User:Jreinstr/sandbox

Article to improve: Receiver function.

Some things to discuss:

- Method (explain equation and how it works)

- Applications

- Ramifications

Possible citations: (potentially use figures from these papers)

Receiver function

A receiver function technique is a way to model the boundary layers and structure of the Earth by using the information from teleseismic earthquakes recorded at a three component seismograph.

A teleseismic P-wave will generate P to S conversions at boundaries, such as the Moho (crust-mantle boundary), beneath the seismograph. The difference in travel time between the generated S-wave and P-wave contains information about the distance to the boundary and if further reverberations are included more detailed structure can be resolved. This is done by deconvolution of the incoming vertical and longitudinal components of the seismogram which removes the common part of the components - namely, the source and travel path information. The resulting waveform is the receiver function.

Similarly, a teleseismic S-wave will generate an S to P conversion beneath the seismic station.

Method

blah blah blah

• Moho (crust // mantle boundary) is primary / most useful boundary bc big composition differences = big seismic wave behavior differences
• high level: comes from P waves: combining graph of horizontal motion of wave with vertical motion of wave to detect S phases
• At Moho, P waves convert to S waves
  • key observation is that these waves produce additional waves that reflect between crust and moho
  • can use these additional waves together in one model to create more accurate picture of moho
• Five phases of waves that come off of P wave thingy: PpPmp PpSmp, Ps, PpPms, PpSms
  • First three hard to measure; last two can measure using horizontal motion of the P waves (NOT S which is the direct one)
  • Use vertical component to as guide for what would look like without the S waves
  • Works best on earthquakes below 600km to minimize surface stuff at 30 to 80 degrees angle below seismograph station
• All these waveforms are converted to a synthetic seismogram

Applications

blah blah blah

• Obtain 3D view of seismic velocities in crust + mantle "crustal models"
  • Useful into to support other seismological studies
• Can be used to get info from naturally occurring earthquakes as opposed to active experiments where seismic waves are triggered
  • Also provides higher resolution results than active experiments
  • Provides a 3D picture rather than cross-sections like CSS (controlled source seismology)
• Example: find depressions in the moho below mountains
• Understanding more about earthquakes (which can cause disasters)

References

• C. A. Langston: Structure under Mount Rainier, Washington, inferred from teleseismic body waves, J. Geophys. Res. 84(B9), 4749–4762, 1979.
• Charles J. Ammon, George E. Randall, and George Zandt: On the Nonuniqueness of Receiver Function Inversions, Journal of Geophysical Research 95(B10), 15303–15318, 1990.
• Frederiksen, A. W., and M. G. Bostock: Modelling teleseismic waves in dipping anisotropic structures, Geophysical Journal International 141, 401–412, 2000.
• Vinnik, L. P. (1977), Detection of waves converted from P to SV in the mantle, Phys. Earth Planet. Inter., 15(1), 39-45.

External links

• An Overview of Receiver-Function Analysis