases seen on China seismograms after the Korea nuclear test.

You can find a listing of seismic phases here.

Note in particular the phases shown in the previous quake observed for the NK nuclear test:
  • Pg - at short distances, an upgoing P wave from a source in the upper crust; otherwise, a wave refracted from a mid-crustal discontinuity
  • Pn - a P wave refracted along the crust-mantle boundary
  • Sg - at short distances, an upgoing S wave from a source in the upper crust
  • Sn - an S wave refracted along the crust-mantle boundary
Rayleigh and L waves are surface waves.

1 comment:

  1. The monitoring results are far from conclusive. There could be other causes of a shallow 4.7 magnitude seismic event in the Korean Peninsula.


    See:


    http://notionscapital.wordpress.com/2009/05/31/north-korea-alternative-theory/

    ReplyDelete

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